aboutsummaryrefslogtreecommitdiff
path: root/bfd/mmo.c
blob: a9f812b3308f5f0ecd4007a7f25d57913e5d4811 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
/* BFD back-end for mmo objects (MMIX-specific object-format).
   Copyright (C) 2001-2023 Free Software Foundation, Inc.
   Written by Hans-Peter Nilsson (hp@bitrange.com).
   Infrastructure and other bits originally copied from srec.c and
   binary.c.

   This file is part of BFD, the Binary File Descriptor library.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */


/*
SECTION
	mmo backend

	The mmo object format is used exclusively together with Professor
	Donald E.@: Knuth's educational 64-bit processor MMIX.  The simulator
	@command{mmix} which is available at
	@url{http://mmix.cs.hm.edu/src/index.html}
	understands this format.  That package also includes a combined
	assembler and linker called @command{mmixal}.  The mmo format has
	no advantages feature-wise compared to e.g. ELF.  It is a simple
	non-relocatable object format with no support for archives or
	debugging information, except for symbol value information and
	line numbers (which is not yet implemented in BFD).  See
	@url{http://mmix.cs.hm.edu/} for more
	information about MMIX.  The ELF format is used for intermediate
	object files in the BFD implementation.

@c We want to xref the symbol table node.  A feature in "chew"
@c requires that "commands" do not contain spaces in the
@c arguments.  Hence the hyphen in "Symbol-table".
@menu
@* File layout::
@* Symbol-table::
@* mmo section mapping::
@end menu

INODE
File layout, Symbol-table, mmo, mmo
SUBSECTION
	File layout

	The mmo file contents is not partitioned into named sections as
	with e.g.@: ELF.  Memory areas is formed by specifying the
	location of the data that follows.  Only the memory area
	@samp{0x0000@dots{}00} to @samp{0x01ff@dots{}ff} is executable, so
	it is used for code (and constants) and the area
	@samp{0x2000@dots{}00} to @samp{0x20ff@dots{}ff} is used for
	writable data.  @xref{mmo section mapping}.

	There is provision for specifying ``special data'' of 65536
	different types.  We use type 80 (decimal), arbitrarily chosen the
	same as the ELF <<e_machine>> number for MMIX, filling it with
	section information normally found in ELF objects. @xref{mmo
	section mapping}.

	Contents is entered as 32-bit words, xor:ed over previous
	contents, always zero-initialized.  A word that starts with the
	byte @samp{0x98} forms a command called a @samp{lopcode}, where
	the next byte distinguished between the thirteen lopcodes.  The
	two remaining bytes, called the @samp{Y} and @samp{Z} fields, or
	the @samp{YZ} field (a 16-bit big-endian number), are used for
	various purposes different for each lopcode.  As documented in
	@url{http://mmix.cs.hm.edu/doc/mmixal.pdf},
	the lopcodes are:

	@table @code
	@item lop_quote
	0x98000001.  The next word is contents, regardless of whether it
	starts with 0x98 or not.

	@item lop_loc
	0x9801YYZZ, where @samp{Z} is 1 or 2.  This is a location
	directive, setting the location for the next data to the next
	32-bit word (for @math{Z = 1}) or 64-bit word (for @math{Z = 2}),
	plus @math{Y * 2^56}.  Normally @samp{Y} is 0 for the text segment
	and 2 for the data segment.  Beware that the low bits of non-
	tetrabyte-aligned values are silently discarded when being
	automatically incremented and when storing contents (in contrast
	to e.g. its use as current location when followed by lop_fixo
	et al before the next possibly-quoted tetrabyte contents).

	@item lop_skip
	0x9802YYZZ.  Increase the current location by @samp{YZ} bytes.

	@item lop_fixo
	0x9803YYZZ, where @samp{Z} is 1 or 2.  Store the current location
	as 64 bits into the location pointed to by the next 32-bit
	(@math{Z = 1}) or 64-bit (@math{Z = 2}) word, plus @math{Y *
	2^56}.

	@item lop_fixr
	0x9804YYZZ.  @samp{YZ} is stored into the current location plus
	@math{2 - 4 * YZ}.

	@item lop_fixrx
	0x980500ZZ.  @samp{Z} is 16 or 24.  A value @samp{L} derived from
	the following 32-bit word are used in a manner similar to
	@samp{YZ} in lop_fixr: it is xor:ed into the current location
	minus @math{4 * L}.  The first byte of the word is 0 or 1.  If it
	is 1, then @math{L = (@var{lowest 24 bits of word}) - 2^Z}, if 0,
	then @math{L = (@var{lowest 24 bits of word})}.

	@item lop_file
	0x9806YYZZ.  @samp{Y} is the file number, @samp{Z} is count of
	32-bit words.  Set the file number to @samp{Y} and the line
	counter to 0.  The next @math{Z * 4} bytes contain the file name,
	padded with zeros if the count is not a multiple of four.  The
	same @samp{Y} may occur multiple times, but @samp{Z} must be 0 for
	all but the first occurrence.

	@item lop_line
	0x9807YYZZ.  @samp{YZ} is the line number.  Together with
	lop_file, it forms the source location for the next 32-bit word.
	Note that for each non-lopcode 32-bit word, line numbers are
	assumed incremented by one.

	@item lop_spec
	0x9808YYZZ.  @samp{YZ} is the type number.  Data until the next
	lopcode other than lop_quote forms special data of type @samp{YZ}.
	@xref{mmo section mapping}.

	Other types than 80, (or type 80 with a content that does not
	parse) is stored in sections named <<.MMIX.spec_data.@var{n}>>
	where @var{n} is the @samp{YZ}-type.  The flags for such a
	sections say not to allocate or load the data.  The vma is 0.
	Contents of multiple occurrences of special data @var{n} is
	concatenated to the data of the previous lop_spec @var{n}s.  The
	location in data or code at which the lop_spec occurred is lost.

	@item lop_pre
	0x980901ZZ.  The first lopcode in a file.  The @samp{Z} field forms the
	length of header information in 32-bit words, where the first word
	tells the time in seconds since @samp{00:00:00 GMT Jan 1 1970}.

	@item lop_post
	0x980a00ZZ.  @math{Z > 32}.  This lopcode follows after all
	content-generating lopcodes in a program.  The @samp{Z} field
	denotes the value of @samp{rG} at the beginning of the program.
	The following @math{256 - Z} big-endian 64-bit words are loaded
	into global registers @samp{$G} @dots{} @samp{$255}.

	@item lop_stab
	0x980b0000.  The next-to-last lopcode in a program.  Must follow
	immediately after the lop_post lopcode and its data.  After this
	lopcode follows all symbols in a compressed format
	(@pxref{Symbol-table}).

	@item lop_end
	0x980cYYZZ.  The last lopcode in a program.  It must follow the
	lop_stab lopcode and its data.  The @samp{YZ} field contains the
	number of 32-bit words of symbol table information after the
	preceding lop_stab lopcode.
	@end table

	Note that the lopcode "fixups"; <<lop_fixr>>, <<lop_fixrx>> and
	<<lop_fixo>> are not generated by BFD, but are handled.  They are
	generated by <<mmixal>>.

EXAMPLE
	This trivial one-label, one-instruction file:

| :Main TRAP 1,2,3

	can be represented this way in mmo:

| 0x98090101 - lop_pre, one 32-bit word with timestamp.
| <timestamp>
| 0x98010002 - lop_loc, text segment, using a 64-bit address.
|              Note that mmixal does not emit this for the file above.
| 0x00000000 - Address, high 32 bits.
| 0x00000000 - Address, low 32 bits.
| 0x98060002 - lop_file, 2 32-bit words for file-name.
| 0x74657374 - "test"
| 0x2e730000 - ".s\0\0"
| 0x98070001 - lop_line, line 1.
| 0x00010203 - TRAP 1,2,3
| 0x980a00ff - lop_post, setting $255 to 0.
| 0x00000000
| 0x00000000
| 0x980b0000 - lop_stab for ":Main" = 0, serial 1.
| 0x203a4040   @xref{Symbol-table}.
| 0x10404020
| 0x4d206120
| 0x69016e00
| 0x81000000
| 0x980c0005 - lop_end; symbol table contained five 32-bit words.  */

#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
#include "libiberty.h"
#include "elf/mmix.h"
#include "opcode/mmix.h"

#define LOP 0x98u
#define LOP_QUOTE 0
#define LOP_LOC 1
#define LOP_SKIP 2
#define LOP_FIXO 3
#define LOP_FIXR 4
#define LOP_FIXRX 5
#define LOP_FILE 6
#define LOP_LINE 7
#define LOP_SPEC 8
#define LOP_PRE 9
#define LOP_POST 10
#define LOP_STAB 11
#define LOP_END 12

#define LOP_QUOTE_NEXT ((LOP << 24) | (LOP_QUOTE << 16) | 1)
#define SPEC_DATA_SECTION 80
#define LOP_SPEC_SECTION \
 ((LOP << 24) | (LOP_SPEC << 16) | SPEC_DATA_SECTION)

/* Must be a power of two.  If you change this to be >= 64k, you need a
   new test-case; the ld test b-loc64k.d touches chunk-size problem areas.  */
#define MMO_SEC_CONTENTS_CHUNK_SIZE (1 << 15)

/* An arbitrary number for the maximum length section name size.  */
#define MAX_SECTION_NAME_SIZE (1024 * 1024)

/* A quite arbitrary number for the maximum length section size.  */
#define MAX_ARTIFICIAL_SECTION_SIZE (1024 * 1024 * 1024)

#define MMO3_WCHAR 0x80
#define MMO3_LEFT 0x40
#define MMO3_MIDDLE 0x20
#define MMO3_RIGHT 0x10
#define MMO3_TYPEBITS 0xf
#define MMO3_REGQUAL_BITS 0xf
#define MMO3_UNDEF 2
#define MMO3_DATA 8
#define MMO3_SYMBITS 0x2f

/* Put these everywhere in new code.  */
#define FATAL_DEBUG						\
 _bfd_abort (__FILE__, __LINE__,				\
	     "Internal: Non-debugged code (test-case missing)")

#define BAD_CASE(x)				\
 _bfd_abort (__FILE__, __LINE__,		\
	     "bad case for " #x)

enum mmo_sym_type { mmo_reg_sym, mmo_undef_sym, mmo_data_sym, mmo_abs_sym};

/* When scanning the mmo file, a linked list of mmo_symbol
   structures is built to represent the symbol table (if there is
   one).  */

struct mmo_symbol
  {
    struct mmo_symbol *next;
    char *name;
    bfd_vma value;
    enum mmo_sym_type sym_type;
    unsigned int serno;
  };

struct mmo_data_list_struct
  {
    struct mmo_data_list_struct *next;
    bfd_vma where;
    bfd_size_type size;
    bfd_size_type allocated_size;
    bfd_byte data[1];
  };

typedef struct mmo_data_list_struct mmo_data_list_type;

struct mmo_symbol_trie
  {
    struct mmo_symbol_trie *left;
    struct mmo_symbol_trie *right;
    struct mmo_symbol_trie *middle;

    bfd_byte symchar;

    /* A zero name means there's nothing here.  */
    struct mmo_symbol sym;
  };

/* The mmo tdata information.  */

struct mmo_data_struct
  {
    struct mmo_symbol *symbols;
    struct mmo_symbol *symtail;
    asymbol *csymbols;

    /* File representation of time (NULL) when this file was created.  */
    bfd_byte created[4];

    /* When we're reading bytes recursively, check this occasionally.
       Also holds write errors.  */
    bool have_error;

    /* Max symbol length that may appear in the lop_stab table.  Note that
       this table might just hold a subset of symbols for not-really large
       programs, as it can only be 65536 * 4 bytes large.  */
    int max_symbol_length;

    /* Here's the symbol we build in lop_stab.  */
    char *lop_stab_symbol;

    /* Index into lop_stab_symbol for the next character when parsing the
       symbol information.  */
    int symbol_position;

    /* When creating arbitrary sections, we need to count section numbers.  */
    int sec_no;

    /* When writing or reading byte-wise, we need to count the bytes
       within a 32-bit word.  */
    int byte_no;

    /* We also need a buffer to hold the bytes we count reading or writing.  */
    bfd_byte buf[4];

    /* Whether we've calculated symbol consistency requirement yet.  We do this
       when-needed, which must be at some time after all section
       contents is known.  */
    bool symbol_consistency_override_calculated;

    /* Whether to consistency-check symbol values, in particular "Main".  */
    bool ignore_symbol_consistency;
  };

typedef struct mmo_data_struct tdata_type;

struct mmo_section_data_struct
  {
    mmo_data_list_type *head;
    mmo_data_list_type *tail;
  };

#define mmo_section_data(sec) \
  ((struct mmo_section_data_struct *) (sec)->used_by_bfd)

/* These structures are used in bfd_map_over_sections constructs.  */

/* Used when writing out sections; all but the register contents section
   which is stored in reg_section.  */
struct mmo_write_sec_info
  {
    asection *reg_section;
    bool retval;
  };

/* Used when trying to find a section corresponding to addr.  */
struct mmo_find_sec_info
  {
    asection *sec;
    bfd_vma addr;
  };

static bool mmo_bfd_copy_private_bfd_data (bfd *, bfd *);
static void mmo_write_section_unless_reg_contents (bfd *, asection *, void *);
static void mmo_find_sec_w_addr (bfd *, asection *, void *);
static void mmo_find_sec_w_addr_grow (bfd *, asection *, void *);
static asection *mmo_make_section (bfd *, const char *);
static void mmo_get_symbol_info (bfd *, asymbol *, symbol_info *);
static void mmo_print_symbol (bfd *, void *, asymbol *,
			      bfd_print_symbol_type);
static void mmo_init (void);
static bool mmo_mkobject (bfd *);
static bool mmo_scan (bfd *);
static asection *mmo_decide_section (bfd *, bfd_vma);
static asection *mmo_get_generic_spec_data_section (bfd *, int);
static asection *mmo_get_spec_section (bfd *, int);
static bfd_byte *mmo_get_loc (asection *, bfd_vma, unsigned int);
static bfd_cleanup mmo_object_p (bfd *);
static void mmo_map_set_sizes (bfd *, asection *, void *);
static bool mmo_get_symbols (bfd *);
static bool mmo_create_symbol (bfd *, const char *, bfd_vma,
			       enum mmo_sym_type, unsigned int);
static bool mmo_get_section_contents (bfd *, asection *, void *,
				      file_ptr, bfd_size_type);
static long mmo_get_symtab_upper_bound (bfd *);
static long mmo_canonicalize_symtab (bfd *, asymbol **);
static void mmo_get_symbol_info (bfd *, asymbol *, symbol_info *);
static void mmo_print_symbol (bfd *, void *, asymbol *,
			      bfd_print_symbol_type);
static bool mmo_set_section_contents (bfd *, sec_ptr, const void *,
				      file_ptr, bfd_size_type);
static int mmo_sizeof_headers (bfd *, struct bfd_link_info *);
static bool mmo_internal_write_header (bfd *);
static bool mmo_internal_write_post (bfd *, int, asection *);
static bool mmo_internal_add_3_sym (bfd *, struct mmo_symbol_trie *,
					   const struct mmo_symbol *);
static unsigned int mmo_internal_3_length (bfd *, struct mmo_symbol_trie *);
static void mmo_internal_3_dump (bfd *, struct mmo_symbol_trie *);
static void mmo_beb128_out (bfd *, int, int);
static bool mmo_internal_write_section (bfd *, asection *);
static void mmo_write_tetra (bfd *, unsigned int);
static void mmo_write_tetra_raw (bfd *, unsigned int);
static void mmo_write_octa (bfd *, bfd_vma);
static void mmo_write_octa_raw (bfd *, bfd_vma);
static bool mmo_write_chunk (bfd *, const bfd_byte *, unsigned int);
static bool mmo_flush_chunk (bfd *);
static bool mmo_write_loc_chunk (bfd *, bfd_vma, const bfd_byte *,
				 unsigned int, bfd_vma *);
static bool mmo_write_chunk_list (bfd *, mmo_data_list_type *);
static bool mmo_write_loc_chunk_list (bfd *, mmo_data_list_type *);
static bool mmo_write_symbols_and_terminator (bfd *);
static flagword mmo_sec_flags_from_bfd_flags (flagword);
static flagword bfd_sec_flags_from_mmo_flags (flagword);
static bfd_byte mmo_get_byte (bfd *);
static void mmo_write_byte (bfd *, bfd_byte);
static bool mmo_new_section_hook (bfd *, asection *);
static int mmo_sort_mmo_symbols (const void *, const void *);
static bool mmo_write_object_contents (bfd *);
static bool mmo_write_section_description (bfd *, asection *);
static bool mmo_has_leading_or_trailing_zero_tetra_p (bfd *, asection *);

static const char
valid_mmo_symbol_character_set[] =
{
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
  'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
  ':', '_', 126, 127, 128, 129,
  130, 131, 132, 133, 134, 135, 136, 137, 138, 139,
  140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
  150, 151, 152, 153, 154, 155, 156, 157, 158, 159,
  160, 161, 162, 163, 164, 165, 166, 167, 168, 169,
  170, 171, 172, 173, 174, 175, 176, 177, 178, 179,
  180, 181, 182, 183, 184, 185, 186, 187, 188, 189,
  190, 191, 192, 193, 194, 195, 196, 197, 198, 199,
  200, 201, 202, 203, 204, 205, 206, 207, 208, 209,
  210, 211, 212, 213, 214, 215, 216, 217, 218, 219,
  220, 221, 222, 223, 224, 225, 226, 227, 228, 229,
  230, 231, 232, 233, 234, 235, 236, 237, 238, 239,
  240, 241, 242, 243, 244, 245, 246, 247, 248, 249,
  250, 251, 252, 253, 254, 255,
  0
};


/* Get section SECNAME or create one if it doesn't exist.  When creating
   one, new memory for the name is allocated.  */

static asection *
mmo_make_section (bfd *abfd, const char *secname)
{
  asection *sec = bfd_get_section_by_name (abfd, secname);

  if (sec == NULL)
    {
      size_t len = strlen (secname) + 1;
      char *newsecname = bfd_alloc (abfd, len);

      if (newsecname == NULL)
	{
	  bfd_set_error (bfd_error_no_memory);
	  return NULL;
	}
      memcpy (newsecname, secname, len);
      sec = bfd_make_section (abfd, newsecname);
    }

  return sec;
}

/* Nothing to do, but keep as a placeholder if we need it.
   Note that state that might differ between bfd:s must not be initialized
   here, nor must it be static.  Add it to tdata information instead.  */

static void
mmo_init (void)
{
  static bool inited = false;

  if (inited)
    return;
  inited = true;
}

/* Check whether an existing file is an mmo file.  */

static bfd_cleanup
mmo_object_p (bfd *abfd)
{
  struct stat statbuf;
  bfd_byte b[4];

  mmo_init ();

  if (bfd_stat (abfd, &statbuf) < 0
      || bfd_seek (abfd, 0, SEEK_SET) != 0
      || bfd_read (b, 4, abfd) != 4)
    goto bad_final;

  /* All mmo files are a multiple of four bytes long.
     Only recognize version one.  */
  if ((statbuf.st_size % 4) != 0
      || b[0] != LOP || b[1] != LOP_PRE || b[2] != 1)
    goto bad_format;

  /* Get the last 32-bit word.  */
  if (bfd_seek (abfd, statbuf.st_size - 4, SEEK_SET) != 0
      || bfd_read (b, 4, abfd) != 4)
    goto bad_final;

  /* Check if the file ends in a lop_end lopcode. */
  if (b[0] != LOP || b[1] != LOP_END || ! mmo_mkobject (abfd))
    goto bad_format;

  /* Compute an upper bound on the max symbol length.  Not really
     important as all of the symbol information can only be 256k.  */
  abfd->tdata.mmo_data->max_symbol_length = (b[2] * 256 + b[3]) * 4;
  abfd->tdata.mmo_data->lop_stab_symbol
    = bfd_alloc (abfd, abfd->tdata.mmo_data->max_symbol_length + 1);

  if (abfd->tdata.mmo_data->lop_stab_symbol == NULL)
    {
      _bfd_error_handler
	/* xgettext:c-format */
	(_("%pB: no core to allocate a symbol %d bytes long"),
	 abfd, abfd->tdata.mmo_data->max_symbol_length);
      goto bad_final;
    }

  /* Read in everything.  */
  if (! mmo_scan (abfd))
    goto bad_format;

  if (abfd->symcount > 0)
    abfd->flags |= HAS_SYMS;

  /* You'll have to tweak this if you want to use this format for other
     arches (not recommended due to its small-size limitations).  Look at
     the ELF format for how to make it target-generic.  */
  if (! bfd_default_set_arch_mach (abfd, bfd_arch_mmix, 0))
    goto bad_format;

  return _bfd_no_cleanup;

 bad_format:
  bfd_set_error (bfd_error_wrong_format);
 bad_final:
  return NULL;
}

/* Set up the mmo tdata information.  */

static bool
mmo_mkobject (bfd *abfd)
{
  mmo_init ();

  if (abfd->tdata.mmo_data == NULL)
    {
      time_t created;

      /* All fields are zero-initialized, so we don't have to explicitly
	 initialize most.  */
      tdata_type *tdata = (tdata_type *) bfd_zalloc (abfd, sizeof (tdata_type));
      if (tdata == NULL)
	return false;

      created = time (NULL);
      bfd_put_32 (abfd, created, tdata->created);

      abfd->tdata.mmo_data = tdata;
    }

  return true;
}

static bool
mmo_section_has_contents (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *p ATTRIBUTE_UNUSED)
{
  /* The point is to match what --extract-symbols does (well, negated).  */
  return bfd_section_size (sec) != 0;
}

/* Find out whether we should omit symbol consistency checks for this
   bfd and cache the value.

   This function must only be called when all section contents is
   known.  However, calculating symbol consistency at the time the
   private BFD data is initialized is too late for some uses.  */

static bool
mmo_ignore_symbol_consistency (bfd *abfd)
{
  if (!abfd->tdata.mmo_data->symbol_consistency_override_calculated)
    {
      abfd->tdata.mmo_data->ignore_symbol_consistency =
	bfd_sections_find_if (abfd, mmo_section_has_contents, NULL) == NULL;

      abfd->tdata.mmo_data->symbol_consistency_override_calculated = true;
    }

  return abfd->tdata.mmo_data->ignore_symbol_consistency;
}

static bool
mmo_bfd_copy_private_bfd_data (bfd *ibfd, bfd *obfd)
{
  if (bfd_get_flavour (ibfd) != bfd_target_mmo_flavour
      || bfd_get_flavour (obfd) != bfd_target_mmo_flavour)
    return true;

  /* Copy the time the copied-from file was created.  If people want the
     time the file was last *modified*, they have that in the normal file
     information.  */
  memcpy (obfd->tdata.mmo_data->created, ibfd->tdata.mmo_data->created,
	  sizeof (obfd->tdata.mmo_data->created));
  return true;
}

/* Helper functions for mmo_decide_section, used through
   bfd_map_over_sections.  */

static void
mmo_find_sec_w_addr (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *p)
{
  struct mmo_find_sec_info *infop = (struct mmo_find_sec_info *) p;
  bfd_vma vma = bfd_section_vma (sec);

  /* Ignore sections that aren't loaded.  */
  if ((bfd_section_flags (sec) & (SEC_LOAD | SEC_ALLOC))
      !=  (SEC_LOAD | SEC_ALLOC))
    return;

  if (infop->addr >= vma && infop->addr < vma + sec->size)
    infop->sec = sec;
}

static void
mmo_find_sec_w_addr_grow (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *p)
{
  struct mmo_find_sec_info *infop = (struct mmo_find_sec_info *) p;
  bfd_vma vma = bfd_section_vma (sec);

  /* Ignore sections that aren't loaded.  */
  if ((bfd_section_flags (sec) & (SEC_LOAD | SEC_ALLOC))
      !=  (SEC_LOAD | SEC_ALLOC))
    return;

  if (infop->addr >= vma && infop->addr < vma + MAX_ARTIFICIAL_SECTION_SIZE)
    infop->sec = sec;
}

/* Find a section that corresponds to a VMA.  Automatically create .text
   or .data and set current section to it, depending on what vma.  If we
   can't deduce a section, make one up as ".MMIX.sec.N", where N is an
   increasing number.  */

static asection *
mmo_decide_section (bfd *abfd, bfd_vma vma)
{
  asection *sec = NULL;
  char sec_name[sizeof (".MMIX.sec.") + 20];
  struct mmo_find_sec_info info;

  info.addr = vma;
  info.sec = NULL;

  /* First see if there's a section that would match exactly.  */
  bfd_map_over_sections (abfd, mmo_find_sec_w_addr, &info);

  if (info.sec != NULL)
    return info.sec;

  /* If there's no such section, try and expand one of the existing ones,
     up to a limit.  Make sure we have .text and .data before we try that;
     create them corresponding to expected addresses and set flags to make
     them match the "loaded and with contents" expectation.  */
  if ((vma >> 56) == 0)
    {
      sec = bfd_make_section_old_way (abfd, MMO_TEXT_SECTION_NAME);

      if (sec == NULL)
	return NULL;

      if (!sec->user_set_vma && !bfd_set_section_vma (sec, vma))
	return NULL;

      if (!bfd_set_section_flags (sec, (bfd_section_flags (sec)
					| SEC_CODE | SEC_LOAD | SEC_ALLOC)))
	return NULL;
    }
  else if ((vma >> 56) == 0x20)
    {
      sec = bfd_make_section_old_way (abfd, MMO_DATA_SECTION_NAME);

      if (sec == NULL)
	return NULL;

      if (!sec->user_set_vma && !bfd_set_section_vma (sec, vma))
	return NULL;

      if (!bfd_set_section_flags (sec, (bfd_section_flags (sec)
					| SEC_LOAD | SEC_ALLOC)))
	return NULL;
    }

  bfd_map_over_sections (abfd, mmo_find_sec_w_addr_grow, &info);

  if (info.sec != NULL)
    return info.sec;

  /* If there's still no suitable section, make a new one.  */
  sprintf (sec_name, ".MMIX.sec.%d", abfd->tdata.mmo_data->sec_no++);
  sec = mmo_make_section (abfd, sec_name);

  if (!sec || (!sec->user_set_vma && !bfd_set_section_vma (sec, vma)))
    return NULL;

  if (!bfd_set_section_flags (sec, (bfd_section_flags (sec)
				    | SEC_LOAD | SEC_ALLOC)))
    return NULL;
  return sec;
}

/* Xor in a 64-bit value VALUE at VMA.  */

static inline bfd_byte *
mmo_xore_64 (asection *sec, bfd_vma vma, bfd_vma value)
{
  bfd_byte *loc = mmo_get_loc (sec, vma, 8);
  if (loc)
    {
      bfd_vma prev = bfd_get_64 (sec->owner, loc);

      value ^= prev;
      bfd_put_64 (sec->owner, value, loc);
    }
  return loc;
}

/* Xor in a 32-bit value VALUE at VMA.  */

static inline bfd_byte *
mmo_xore_32 (asection *sec, bfd_vma vma, unsigned int value)
{
  bfd_byte *loc = mmo_get_loc (sec, vma, 4);
  if (loc)
    {
      unsigned int prev = bfd_get_32 (sec->owner, loc);

      value ^= prev;
      bfd_put_32 (sec->owner, value, loc);
    }
  return loc;
}

/* Xor in a 16-bit value VALUE at VMA.  */

static inline bfd_byte *
mmo_xore_16 (asection *sec, bfd_vma vma, unsigned int value)
{
  bfd_byte *loc = mmo_get_loc (sec, vma, 2);
  if (loc)
    {
      unsigned int prev = bfd_get_16 (sec->owner, loc);

      value ^= prev;
      bfd_put_16 (sec->owner, value, loc);
    }
  return loc;
}

/* Write a 32-bit word to output file, no lop_quote generated.  */

static inline void
mmo_write_tetra_raw (bfd *abfd, unsigned int value)
{
  bfd_byte buf[4];

  bfd_put_32 (abfd, value, buf);

  if (bfd_write (buf, 4, abfd) != 4)
    abfd->tdata.mmo_data->have_error = true;
}

/* Write a 32-bit word to output file; lop_quote if necessary.  */

static inline void
mmo_write_tetra (bfd *abfd, unsigned int value)
{
  if (((value >> 24) & 0xff) == LOP)
    mmo_write_tetra_raw (abfd, LOP_QUOTE_NEXT);

  mmo_write_tetra_raw (abfd, value);
}

/* Write a 64-bit word to output file, perhaps with lop_quoting.  */

static inline void
mmo_write_octa (bfd *abfd, bfd_vma value)
{
  mmo_write_tetra (abfd, (unsigned int) (value >> 32));
  mmo_write_tetra (abfd, (unsigned int) value);
}

/* Write a 64-bit word to output file, without lop_quoting.  */

static inline void
mmo_write_octa_raw (bfd *abfd, bfd_vma value)
{
  mmo_write_tetra_raw (abfd, (unsigned int) (value >> 32));
  mmo_write_tetra_raw (abfd, (unsigned int) value);
}

/* Write quoted contents.  Intended to be called multiple times in
   sequence, followed by a call to mmo_flush_chunk.  */

static inline bool
mmo_write_chunk (bfd *abfd, const bfd_byte *loc, unsigned int len)
{
  bool retval = true;
  struct mmo_data_struct *mmop = abfd->tdata.mmo_data;

  /* Fill up a tetra from bytes remaining from a previous chunk.  */
  if (mmop->byte_no != 0)
    {
      while (mmop->byte_no < 4 && len != 0)
	{
	  mmop->buf[mmop->byte_no++] = *loc++;
	  len--;
	}

      if (mmop->byte_no == 4)
	{
	  mmo_write_tetra (abfd, bfd_get_32 (abfd, mmop->buf));
	  mmop->byte_no = 0;
	}
    }

  while (len >= 4)
    {
      if (loc[0] == LOP)
	mmo_write_tetra_raw (abfd, LOP_QUOTE_NEXT);

      retval = (retval
		&& ! mmop->have_error
		&& 4 == bfd_write (loc, 4, abfd));

      loc += 4;
      len -= 4;
    }

  if (len)
    {
      /* We must have flushed a previous remainder if we get one from
	 this chunk too.  */
      BFD_ASSERT (mmop->byte_no == 0);
      memcpy (mmop->buf, loc, len);
      mmop->byte_no = len;
    }

  if (! retval)
    mmop->have_error = true;
  return retval;
}

/* Flush remaining bytes, from a previous mmo_write_chunk, zero-padded to
   4 bytes.  */

static inline bool
mmo_flush_chunk (bfd *abfd)
{
  if (abfd->tdata.mmo_data->byte_no != 0)
    {
      memset (abfd->tdata.mmo_data->buf + abfd->tdata.mmo_data->byte_no,
	      0, 4 - abfd->tdata.mmo_data->byte_no);
      mmo_write_tetra (abfd,
		       bfd_get_32 (abfd, abfd->tdata.mmo_data->buf));
      abfd->tdata.mmo_data->byte_no = 0;
    }

  return ! abfd->tdata.mmo_data->have_error;
}

/* Same, but from a list.  */

static inline bool
mmo_write_chunk_list (bfd *abfd, mmo_data_list_type *datap)
{
  for (; datap != NULL; datap = datap->next)
    if (! mmo_write_chunk (abfd, datap->data, datap->size))
      return false;

  return mmo_flush_chunk (abfd);
}

/* Write a lop_loc and some contents.  A caller needs to call
   mmo_flush_chunk after calling this function.  The location is only
   output if different than *LAST_VMAP, which is updated after this call.  */

static bool
mmo_write_loc_chunk (bfd *abfd, bfd_vma vma, const bfd_byte *loc,
		     unsigned int len, bfd_vma *last_vmap)
{
  /* Find an initial and trailing section of zero (aligned) tetras; we don't
     need to write out zeros.  FIXME: When we do this, we should emit
     section size and address specifiers, else objcopy can't always perform
     an identity translation.  Only do this if we *don't* have left-over
     data from a previous write (and will not add any) or else the vma of
     this chunk is *not* the next address, because then data isn't
     tetrabyte-aligned and we're concatenating to that left-over data.  */

  if ((vma & 3) == 0
      && (abfd->tdata.mmo_data->byte_no == 0 || vma != *last_vmap))
    {
      while (len > 4 && bfd_get_32 (abfd, loc) == 0)
	{
	  vma += 4;
	  len -= 4;
	  loc += 4;
	}

      if ((len & 3) == 0)
	while (len > 4 && bfd_get_32 (abfd, loc + len - 4) == 0)
	  len -= 4;
    }

  /* Only write out the location if it's different than the one the caller
     (supposedly) previously handled, accounting for omitted leading zeros.  */
  if (vma != *last_vmap)
    {
      /* We might be in the middle of a sequence.  */
      mmo_flush_chunk (abfd);

      /* This should not happen during normal usage, but can presumably
	 happen with an erroneous linker-script, so handle gracefully.
	 Avoid Knuth-specific terms in the message, such as "tetrabyte".
	 Note that this function will get non-4-multiple lengths and
	 unaligned vmas but those come in tuples (mostly pairs) and are
	 continuous (i.e. the if-condition above false) and they are
	 group-wise aligned.  */
      if ((vma & 3) != 0)
	{
	  _bfd_error_handler
	    /* xgettext:c-format */
	    (_("%pB: attempt to emit contents at non-multiple-of-4"
	       " address %#" PRIx64 ""),
	     abfd, (uint64_t) vma);
	  bfd_set_error (bfd_error_bad_value);
	  return false;
	}

      /* We always write the location as 64 bits; no use saving bytes
	 here.  */
      mmo_write_tetra_raw (abfd, (LOP << 24) | (LOP_LOC << 16) | 2);
      mmo_write_octa_raw (abfd, vma);
    }

  /* Update to reflect end of this chunk, with trailing zeros omitted.  */
  *last_vmap = vma + len;

  return (! abfd->tdata.mmo_data->have_error
	  && mmo_write_chunk (abfd, loc, len));
}

/* Same, but from a list.  */

static inline bool
mmo_write_loc_chunk_list (bfd *abfd, mmo_data_list_type *datap)
{
  /* Get an address different than the address of the first chunk.  */
  bfd_vma last_vma = datap ? datap->where - 1 : 0;

  for (; datap != NULL; datap = datap->next)
    if (! mmo_write_loc_chunk (abfd, datap->where, datap->data, datap->size,
			       &last_vma))
      return false;

  return mmo_flush_chunk (abfd);
}

/* Make a .MMIX.spec_data.N section.  */

static asection *
mmo_get_generic_spec_data_section (bfd *abfd, int spec_data_number)
{
  asection *sec;
  char secname[sizeof (MMIX_OTHER_SPEC_SECTION_PREFIX) + 20]
    = MMIX_OTHER_SPEC_SECTION_PREFIX;

  sprintf (secname + strlen (MMIX_OTHER_SPEC_SECTION_PREFIX),
	   "%d", spec_data_number);

  sec = mmo_make_section (abfd, secname);

  return sec;
}

/* Make a special section for SPEC_DATA_NUMBER.  If it is the one we use
   ourselves, parse some of its data to get at the section name.  */

static asection *
mmo_get_spec_section (bfd *abfd, int spec_data_number)
{
  char *secname;
  asection *sec;
  bfd_byte buf[4];
  unsigned int secname_length;
  unsigned int i;
  bfd_vma section_length;
  bfd_vma section_vma;
  mmo_data_list_type *loc;
  flagword flags;
  long orig_pos;

  /* If this isn't the "special" special data, then make a placeholder
     section.  */
  if (spec_data_number != SPEC_DATA_SECTION)
    return mmo_get_generic_spec_data_section (abfd, spec_data_number);

  /* Seek back to this position if there was a format error.  */
  orig_pos = bfd_tell (abfd);

  /* Read the length (in 32-bit words).  */
  if (bfd_read (buf, 4, abfd) != 4)
    goto format_error;

  if (buf[0] == LOP)
    {
      if (buf[1] != LOP_QUOTE)
	goto format_error;

      if (bfd_read (buf, 4, abfd) != 4)
	goto format_error;
    }

  /* We don't care to keep the name length accurate.  It's
     zero-terminated.  */
  secname_length = bfd_get_32 (abfd, buf) * 4;

  /* Check section name length for sanity.  */
  if (secname_length > MAX_SECTION_NAME_SIZE)
    goto format_error;

  /* This should be free'd regardless if a section is created.  */
  secname = bfd_malloc (secname_length + 1);
  secname[secname_length] = 0;

  for (i = 0; i < secname_length / 4; i++)
    {
      if (bfd_read (secname + i * 4, 4, abfd) != 4)
	goto format_error_free;

      if (secname[i * 4] == (char) LOP)
	{
	  /* A bit of overkill, but we handle char 0x98 in a section name,
	     and recognize misparsing.  */
	  if (secname[i * 4 + 1] != LOP_QUOTE
	      || bfd_read (secname + i * 4, 4, abfd) != 4)
	    /* Whoops.  We thought this was a name, and now we found a
	       non-lop_quote lopcode before we parsed the whole length of
	       the name.  Signal end-of-file in the same manner.  */
	      goto format_error_free;
	}
    }

  /* Get the section flags.  */
  if (bfd_read (buf, 4, abfd) != 4
      || (buf[0] == LOP
	  && (buf[1] != LOP_QUOTE || bfd_read (buf, 4, abfd) != 4)))
    goto format_error_free;

  flags = bfd_get_32 (abfd, buf);

  /* Get the section length.  */
  if (bfd_read (buf, 4, abfd) != 4
      || (buf[0] == LOP
	  && (buf[1] != LOP_QUOTE || bfd_read (buf, 4, abfd) != 4)))
    goto format_error_free;

  section_length = (bfd_vma) bfd_get_32 (abfd, buf) << 32;

  /* That's the first, high-part.  Now get the low part.  */

  if (bfd_read (buf, 4, abfd) != 4
      || (buf[0] == LOP
	  && (buf[1] != LOP_QUOTE || bfd_read (buf, 4, abfd) != 4)))
    goto format_error_free;

  section_length |= (bfd_vma) bfd_get_32 (abfd, buf);

  /* Check the section length for sanity.  */
  if (section_length > MAX_ARTIFICIAL_SECTION_SIZE)
    goto format_error_free;

  /* Get the section VMA.  */
  if (bfd_read (buf, 4, abfd) != 4
      || (buf[0] == LOP
	  && (buf[1] != LOP_QUOTE || bfd_read (buf, 4, abfd) != 4)))
    goto format_error_free;

  section_vma = (bfd_vma) bfd_get_32 (abfd, buf) << 32;

  /* That's the first, high-part.  Now get the low part.  */
  if (bfd_read (buf, 4, abfd) != 4
      || (buf[0] == LOP
	  && (buf[1] != LOP_QUOTE || bfd_read (buf, 4, abfd) != 4)))
    goto format_error_free;

  section_vma |= (bfd_vma) bfd_get_32 (abfd, buf);

  sec = mmo_make_section (abfd, secname);
  free (secname);
  if (sec == NULL)
    goto format_error;

  /* We allocate a buffer here for the advertised size, with head room for
     tetrabyte alignment.  */
  loc = bfd_zalloc (abfd, (section_length + 3
			   + sizeof (struct mmo_data_list_struct)));
  if (loc == NULL)
    goto format_error;

  /* Use a TETRA-rounded size for the allocated buffer; we set the
     "visible" section size below.  */
  loc->size = (section_length + 3) & ~3;

  /* Add in the section flags we found to those bfd entered during this
     process and set the contents.  */
  if (!bfd_set_section_flags (sec,
			      (bfd_sec_flags_from_mmo_flags (flags)
			       | bfd_section_flags (sec)
			       | (section_length != 0 ? SEC_HAS_CONTENTS : 0)))
      || !bfd_set_section_size (sec, sec->size + section_length)
      /* Set VMA only for the first occurrence.  */
      || (!sec->user_set_vma && !bfd_set_section_vma (sec, section_vma)))
    {
      /* If we get an error for any of the calls above, signal more than
	 just a format error for the spec section.  */
      return NULL;
    }

  loc->next = NULL;
  if (mmo_section_data (sec)->tail != NULL)
    mmo_section_data (sec)->tail->next = loc;
  else
    mmo_section_data (sec)->head = loc;
  mmo_section_data (sec)->tail = loc;
  loc->where = section_vma;

  return sec;

 format_error_free:
  free (secname);
 format_error:
  if (bfd_seek (abfd, orig_pos, SEEK_SET) != 0)
    return NULL;

  return mmo_get_generic_spec_data_section (abfd, spec_data_number);
}

/* Read a byte, but read from file in multiples of 32-bit words.  */

static bfd_byte
mmo_get_byte (bfd *abfd)
{
  bfd_byte retval;

  if (abfd->tdata.mmo_data->byte_no == 0)
    {
      if (!abfd->tdata.mmo_data->have_error
	  && bfd_read (abfd->tdata.mmo_data->buf, 4, abfd) != 4)
	abfd->tdata.mmo_data->have_error = true;

      /* A value somewhat safe against tripping on some inconsistency
	 when mopping up after this error.  */
      if (abfd->tdata.mmo_data->have_error)
	return 128;
    }

  retval = abfd->tdata.mmo_data->buf[abfd->tdata.mmo_data->byte_no];
  abfd->tdata.mmo_data->byte_no = (abfd->tdata.mmo_data->byte_no + 1) % 4;

  return retval;
}

/* Write a byte, in multiples of 32-bit words.  */

static void
mmo_write_byte (bfd *abfd, bfd_byte value)
{
  abfd->tdata.mmo_data->buf[(abfd->tdata.mmo_data->byte_no++ % 4)] = value;
  if ((abfd->tdata.mmo_data->byte_no % 4) == 0)
    {
      if (! abfd->tdata.mmo_data->have_error
	  && bfd_write (abfd->tdata.mmo_data->buf, 4, abfd) != 4)
	abfd->tdata.mmo_data->have_error = true;
    }
}

/* Create a symbol.  */

static bool
mmo_create_symbol (bfd *abfd, const char *symname, bfd_vma addr, enum
		   mmo_sym_type sym_type, unsigned int serno)
{
  struct mmo_symbol *n;

  n = (struct mmo_symbol *) bfd_alloc (abfd, sizeof (struct mmo_symbol));
  if (n == NULL)
    return false;

  n->name = bfd_alloc (abfd, strlen (symname) + 1);
  if (n->name == NULL)
    return false;

  strcpy (n->name, symname);

  n->value = addr;
  n->sym_type = sym_type;
  n->serno = serno;

  if (abfd->tdata.mmo_data->symbols == NULL)
    abfd->tdata.mmo_data->symbols = n;
  else
    abfd->tdata.mmo_data->symtail->next = n;
  abfd->tdata.mmo_data->symtail = n;
  n->next = NULL;

  ++abfd->symcount;

  /* Check that :Main equals the last octa of the .MMIX.reg_contents
     section, as it's the one place we're sure to pass when reading a mmo
     object.  For written objects, we do it while setting the symbol
     table.  */
  if (strcmp (symname, MMIX_START_SYMBOL_NAME) == 0
      && bfd_get_start_address (abfd) != addr
      && !mmo_ignore_symbol_consistency (abfd))
    {
      _bfd_error_handler
	(_("%pB: invalid mmo file: initialization value for $255"
	   " is not `Main'\n"),
	 abfd);
      bfd_set_error (bfd_error_bad_value);
      return false;
    }

  return true;
}

/* Read in symbols.  */

static bool
mmo_get_symbols (bfd *abfd)
{
/*
INODE
Symbol-table, mmo section mapping, File layout, mmo
SUBSECTION
	Symbol table format

	From mmixal.w (or really, the generated mmixal.tex) in the
	MMIXware package which also contains the @command{mmix} simulator:
	``Symbols are stored and retrieved by means of a @samp{ternary
	search trie}, following ideas of Bentley and Sedgewick. (See
	ACM--SIAM Symp.@: on Discrete Algorithms @samp{8} (1997), 360--369;
	R.@:Sedgewick, @samp{Algorithms in C} (Reading, Mass.@:
	Addison--Wesley, 1998), @samp{15.4}.)  Each trie node stores a
	character, and there are branches to subtries for the cases where
	a given character is less than, equal to, or greater than the
	character in the trie.  There also is a pointer to a symbol table
	entry if a symbol ends at the current node.''

	So it's a tree encoded as a stream of bytes.  The stream of bytes
	acts on a single virtual global symbol, adding and removing
	characters and signalling complete symbol points.  Here, we read
	the stream and create symbols at the completion points.

	First, there's a control byte <<m>>.  If any of the listed bits
	in <<m>> is nonzero, we execute what stands at the right, in
	the listed order:

| (MMO3_LEFT)
| 0x40 - Traverse left trie.
|        (Read a new command byte and recurse.)
|
| (MMO3_SYMBITS)
| 0x2f - Read the next byte as a character and store it in the
|        current character position; increment character position.
|        Test the bits of <<m>>:
|
|        (MMO3_WCHAR)
|        0x80 - The character is 16-bit (so read another byte,
|               merge into current character.
|
|        (MMO3_TYPEBITS)
|        0xf  - We have a complete symbol; parse the type, value
|               and serial number and do what should be done
|               with a symbol.  The type and length information
|               is in j = (m & 0xf).
|
|               (MMO3_REGQUAL_BITS)
|	        j == 0xf: A register variable.  The following
|                         byte tells which register.
|               j <= 8:   An absolute symbol.  Read j bytes as the
|                         big-endian number the symbol equals.
|                         A j = 2 with two zero bytes denotes an
|                         unknown symbol.
|               j > 8:    As with j <= 8, but add (0x20 << 56)
|                         to the value in the following j - 8
|                         bytes.
|
|               Then comes the serial number, as a variant of
|               uleb128, but better named ubeb128:
|               Read bytes and shift the previous value left 7
|               (multiply by 128).  Add in the new byte, repeat
|               until a byte has bit 7 set.  The serial number
|               is the computed value minus 128.
|
|        (MMO3_MIDDLE)
|        0x20 - Traverse middle trie.  (Read a new command byte
|               and recurse.)  Decrement character position.
|
| (MMO3_RIGHT)
| 0x10 - Traverse right trie.  (Read a new command byte and
|        recurse.)

	Let's look again at the <<lop_stab>> for the trivial file
	(@pxref{File layout}).

| 0x980b0000 - lop_stab for ":Main" = 0, serial 1.
| 0x203a4040
| 0x10404020
| 0x4d206120
| 0x69016e00
| 0x81000000

	This forms the trivial trie (note that the path between ``:'' and
	``M'' is redundant):

| 203a	   ":"
| 40       /
| 40      /
| 10      \
| 40      /
| 40     /
| 204d  "M"
| 2061  "a"
| 2069  "i"
| 016e  "n" is the last character in a full symbol, and
|       with a value represented in one byte.
| 00    The value is 0.
| 81    The serial number is 1.  */

  bfd_byte m = mmo_get_byte (abfd);

  /* Check first if we have a bad hair day.  */
  if (abfd->tdata.mmo_data->have_error)
    return false;

  if (m & MMO3_LEFT)
    /* Traverse left trie. */
    mmo_get_symbols (abfd);

  if (m & MMO3_SYMBITS)
    {
      bfd_byte c = mmo_get_byte (abfd);
      bfd_byte j = m & MMO3_TYPEBITS;
      bfd_vma addr = 0;
      enum mmo_sym_type sym_type;
      unsigned int serno = 0;
      bfd_byte k;

      if (m & MMO3_WCHAR)
	{
	  bfd_byte c2 = mmo_get_byte (abfd);

	  /* A two-byte character.  We can't grok this, but neither can
	     mmotype, for other cases than the second byte being zero.  */

	  if (c != 0)
	    {
	      abfd->tdata.mmo_data->lop_stab_symbol
		[abfd->tdata.mmo_data->symbol_position] = 0;

	      _bfd_error_handler
		/* xgettext:c-format */
		(_("%pB: unsupported wide character sequence"
		   " 0x%02X 0x%02X after symbol name starting with `%s'\n"),
		 abfd, c, c2, abfd->tdata.mmo_data->lop_stab_symbol);
	      bfd_set_error (bfd_error_bad_value);
	      abfd->tdata.mmo_data->have_error = true;
	      return false;
	    }
	  else
	    c = c2;
	}

      if (abfd->tdata.mmo_data->symbol_position
	  >= abfd->tdata.mmo_data->max_symbol_length)
	{
	  _bfd_error_handler
	    /* xgettext:c-format */
	    (_("%pB: symbol name exceeds given max length of %d"),
	     abfd, abfd->tdata.mmo_data->max_symbol_length);
	  abfd->tdata.mmo_data->have_error = true;
	  return false;
	}
      abfd->tdata.mmo_data->lop_stab_symbol[abfd->tdata.mmo_data->symbol_position++] = c;
      abfd->tdata.mmo_data->lop_stab_symbol[abfd->tdata.mmo_data->symbol_position] = 0;

      if (j & MMO3_REGQUAL_BITS)
	{
	  if (j == MMO3_REGQUAL_BITS)
	    {
	      sym_type = mmo_reg_sym;
	      addr = mmo_get_byte (abfd);
	    }
	  else if (j <= 8)
	    {
	      unsigned int i;

	      for (i = 0; i < j; i++)
		addr = (addr << 8) + mmo_get_byte (abfd);

	      if (addr == 0 && j == MMO3_UNDEF)
		sym_type = mmo_undef_sym;
	      else
		sym_type = mmo_abs_sym;
	    }
	  else
	    {
	      unsigned int i;

	      for (i = MMO3_DATA; i < j; i++)
		addr = (addr << 8) + mmo_get_byte (abfd);

	      addr += (bfd_vma) 0x20 << 56;
	      sym_type = mmo_data_sym;
	    }

	  /* Get the serial number.  */
	  do
	    {
	      k = mmo_get_byte (abfd);
	      serno = (serno << 7) + k;
	    }
	  while (k < 128);
	  serno -= 128;

	  /* Got it.  Now enter it.  Skip a leading ":".  */
	  if (! abfd->tdata.mmo_data->have_error
	      && ! mmo_create_symbol (abfd,
				      abfd->tdata.mmo_data->lop_stab_symbol
				      + 1,
				      addr, sym_type, serno))
	    abfd->tdata.mmo_data->have_error = true;
	}

      if (m & MMO3_MIDDLE)
	/* Traverse middle trie. */
	mmo_get_symbols (abfd);

      abfd->tdata.mmo_data->symbol_position--;
    }

  if (m & MMO3_RIGHT)
    /* Traverse right trie.  */
    mmo_get_symbols (abfd);

  return ! abfd->tdata.mmo_data->have_error;
}

/* Get the location of memory area [VMA..VMA + SIZE - 1], which we think
   is in section SEC.  Adjust and reallocate zero-initialized contents.
   If there's new contents, allocate to the next multiple of
   MMO_SEC_CONTENTS_CHUNK_SIZE.  */

static bfd_byte *
mmo_get_loc (asection *sec, bfd_vma vma, unsigned int size)
{
  bfd_size_type allocated_size;
  struct mmo_section_data_struct *sdatap = mmo_section_data (sec);
  struct mmo_data_list_struct *datap = sdatap->head;
  struct mmo_data_list_struct *entry;

  /* First search the list to see if we have the requested chunk in one
     piece, or perhaps if we have a suitable chunk with room to fit.  */
  for (; datap != NULL; datap = datap->next)
    {
      if (datap->where <= vma
	  && datap->size >= size
	  && datap->size - size >= vma - datap->where)
	return datap->data + (vma - datap->where);
      else if (datap->where <= vma
	       && datap->allocated_size >= size
	       && datap->allocated_size - size >= vma - datap->where
	       /* Only munch on the "allocated size" if it does not
		  overlap the next chunk.  */
	       && (datap->next == NULL || datap->next->where >= vma + size))
	{
	  /* There was room allocated, but the size wasn't set to include
	     it.  Do that now.  */
	  datap->size = vma - datap->where + size;

	  /* Update the section size.  This happens only if we update the
	     32-bit-aligned chunk size.  Callers that have
	     non-32-bit-aligned sections should do all allocation and
	     size-setting by themselves or at least set the section size
	     after the last allocating call to this function.  */
	  if (vma - sec->vma + size > sec->size)
	    sec->size = vma - sec->vma + size;

	  return datap->data + (vma - datap->where);
	}
    }

  /* Not found; allocate a new block.  First check in case we get a
     request for a size split up over several blocks; we'll have to return
     NULL for those cases, requesting the caller to split up the request.
     Requests with an address aligned on MMO_SEC_CONTENTS_CHUNK_SIZE bytes and
     for no more than MMO_SEC_CONTENTS_CHUNK_SIZE will always get resolved.  */

  for (datap = sdatap->head; datap != NULL; datap = datap->next)
    if ((datap->where <= vma && datap->size > vma - datap->where)
	|| (datap->where < vma + size
	    && datap->where + datap->size >= vma + size))
      return NULL;

  allocated_size
    = (size + MMO_SEC_CONTENTS_CHUNK_SIZE - 1) & ~(MMO_SEC_CONTENTS_CHUNK_SIZE - 1);
  entry = (mmo_data_list_type *)
    bfd_zalloc (sec->owner, sizeof (mmo_data_list_type) + allocated_size);
  if (entry == NULL)
    return NULL;
  entry->where = vma;
  entry->size = size;
  entry->allocated_size = allocated_size;

  datap = sdatap->head;

  /* Sort the records by address.  Optimize for the common case of adding
     a record to the end of the list.  */
  if (sdatap->tail != NULL && entry->where >= sdatap->tail->where)
    {
      sdatap->tail->next = entry;
      entry->next = NULL;
      sdatap->tail = entry;
    }
  else
    {
      mmo_data_list_type **look;
      for (look = &sdatap->head;
	   *look != NULL && (*look)->where < entry->where;
	   look = &(*look)->next)
	;
      entry->next = *look;
      *look = entry;
      if (entry->next == NULL)
	{
	  sdatap->tail = entry;

	  /* We get here for the first time (at other times too) for this
	     section.  Say we have contents.  */
	  if (!bfd_set_section_flags (sec, (bfd_section_flags (sec)
					    | SEC_HAS_CONTENTS)))
	    return NULL;
	}
    }

  /* Update the section size.  This happens only when we add contents and
     re-size as we go.  The section size will then be aligned to 32 bits.  */
  if (vma - sec->vma + size > sec->size)
    sec->size = vma - sec->vma + size;
  return entry->data;
}

/* Set sizes once we've read in all sections.  */

static void
mmo_map_set_sizes (bfd *abfd ATTRIBUTE_UNUSED, asection *sec,
		   void *ignored ATTRIBUTE_UNUSED)
{
  sec->lma = sec->vma;
}

/* Read the mmo file and turn it into sections.  */

static bool
mmo_scan (bfd *abfd)
{
  unsigned int i;
  unsigned int lineno ATTRIBUTE_UNUSED = 1;
  bool error = false;
  bfd_vma vma = 0;
  asection *sec = NULL;
  asection *non_spec_sec = NULL;
  bfd_vma non_spec_vma = 0;
  bfd_size_type nbytes_read = 0;
  /* Buffer with room to read a 64-bit value.  */
  bfd_byte buf[8];
  file_ptr stab_loc = -1;
  char *file_names[256];

  abfd->symcount = 0;
  memset (file_names, 0, sizeof (file_names));

  if (bfd_seek (abfd, 0, SEEK_SET) != 0)
    goto error_return;

  while ((nbytes_read = bfd_read (buf, 4, abfd)) == 4)
    {
      if (buf[0] == LOP)
	{
	  unsigned int y = bfd_get_8 (abfd, buf + 2);
	  unsigned int z = bfd_get_8 (abfd, buf + 3);

	  /* Change back to the original section for lopcodes other
	     than LOP_QUOTE that comes after a LOP_SPEC.  */
	  if ((buf[1] != LOP_QUOTE || y != 0 || z != 1)
	      && non_spec_sec != NULL)
	    {
	      sec = non_spec_sec;
	      vma = non_spec_vma;
	      non_spec_sec = NULL;
	    }

	  switch (buf[1])
	    {
	    default:
	      _bfd_error_handler
		/* xgettext:c-format */
		(_("%pB: invalid mmo file: unsupported lopcode `%d'\n"),
		 abfd, buf[1]);
	      bfd_set_error (bfd_error_bad_value);
	      goto error_return;

	    case LOP_QUOTE:
	      /* Quote the next 32-bit word.  */
	      if (y != 0 || z != 1)
		{
		  _bfd_error_handler
		    /* xgettext:c-format */
		    (_("%pB: invalid mmo file: expected YZ = 1"
		       " got YZ = %d for lop_quote\n"),
		     abfd, y*256+z);
		  bfd_set_error (bfd_error_bad_value);
		  goto error_return;
		}
	      if (bfd_read (buf, 4, abfd) != 4)
		goto error_return;

	      vma &= ~3;
	      if (sec == NULL)
		sec = bfd_make_section_old_way (abfd, MMO_TEXT_SECTION_NAME);
	      if (!mmo_xore_32 (sec, vma, bfd_get_32 (abfd, buf)))
		{
		  bfd_set_error (bfd_error_bad_value);
		  goto error_return;
		}
	      vma += 4;
	      lineno++;
	      break;

	    case LOP_LOC:
	      /* Set vma (and section).  */
	      vma = (bfd_vma) y << 56;
	      if (z == 1)
		{
		  /* Get a 32-bit value.  */
		  if (bfd_read (buf, 4, abfd) != 4)
		    goto error_return;

		  vma += bfd_get_32 (abfd, buf);
		}
	      else if (z == 2)
		{
		  /* Get a 64-bit value.  */
		  if (bfd_read (buf, 8, abfd) != 8)
		    goto error_return;

		  vma += bfd_get_64 (abfd, buf);
		}
	      else
		{
		  _bfd_error_handler
		    /* xgettext:c-format */
		    (_("%pB: invalid mmo file: expected z = 1 or z = 2,"
		       " got z = %d for lop_loc\n"),
		     abfd, z);
		  bfd_set_error (bfd_error_bad_value);
		  goto error_return;
		}

	      /* When we decide which section the data goes into, we might
		 create the section.  If that happens, make sure the VMA at
		 creation time is tetra-aligned.  */
	      sec = mmo_decide_section (abfd, vma & ~3);
	      if (sec == NULL)
		goto error_return;
	      break;

	    case LOP_SKIP:
	      /* Move forward within the same section.  */
	      vma += y * 256 + z;

	      sec = mmo_decide_section (abfd, vma);
	      if (sec == NULL)
		goto error_return;
	      break;

	    case LOP_FIXO:
	      /* A fixup: Store the current vma somewhere.  Position using
		 same format as LOP_LOC.  */
	      {
		bfd_vma p = (bfd_vma) y << 56;
		asection *fixosec;

		if (z == 1)
		  {
		    /* Get a 32-bit value.  */
		    if (bfd_read (buf, 4, abfd) != 4)
		      goto error_return;

		    p += bfd_get_32 (abfd, buf);
		  }
		else if (z == 2)
		  {
		    /* Get a 64-bit value.  */
		    if (bfd_read (buf, 8, abfd) != 8)
		      goto error_return;

		    p += bfd_get_64 (abfd, buf);
		  }
		else
		  {
		    _bfd_error_handler
		      /* xgettext:c-format */
		      (_("%pB: invalid mmo file: expected z = 1 or z = 2,"
			 " got z = %d for lop_fixo\n"),
		       abfd, z);
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }

		/* The section where we store this address might be a
		   different one than the current section.  */
		fixosec = mmo_decide_section (abfd, p);
		if (fixosec == NULL)
		  goto error_return;
		if (!mmo_xore_64 (fixosec, p, vma))
		  {
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }
	      }
	    break;

	    case LOP_FIXR:
	      /* A fixup: Store YZ of this lopcode into YZ at vma - 4 * yz.  */
	      {
		unsigned int yz = (y * 256 + z);
		bfd_vma p = vma + 2 - 4 * yz;
		asection *fixrsec = mmo_decide_section (abfd, p);
		if (fixrsec == NULL)
		  goto error_return;
		if (!mmo_xore_16 (fixrsec, p, yz))
		  {
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }
	      }
	    break;

	    case LOP_FIXRX:
	      /* A fixup, similar to lop_fixr, but taking larger numbers
		 and can change branches into the opposite direction
		 (gasp!).  */
	      {
		bfd_vma delta;
		bfd_vma p;
		asection *fixrsec;

		if (y != 0)
		  {
		    _bfd_error_handler
		      /* xgettext:c-format */
		      (_("%pB: invalid mmo file: expected y = 0,"
			 " got y = %d for lop_fixrx\n"),
		       abfd, y);
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }

		if (z != 16 && z != 24)
		  {
		    _bfd_error_handler
		      /* xgettext:c-format */
		      (_("%pB: invalid mmo file: expected z = 16 or z = 24,"
			 " got z = %d for lop_fixrx\n"),
		       abfd, z);
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }

		/* Get the next 32-bit value.  */
		if (bfd_read (buf, 4, abfd) != 4)
		  goto error_return;

		delta = bfd_get_32 (abfd, buf);

		/* Do an, ehm, involved calculation for the location of
		   the fixup.  See mmixal documentation for a verbose
		   explanation.  We follow it verbosely here for the
		   readers delight.  */
		if (buf[0] == 0)
		  p = vma - 4 * delta;
		else if (buf[0] == 1)
		  p = vma - 4 * ((delta & 0xffffff) - (1 << z));
		else
		  {
		    _bfd_error_handler
		      /* xgettext:c-format */
		      (_("%pB: invalid mmo file: leading byte of operand word"
			 " must be 0 or 1, got %d for lop_fixrx\n"),
		       abfd, buf[0]);
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }

		fixrsec = mmo_decide_section (abfd, vma);
		if (fixrsec == NULL)
		  goto error_return;
		if (!mmo_xore_32 (fixrsec, p, delta))
		  {
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }
	      }
	    break;

	    case LOP_FILE:
	      /* Set current file and perhaps the file name.  Reset line
		 number.  */
	      if (z != 0)
		{
		  char *fname = bfd_malloc (z * 4 + 1);

		  if (fname == NULL)
		    {
		      _bfd_error_handler
			/* xgettext:c-format */
			(_("%pB: cannot allocate file name for file number %d,"
			   " %d bytes\n"),
			 abfd, y, z * 4 + 1);
		      bfd_set_error (bfd_error_system_call);
		      goto error_return;
		    }

		  fname[z * 4] = 0;

		  for (i = 0; i < z; i++)
		    {
		      if (bfd_read (fname + i * 4, 4, abfd) != 4)
			{
			  free (fname);
			  goto error_return;
			}
		    }

		  if (file_names[y] != NULL)
		    {
		      _bfd_error_handler
			/* xgettext:c-format */
			(_("%pB: invalid mmo file: file number %d `%s',"
			   " was already entered as `%s'\n"),
			 abfd, y, fname, file_names[y]);
		      bfd_set_error (bfd_error_bad_value);
		      free (fname);
		      goto error_return;
		    }

		  file_names[y] = fname;
		}

	      if (file_names[y] == NULL)
		{
		  _bfd_error_handler
		    /* xgettext:c-format */
		    (_("%pB: invalid mmo file: file name for number %d"
		       " was not specified before use\n"),
		     abfd, y);
		  bfd_set_error (bfd_error_bad_value);
		  goto error_return;
		}

	      lineno = 0;
	      break;

	    case LOP_LINE:
	      /* Set line number.  */
	      lineno = y * 256 + z;
	      /* FIXME: Create a sequence of mmo-specific line number
		 entries for each section, then translate into canonical
		 format.  */
	      break;

	    case LOP_SPEC:
	      /* Special data follows until the next non-lop_quote
		 lopcode.  */
	      non_spec_sec = sec;
	      non_spec_vma = vma;
	      sec = mmo_get_spec_section (abfd, y * 256 + z);
	      if (sec == NULL)
		goto error_return;

	      vma = sec->vma;
	      break;

	    case LOP_PRE:
	      {
		/* We ignore header information, except we read in the
		   creation time from the first 32-bit word with the time
		   in seconds since era.  */
		if (z >= 1
		    && bfd_read (abfd->tdata.mmo_data->created, 4,
				 abfd) != 4)
		  goto error_return;

		for (i = 1; i < z; i++)
		  if (bfd_read (buf, 4, abfd) != 4)
		    goto error_return;
	      }
	      break;

	    case LOP_POST:
	      /* This tells of the contents of registers $Z..$255 at
		 startup.  We make a section out of it, with VMA = Z * 8,
		 but only if Z != 255 or the contents is non-zero.  */
	      {
		asection *rsec;
		bfd_byte *loc;
		bfd_vma first_octa;
		bfd_vma startaddr_octa;

		/* Read first octaword outside loop to simplify logic when
		   excluding the Z == 255, octa == 0 case.  */
		if (bfd_read (buf, 8, abfd) != 8)
		  goto error_return;

		first_octa = bfd_get_64 (abfd, buf);

		/* Don't emit contents for the trivial case which is
		   always present; $255 pointing to Main.  */
		if (z != 255)
		  {
		    rsec
		      = bfd_make_section_old_way (abfd,
						  MMIX_REG_CONTENTS_SECTION_NAME);
		    rsec->flags |= SEC_LINKER_CREATED;
		    rsec->vma = z * 8;
		    loc = mmo_get_loc (rsec, z * 8, (255 - z) * 8);
		    if (!loc)
		      {
			bfd_set_error (bfd_error_bad_value);
			goto error_return;
		      }
		    bfd_put_64 (abfd, first_octa, loc);

		    for (i = z + 1; i < 255; i++)
		      {
			if (bfd_read (loc + (i - z) * 8, 8, abfd) != 8)
			  goto error_return;
		      }

		    /* Read out the last octabyte, and use it to set the
		       start address.  */
		    if (bfd_read (buf, 8, abfd) != 8)
		      goto error_return;

		    startaddr_octa = bfd_get_64 (abfd, buf);
		  }
		else
		  startaddr_octa = first_octa;

		if (! bfd_set_start_address (abfd, startaddr_octa))
		  {
		    /* Currently this can't fail, but this should handle
		       future failures.  */
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }
	      }
	      break;

	    case LOP_STAB:
	      /* We read in the symbols now, not later.  */
	      if (y != 0 || z != 0)
		{
		  _bfd_error_handler
		    /* xgettext:c-format */
		    (_("%pB: invalid mmo file: fields y and z of lop_stab"
		       " non-zero, y: %d, z: %d\n"),
		     abfd, y, z);
		  bfd_set_error (bfd_error_bad_value);
		  goto error_return;
		}

	      /* Save the location, so we can check that YZ in the LOP_END
		 is correct.  */
	      stab_loc = bfd_tell (abfd);

	      /* It's not said that an MMO can be without symbols (though
		 mmixal will refuse to assemble files without Main), but
		 it seems it would still be a valid mmo-file, so allow it.
		 We detect the absence of a symbol area in that the upper
		 limit is computed (from the lop_end YZ field) as 0.
		 Don't call mmo_get_symbols; it can only detect the end of
		 a valid symbol trie, not the absence of one.  */
	      if (abfd->tdata.mmo_data->max_symbol_length != 0
		  && ! mmo_get_symbols (abfd))
		goto error_return;
	      break;

	    case LOP_END:
	      {
		/* This must be the last 32-bit word in an mmo file.
		   Let's find out.  */
		struct stat statbuf;
		file_ptr curpos = bfd_tell (abfd);

		if (bfd_stat (abfd, &statbuf) < 0)
		  goto error_return;

		if (statbuf.st_size != curpos)
		  {
		    _bfd_error_handler
		      /* xgettext:c-format */
		      (_("%pB: invalid mmo file: lop_end not last item in"
			 " file\n"),
		       abfd);
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }

		/* Check that the YZ field is right.  Subtract the size of
		   this LOP_END in the calculation; YZ does not include
		   it.  */
		if ((long) (y * 256 + z) * 4 != (curpos - stab_loc) - 4)
		  {
		    _bfd_error_handler
		      /* xgettext:c-format */
		      (_("%pB: invalid mmo file: YZ of lop_end (%ld)"
			 " not equal to the number of tetras to the preceding"
			 " lop_stab (%ld)\n"),
		       abfd, (long) (y * 256 + z),
		       (long) (curpos - stab_loc - 4)/4);
		    bfd_set_error (bfd_error_bad_value);
		    goto error_return;
		  }

		bfd_map_over_sections (abfd, mmo_map_set_sizes, NULL);
		goto done;
	      }
	    }
	}
      else
	{
	  /* This wasn't a lopcode, so store it in the current section.  */
	  if (sec == NULL)
	    sec = bfd_make_section_old_way (abfd, MMO_TEXT_SECTION_NAME);
	  if (!mmo_xore_32 (sec, vma & ~3, bfd_get_32 (abfd, buf)))
	    {
	      bfd_set_error (bfd_error_bad_value);
	      goto error_return;
	    }
	  vma += 4;
	  vma &= ~3;
	  lineno++;
	}
    }

  /* We know this file is a multiple of four bytes (checked in
     mmo_object_p), so if we got something other than 0, this was a bad
     file (although it's more likely we'll get 0 in that case too).
     If we got end-of-file, then there was no lop_stab, so the file has
     invalid format.  */

  if (nbytes_read != 0)
    bfd_set_error (bfd_error_system_call);
  else
    bfd_set_error (bfd_error_bad_value);

 error_return:
  error = true;
 done:
  /* Mark the .text and .data section with their normal attribute if they
     contain anything.  This is not redundant wrt. mmo_decide_section,
     since that code might never execute, and conversely the alloc+code
     section flags must be set then.  */
  sec = bfd_get_section_by_name (abfd, MMO_TEXT_SECTION_NAME);
  if (sec != NULL
      && (bfd_section_flags (sec) & SEC_HAS_CONTENTS)
      && !bfd_set_section_flags (sec, (bfd_section_flags (sec)
				       | SEC_ALLOC | SEC_LOAD | SEC_CODE)))
    error = true;

  sec = bfd_get_section_by_name (abfd, MMO_DATA_SECTION_NAME);
  if (sec != NULL
      && (bfd_section_flags (sec) & SEC_HAS_CONTENTS)
      && !bfd_set_section_flags (sec, (bfd_section_flags (sec)
				       | SEC_ALLOC | SEC_LOAD | SEC_DATA)))
    error = true;

  /* Free whatever resources we took.  */
  for (i = 0; i < sizeof (file_names) / sizeof (file_names[0]); i++)
    free (file_names[i]);
  return ! error;
}

/* A hook to set up object file dependent section information.  For mmo,
   we point out the shape of allocated section contents.  */

static bool
mmo_new_section_hook (bfd *abfd, asection *newsect)
{
  if (!newsect->used_by_bfd)
    {
      /* We zero-fill all fields and assume NULL is represented by an all
	 zero-bit pattern.  */
      newsect->used_by_bfd
	= bfd_zalloc (abfd, sizeof (struct mmo_section_data_struct));
      if (!newsect->used_by_bfd)
	return false;
    }

  /* Always align to at least 32-bit words.  */
  newsect->alignment_power = 2;
  return _bfd_generic_new_section_hook (abfd, newsect);
}

/* We already have section contents loaded for sections that have
   contents.  */

static bool
mmo_get_section_contents (bfd *abfd ATTRIBUTE_UNUSED,
			  asection *sec,
			  void * location,
			  file_ptr offset,
			  bfd_size_type bytes_to_do)
{
  /* Iterate over diminishing chunk sizes, copying contents, like
     mmo_set_section_contents.  */
  while (bytes_to_do)
    {
      /* A minor song-and-dance to make sure we're not bitten by the
	 distant possibility of the cast from bfd_vma to int making the
	 chunk zero-sized.  */
      int chunk_size
	= (int) bytes_to_do != 0 ? bytes_to_do : MMO_SEC_CONTENTS_CHUNK_SIZE;
      bfd_byte *loc;

      do
	loc = mmo_get_loc (sec, sec->vma + offset, chunk_size);
      while (loc == NULL && (chunk_size /= 2) != 0);

      if (chunk_size == 0)
	return false;

      memcpy (location, loc, chunk_size);

      location = (bfd_byte *) location + chunk_size;
      bytes_to_do -= chunk_size;
      offset += chunk_size;
    }
  return true;
}

/* Return the amount of memory needed to read the symbol table.  */

static long
mmo_get_symtab_upper_bound (bfd *abfd)
{
  return (abfd->symcount + 1) * sizeof (asymbol *);
}

/* Sort mmo symbols by serial number.  */

static int
mmo_sort_mmo_symbols (const void *arg1, const void *arg2)
{
  const struct mmo_symbol *sym1 = *(const struct mmo_symbol **) arg1;
  const struct mmo_symbol *sym2 = *(const struct mmo_symbol **) arg2;

  /* Sort by serial number first.  */
  if (sym1->serno < sym2->serno)
    return -1;
  else if (sym1->serno > sym2->serno)
    return 1;

  /* Then sort by address of the table entries.  */
  return ((const char *) arg1 - (const char *) arg2);
}

/* Translate the symbol table.  */

static long
mmo_canonicalize_symtab (bfd *abfd, asymbol **alocation)
{
  unsigned int symcount = bfd_get_symcount (abfd);
  asymbol *csymbols;
  unsigned int i;

  csymbols = abfd->tdata.mmo_data->csymbols;
  if (csymbols == NULL && symcount != 0)
    {
      asymbol *c;
      struct mmo_symbol *s;
      struct mmo_symbol **msp;

      /* First we store the symbols into the table we'll return, then we
	 qsort it on the serial number, with secondary on the address of
	 the symbol, to preserve order if there would be non-unique serial
	 numbers.  */
      for (s = abfd->tdata.mmo_data->symbols,
	     msp = (struct mmo_symbol **) alocation;
	   s != NULL;
	   s = s->next, ++msp)
	*msp = s;

      *msp = NULL;

      qsort (alocation, symcount, sizeof (struct mmo_symbol *),
	     mmo_sort_mmo_symbols);

      csymbols = (asymbol *) bfd_alloc (abfd, symcount * sizeof (asymbol));
      if (csymbols == NULL)
	return -1;
      abfd->tdata.mmo_data->csymbols = csymbols;

      for (msp = (struct mmo_symbol **) alocation, c = csymbols;
	   *msp != NULL;
	   msp++, ++c)
	{
	  s = *msp;
	  c->the_bfd = abfd;
	  c->name = s->name;
	  c->value = s->value;
	  c->flags = BSF_GLOBAL;

	  if (s->sym_type == mmo_data_sym)
	    {
	      c->section
		= bfd_get_section_by_name (abfd, MMO_DATA_SECTION_NAME);

	      if (c->section == NULL)
		c->section = bfd_abs_section_ptr;
	      else
		c->value -= c->section->vma;
	    }
	  else if (s->sym_type == mmo_undef_sym)
	    c->section = bfd_und_section_ptr;
	  else if (s->sym_type == mmo_reg_sym)
	    {
	      c->section
		= bfd_make_section_old_way (abfd, MMIX_REG_SECTION_NAME);
	      c->section->flags |= SEC_LINKER_CREATED;
	    }
	  else
	    {
	      asection *textsec
		= bfd_get_section_by_name (abfd, MMO_TEXT_SECTION_NAME);
	      asection *datasec;

	      if (textsec != NULL
		  && c->value >= textsec->vma
		  && c->value <= textsec->vma + textsec->size)
		{
		  c->section = textsec;
		  c->value -= c->section->vma;
		}
	      /* In mmo, symbol types depend on the VMA.  Therefore, if
		 the data section isn't within the usual bounds, its
		 symbols are marked as absolute.  Correct that.  This
		 means we can't have absolute symbols with values matching
		 data section addresses, but we also can't have with
		 absolute symbols with values matching text section
		 addresses.  For such needs, use the ELF format.  */
	      else if ((datasec
			= bfd_get_section_by_name (abfd,
						   MMO_DATA_SECTION_NAME))
		       != NULL
		       && c->value >= datasec->vma
		       && c->value <= datasec->vma + datasec->size)
		{
		  c->section = datasec;
		  c->value -= c->section->vma;
		}
	      else
		c->section = bfd_abs_section_ptr;
	    }

	  c->udata.p = NULL;
	}
    }

  /* Last, overwrite the incoming table with the right-type entries.  */
  for (i = 0; i < symcount; i++)
    *alocation++ = csymbols++;
  *alocation = NULL;

  return symcount;
}

/* Get information about a symbol.  */

static void
mmo_get_symbol_info (bfd *ignore_abfd ATTRIBUTE_UNUSED,
		     asymbol *symbol, symbol_info *ret)
{
  bfd_symbol_info (symbol, ret);
}

static void
mmo_print_symbol (bfd *abfd, void *afile, asymbol *symbol,
		  bfd_print_symbol_type how)
{
  FILE *file = (FILE *) afile;

  switch (how)
    {
    case bfd_print_symbol_name:
      fprintf (file, "%s", symbol->name);
      break;
    default:
      bfd_print_symbol_vandf (abfd, file, symbol);

      fprintf (file, " %-5s %s",
	       symbol->section->name,
	       symbol->name);
    }
}

/* We can't map a file directly into executable code, so the
   size of header information is irrelevant.  */

static int
mmo_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED,
		    struct bfd_link_info *info ATTRIBUTE_UNUSED)
{
  return 0;
}

/* Write the (section-neutral) file preamble.  */

static bool
mmo_internal_write_header (bfd *abfd)
{
  const char lop_pre_bfd[] = { LOP, LOP_PRE, 1, 1};

  if (bfd_write (lop_pre_bfd, 4, abfd) != 4)
    return false;

  /* Copy creation time of original file.  */
  if (bfd_write (abfd->tdata.mmo_data->created, 4, abfd) != 4)
    return false;

  return true;
}

/* Write the LOP_POST record, with global register initializations.
   Z is the Z field of the LOP_POST, corresponding to 255 - number of
   registers at DATA.  The Z = 255 field is filled in with the
   start-address.  */

static bool
mmo_internal_write_post (bfd *abfd, int z, asection *sec)
{
  int i;
  bfd_byte buf[8];
  mmo_write_tetra_raw (abfd, (LOP << 24) | (LOP_POST << 16) | z);

  for (i = z; i < 255; i++)
    {
      bfd_byte *data = mmo_get_loc (sec, i * 8, 8);

      if (bfd_write (data, 8, abfd) != 8)
	return false;
    }

  /* For Z == $255, we always emit the start location; supposedly Main,
     but we have it handy at bfd_get_start_address.  If we're called with
     Z == 255, don't assume DATA is valid.  */
  bfd_put_64 (abfd, bfd_get_start_address (abfd), buf);

  return ! abfd->tdata.mmo_data->have_error && bfd_write (buf, 8, abfd) == 8;
}

/* Translate to and from BFD flags.  This is to make sure that we don't
   get bitten by BFD flag number changes.  */

static flagword
mmo_sec_flags_from_bfd_flags (flagword flags)
{
  flagword oflags = 0;

  if (flags & SEC_ALLOC)
    oflags |= MMO_SEC_ALLOC;
  if (flags & SEC_LOAD)
    oflags |= MMO_SEC_LOAD;
  if (flags & SEC_RELOC)
    oflags |= MMO_SEC_RELOC;
  if (flags & SEC_READONLY)
    oflags |= MMO_SEC_READONLY;
  if (flags & SEC_CODE)
    oflags |= MMO_SEC_CODE;
  if (flags & SEC_DATA)
    oflags |= MMO_SEC_DATA;
  if (flags & SEC_NEVER_LOAD)
    oflags |= MMO_SEC_NEVER_LOAD;
  if (flags & SEC_IS_COMMON)
    oflags |= MMO_SEC_IS_COMMON;
  if (flags & SEC_DEBUGGING)
    oflags |= MMO_SEC_DEBUGGING;

  return oflags;
}

static flagword
bfd_sec_flags_from_mmo_flags (flagword flags)
{
  flagword oflags = 0;

  if (flags & MMO_SEC_ALLOC)
    oflags |= SEC_ALLOC;
  if (flags & MMO_SEC_LOAD)
    oflags |= SEC_LOAD;
  if (flags & MMO_SEC_RELOC)
    oflags |= SEC_RELOC;
  if (flags & MMO_SEC_READONLY)
    oflags |= SEC_READONLY;
  if (flags & MMO_SEC_CODE)
    oflags |= SEC_CODE;
  if (flags & MMO_SEC_DATA)
    oflags |= SEC_DATA;
  if (flags & MMO_SEC_NEVER_LOAD)
    oflags |= SEC_NEVER_LOAD;
  if (flags & MMO_SEC_IS_COMMON)
    oflags |= SEC_IS_COMMON;
  if (flags & MMO_SEC_DEBUGGING)
    oflags |= SEC_DEBUGGING;

  return oflags;
}

/* Return TRUE iff the leading or trailing tetrabyte in SEC is defined and
   is 0.  */

static bool
mmo_has_leading_or_trailing_zero_tetra_p (bfd *abfd, asection *sec)
{
  bfd_vma secaddr = bfd_section_vma (sec);

  if (sec->size < 4)
    return false;

  if (bfd_get_32 (abfd, mmo_get_loc (sec, secaddr, 4)) == 0
      && bfd_get_32 (abfd,
		     mmo_get_loc (sec, secaddr + sec->size - 4, 4)) == 0)
    return true;

  return false;
}

/* Write a section.  */

static bool
mmo_internal_write_section (bfd *abfd, asection *sec)
{
  /* We do it differently depending on what section this is:

   ".text": Output, prepended by information about the first source file
   (not yet implemented.)

   ".data": Output.

   (".MMIX.reg_contents": Not handled here.)

   Anything else: Output inside a lop_spec 80, in the format described
   above.  */

  if (strcmp (sec->name, MMO_TEXT_SECTION_NAME) == 0)
    {
      bfd_vma secaddr = bfd_section_vma (sec);

      /* Because leading and trailing zeros are omitted in output, we need to
	 specify the section boundaries so they're correct when the file
	 is read in again.  That's also the case if this section is
	 specified as not within its usual boundaries or alignments.  */
      if (sec->size != 0
	  && (secaddr + sec->size >= (bfd_vma) 1 << 56
	      || (secaddr & 3) != 0
	      || (sec->size & 3) != 0
	      || mmo_has_leading_or_trailing_zero_tetra_p (abfd, sec)))
	{
	  if (!mmo_write_section_description (abfd, sec))
	    return false;
	}

      /* FIXME: Output source file name and line number.  */
      return mmo_write_loc_chunk_list (abfd, mmo_section_data (sec)->head);
    }
  else if (strcmp (sec->name, MMO_DATA_SECTION_NAME) == 0)
    {
      bfd_vma secaddr = bfd_section_vma (sec);

      /* Same goes as for MMO_TEXT_SECTION_NAME above.  */
      if (sec->size != 0
	  && (secaddr < (bfd_vma) 0x20 << 56
	      || secaddr + sec->size >= (bfd_vma) 0x21 << 56
	      || (secaddr & 3) != 0
	      || (sec->size & 3) != 0
	      || mmo_has_leading_or_trailing_zero_tetra_p (abfd, sec)))
	{
	  if (!mmo_write_section_description (abfd, sec))
	    return false;
	}

      return mmo_write_loc_chunk_list (abfd, mmo_section_data (sec)->head);
    }
  else if (strcmp (sec->name, MMIX_REG_CONTENTS_SECTION_NAME) == 0)
    /* Not handled here.  */
    {
      /* This would normally be an abort call since this can't happen, but
	 we don't do that.  */
      bfd_set_error (bfd_error_bad_value);
      return false;
    }
  else if (startswith (sec->name, MMIX_OTHER_SPEC_SECTION_PREFIX))
    {
      int n = atoi (sec->name + strlen (MMIX_OTHER_SPEC_SECTION_PREFIX));

      mmo_write_tetra_raw (abfd, (LOP << 24) | (LOP_SPEC << 16) | n);
      return (! abfd->tdata.mmo_data->have_error
	      && mmo_write_chunk_list (abfd, mmo_section_data (sec)->head));
    }
  /* Ignore sections that are just allocated or empty; we write out
     _contents_ here.  */
  else if ((bfd_section_flags (sec) & SEC_HAS_CONTENTS) != 0
	   && sec->size != 0)
    {
      if (!mmo_write_section_description (abfd, sec))
	return false;

      /* Writing a LOP_LOC ends the LOP_SPEC data, and makes data actually
	 loaded.  */
      if (bfd_section_flags (sec) & SEC_LOAD)
	return (! abfd->tdata.mmo_data->have_error
		&& mmo_write_loc_chunk_list (abfd,
					 mmo_section_data (sec)->head));
      return (! abfd->tdata.mmo_data->have_error
	      && mmo_write_chunk_list (abfd, mmo_section_data (sec)->head));
    }

  /* Some section without contents.  */
  return true;
}

/* Write the description of a section, extended-mmo-style.  */

static bool
mmo_write_section_description (bfd *abfd, asection *sec)
{
  /* Keep the following document-comment formatted the way it is.  */
/*
INODE
mmo section mapping, , Symbol-table, mmo
SUBSECTION
	mmo section mapping

	The implementation in BFD uses special data type 80 (decimal) to
	encapsulate and describe named sections, containing e.g.@: debug
	information.  If needed, any datum in the encapsulation will be
	quoted using lop_quote.  First comes a 32-bit word holding the
	number of 32-bit words containing the zero-terminated zero-padded
	segment name.  After the name there's a 32-bit word holding flags
	describing the section type.  Then comes a 64-bit big-endian word
	with the section length (in bytes), then another with the section
	start address.  Depending on the type of section, the contents
	might follow, zero-padded to 32-bit boundary.  For a loadable
	section (such as data or code), the contents might follow at some
	later point, not necessarily immediately, as a lop_loc with the
	same start address as in the section description, followed by the
	contents.  This in effect forms a descriptor that must be emitted
	before the actual contents.  Sections described this way must not
	overlap.

	For areas that don't have such descriptors, synthetic sections are
	formed by BFD.  Consecutive contents in the two memory areas
	@samp{0x0000@dots{}00} to @samp{0x01ff@dots{}ff} and
	@samp{0x2000@dots{}00} to @samp{0x20ff@dots{}ff} are entered in
	sections named <<.text>> and <<.data>> respectively.  If an area
	is not otherwise described, but would together with a neighboring
	lower area be less than @samp{0x40000000} bytes long, it is joined
	with the lower area and the gap is zero-filled.  For other cases,
	a new section is formed, named <<.MMIX.sec.@var{n}>>.  Here,
	@var{n} is a number, a running count through the mmo file,
	starting at 0.

EXAMPLE
	A loadable section specified as:

| .section secname,"ax"
| TETRA 1,2,3,4,-1,-2009
| BYTE 80

	and linked to address @samp{0x4}, is represented by the sequence:

| 0x98080050 - lop_spec 80
| 0x00000002 - two 32-bit words for the section name
| 0x7365636e - "secn"
| 0x616d6500 - "ame\0"
| 0x00000033 - flags CODE, READONLY, LOAD, ALLOC
| 0x00000000 - high 32 bits of section length
| 0x0000001c - section length is 28 bytes; 6 * 4 + 1 + alignment to 32 bits
| 0x00000000 - high 32 bits of section address
| 0x00000004 - section address is 4
| 0x98010002 - 64 bits with address of following data
| 0x00000000 - high 32 bits of address
| 0x00000004 - low 32 bits: data starts at address 4
| 0x00000001 - 1
| 0x00000002 - 2
| 0x00000003 - 3
| 0x00000004 - 4
| 0xffffffff - -1
| 0xfffff827 - -2009
| 0x50000000 - 80 as a byte, padded with zeros.

	Note that the lop_spec wrapping does not include the section
	contents.  Compare this to a non-loaded section specified as:

| .section thirdsec
| TETRA 200001,100002
| BYTE 38,40

	This, when linked to address @samp{0x200000000000001c}, is
	represented by:

| 0x98080050 - lop_spec 80
| 0x00000002 - two 32-bit words for the section name
| 0x7365636e - "thir"
| 0x616d6500 - "dsec"
| 0x00000010 - flag READONLY
| 0x00000000 - high 32 bits of section length
| 0x0000000c - section length is 12 bytes; 2 * 4 + 2 + alignment to 32 bits
| 0x20000000 - high 32 bits of address
| 0x0000001c - low 32 bits of address 0x200000000000001c
| 0x00030d41 - 200001
| 0x000186a2 - 100002
| 0x26280000 - 38, 40 as bytes, padded with zeros

	For the latter example, the section contents must not be
	loaded in memory, and is therefore specified as part of the
	special data.  The address is usually unimportant but might
	provide information for e.g.@: the DWARF 2 debugging format.  */

  mmo_write_tetra_raw (abfd, LOP_SPEC_SECTION);
  mmo_write_tetra (abfd, (strlen (sec->name) + 3) / 4);
  mmo_write_chunk (abfd, (bfd_byte *) sec->name, strlen (sec->name));
  mmo_flush_chunk (abfd);
  /* FIXME: We can get debug sections (.debug_line & Co.) with a section
     flag still having SEC_RELOC set.  Investigate.  This might be true
     for all alien sections; perhaps mmo.em should clear that flag.  Might
     be related to weak references.  */
  mmo_write_tetra (abfd,
		   mmo_sec_flags_from_bfd_flags (bfd_section_flags (sec)));
  mmo_write_octa (abfd, sec->size);
  mmo_write_octa (abfd, bfd_section_vma (sec));
  return true;
}

/* We save up all data before output.  */

static bool
mmo_set_section_contents (bfd *abfd ATTRIBUTE_UNUSED, sec_ptr sec,
			  const void *location, file_ptr offset,
			  bfd_size_type bytes_to_do)
{
  /* Iterate over diminishing chunk sizes, copying contents.  */
  while (bytes_to_do)
    {
      /* A minor song-and-dance to make sure we're not bitten by the
	 distant possibility of the cast from bfd_vma to int making the
	 chunk zero-sized.  */
      int chunk_size
	= (int) bytes_to_do != 0 ? bytes_to_do : MMO_SEC_CONTENTS_CHUNK_SIZE;
      bfd_byte *loc;

      do
	loc = mmo_get_loc (sec, sec->vma + offset, chunk_size);
      while (loc == NULL && (chunk_size /= 2) != 0);

      if (chunk_size == 0)
	return false;

      memcpy (loc, location, chunk_size);

      location = (bfd_byte *) location + chunk_size;
      bytes_to_do -= chunk_size;
      offset += chunk_size;
    }
  return true;
}

/* Add a symbol to a trie-tree.  */

static bool
mmo_internal_add_3_sym (bfd *abfd, struct mmo_symbol_trie *rootp,
			const struct mmo_symbol *symp)
{
  const char *name = symp->name;
  struct mmo_symbol_trie *trie = rootp;
  struct mmo_symbol_trie **triep = NULL;

  while (*name && trie != NULL)
    {
      if (*name < trie->symchar)
	{
	  triep = &trie->left;
	  trie = trie->left;
	}
      else if (*name > trie->symchar)
	{
	  triep = &trie->right;
	  trie = trie->right;
	}
      else if (*name == trie->symchar)
	{
	  triep = &trie->middle;
	  name++;

	  /* Make sure "trie" points to where we should fill in the
	     current symbol whenever we've iterated through "name".  We
	     would lose the right position if we encounter "foobar" then
	     "foo".  */
	  if (*name)
	    trie = trie->middle;
	}
    }

  while (*name != 0)
    {
      /* Create middle branches for the rest of the characters.  */
      trie = bfd_zalloc (abfd, sizeof (struct mmo_symbol_trie));
      *triep = trie;
      trie->symchar = *name++;
      triep = &trie->middle;
    }

  /* We discover a duplicate symbol rather late in the process, but still;
     we discover it and bail out.  */
  if (trie->sym.name != NULL)
    {
      _bfd_error_handler
	/* xgettext:c-format */
	(_("%pB: invalid symbol table: duplicate symbol `%s'\n"),
	 abfd, trie->sym.name);
      bfd_set_error (bfd_error_bad_value);
      return false;
    }

  memcpy (&trie->sym, symp, sizeof *symp);
  return true;
}

/* Find out the length of the serialized version of a trie in bytes.  */

static unsigned int
mmo_internal_3_length (bfd *abfd, struct mmo_symbol_trie *trie)
{
  /* First, one for the control byte.  */
  unsigned int length = 1;

  if (trie == NULL)
    return 0;

  /* Add in the recursion to the left.  */
  length += mmo_internal_3_length (abfd, trie->left);

  /* Add in the middle trie and the character.  */
  length += 1 + mmo_internal_3_length (abfd, trie->middle);

  /* Add in the recursion to the right.  */
  length += mmo_internal_3_length (abfd, trie->right);

  /* Add in bytes for the symbol (if this is an endnode). */
  if (trie->sym.name != NULL)
    {
      unsigned int serno = trie->sym.serno;

      /* First what it takes to encode the value. */
      if (trie->sym.sym_type == mmo_reg_sym)
	length++;
      else if (trie->sym.sym_type == mmo_undef_sym)
	length += 2;
      else
	{
	  bfd_vma value = trie->sym.value;

	  /* Coded in one to eight following bytes.  */
	  if (trie->sym.sym_type == mmo_data_sym)
	    value -= (bfd_vma) 0x20 << 56;

	  do
	    {
	      value >>= 8;
	      length++;
	    }
	  while (value != 0);
	}

      /* Find out what it takes to encode the serial number.  */
      do
	{
	  serno >>= 7;
	  length++;
	}
      while (serno != 0);
    }

  return length;
}

/* Helper function for outputting the serial number of a symbol, output as
   a variant of leb128 (see dwarf2 documentation) which could be called
   beb128.  Using a helper function and recursion simplifies debugging.  */

static void
mmo_beb128_out (bfd *abfd, int serno, int marker)
{
  if (serno & ~0x7f)
    mmo_beb128_out (abfd, serno >> 7, 0);
  mmo_write_byte (abfd, marker | (serno & 0x7f));
}

/* Serialize a trie.  */

static void
mmo_internal_3_dump (bfd *abfd, struct mmo_symbol_trie *trie)
{
  bfd_byte control = 0;

  if (trie == NULL)
    return;

  if (trie->left)
    control |= MMO3_LEFT;

  if (trie->middle)
    control |= MMO3_MIDDLE;

  if (trie->right)
    control |= MMO3_RIGHT;

  if (trie->sym.name != NULL)
    {
      /* Encode the symbol type and length of value bytes.  */
      if (trie->sym.sym_type == mmo_reg_sym)
	control |= MMO3_REGQUAL_BITS;
      else if (trie->sym.sym_type == mmo_undef_sym)
	control |= MMO3_UNDEF;
      else
	{
	  bfd_vma value = trie->sym.value;

	  /* Coded in 1..8 following bytes.  */
	  if (trie->sym.sym_type == mmo_data_sym)
	    {
	      control |= MMO3_DATA;
	      value -= (bfd_vma) 0x20 << 56;
	    }

	  do
	    {
	      value >>= 8;
	      control++;
	    }
	  while (value != 0);
	}
    }

  /* The control byte is output before recursing.  */
  mmo_write_byte (abfd, control);

  mmo_internal_3_dump (abfd, trie->left);

  if (control & MMO3_SYMBITS)
    {
      mmo_write_byte (abfd, trie->symchar);

      if (trie->sym.name != NULL)
	{
	  if (trie->sym.sym_type == mmo_reg_sym)
	    mmo_write_byte (abfd, trie->sym.value);
	  else if (trie->sym.sym_type == mmo_undef_sym)
	    {
	      mmo_write_byte (abfd, 0);
	      mmo_write_byte (abfd, 0);
	    }
	  else
	    {
	      bfd_vma value = trie->sym.value;

	      bfd_byte byte_n = control & 15;

	      /* Coded in 1..8 following bytes.  Note that the value is
		 shifted out big-endian.  */
	      if (trie->sym.sym_type == mmo_data_sym)
		{
		  value -= (bfd_vma) 0x20 << 56;
		  byte_n -= 8;
		}

	      do
		{
		  mmo_write_byte (abfd, (value >> ((byte_n - 1) * 8)) & 0xff);
		  byte_n--;
		}
	      while (byte_n != 0);
	    }

	  mmo_beb128_out (abfd, trie->sym.serno, 128);
	}
      mmo_internal_3_dump (abfd, trie->middle);
    }
  mmo_internal_3_dump (abfd, trie->right);
}

/* Write symbols in mmo format.  Also write the lop_end terminator.  */

static bool
mmo_write_symbols_and_terminator (bfd *abfd)
{
  int count = bfd_get_symcount (abfd);
  asymbol **table;
  asymbol **orig_table = bfd_get_outsymbols (abfd);
  int serno;
  struct mmo_symbol_trie root;
  int trie_len;
  int i;
  bfd_byte buf[4];

  /* Create a symbol for "Main".  */
  asymbol *fakemain = bfd_make_empty_symbol (abfd);

  fakemain->flags = BSF_GLOBAL;
  fakemain->value = bfd_get_start_address (abfd);
  fakemain->name = MMIX_START_SYMBOL_NAME;
  fakemain->section = bfd_abs_section_ptr;

  memset (&root, 0, sizeof (root));

  /* Make all symbols take a left turn.  */
  root.symchar = 0xff;

  /* There must always be a ":Main", so we'll add one if there are no
     symbols.  Make sure we have room for it.  */
  table = bfd_alloc (abfd, (count + 1) * sizeof (asymbol *));
  if (table == NULL)
    return false;

  if (count != 0)
    memcpy (table, orig_table, count * sizeof (asymbol *));

  /* Move :Main (if there is one) to the first position.  This is
     necessary to get the same layout of the trie-tree when linking as
     when objcopying the result as in the objcopy.exp test "simple objcopy
     of executable".  It also automatically takes care of assigning serial
     number 1 to :Main (as is mandatory).  */
  for (i = 0; i < count; i++)
    if (table[i] != NULL
	&& strcmp (table[i]->name, MMIX_START_SYMBOL_NAME) == 0
	&& (table[i]->flags & (BSF_DEBUGGING|BSF_GLOBAL)) == BSF_GLOBAL)
      {
	asymbol *mainsym = table[i];
	bfd_vma mainvalue
	  = (mainsym->value
	     + mainsym->section->output_section->vma
	     + mainsym->section->output_offset);
	memcpy (table + 1, orig_table, i * sizeof (asymbol *));
	table[0] = mainsym;

	/* Check that the value assigned to :Main is the same as the entry
	   address.  The default linker script asserts this.  This is as
	   good a place as any to check this consistency. */
	if (mainvalue != bfd_get_start_address (abfd)
	    && !mmo_ignore_symbol_consistency (abfd))
	  {
	    /* Arbitrary buffer to hold the printable representation of a
	       vma.  */
	    bfd_vma vma_start = bfd_get_start_address (abfd);

	    _bfd_error_handler
	      /* xgettext:c-format */
	      (_("%pB: bad symbol definition: `Main' set to %" PRIx64 " rather"
		 " than the start address %" PRIx64 "\n"),
	       abfd, mainvalue, vma_start);
	    bfd_set_error (bfd_error_bad_value);
	    return false;
	  }
	break;
      }
  if (i == count && count != 0)
    {
      /* When there are symbols, there must be a :Main.  There was no
	 :Main, so we need to add it manually.  */
      memcpy (table + 1, orig_table, count * sizeof (asymbol *));
      table[0] = fakemain;
      count++;
    }

  /* Don't bother inspecting symbols in plugin dummy objects; their
     symbols aren't fully inspectable.  */
  if ((abfd->flags & BFD_PLUGIN) == 0)
    {
      for (i = 0, serno = 1; i < count && table[i] != NULL; i++)
	{
	  asymbol *s = table[i];

	  /* It's not enough to consult bfd_is_local_label, since it does not
	     mean "local" in the sense of linkable-and-observable-after-link.
	     Let's just check the BSF_GLOBAL flag.

	     Also, don't export symbols with characters not in the
	     allowed set.  */
	  if ((s->flags & (BSF_DEBUGGING|BSF_GLOBAL)) == BSF_GLOBAL
	      && strspn (s->name,
			 valid_mmo_symbol_character_set) == strlen (s->name))
	    {
	      struct mmo_symbol sym;
	      memset (&sym, 0, sizeof (sym));

	      /* Need to strip const here; strdup:ing would leak and the
		 existing string must be safe to reuse.  */
	      sym.name = (char *) s->name;
	      sym.value =
		s->value
		+ s->section->output_section->vma
		+ s->section->output_offset;

	      if (bfd_is_und_section (s->section))
		sym.sym_type = mmo_undef_sym;
	      else if (strcmp (s->section->name, MMO_DATA_SECTION_NAME) == 0
		       /* The encoding of data symbols require that the "rest"
			  of the value fits in 6 bytes, so the upper two bytes
			  must be 0x2000.  All other symbols get to be the
			  absolute type.  */
		       && (sym.value >> 48) == 0x2000)
		sym.sym_type = mmo_data_sym;
	      else if (strcmp (s->section->name, MMIX_REG_SECTION_NAME) == 0)
		sym.sym_type = mmo_reg_sym;
	      else if (strcmp (s->section->name,
			       MMIX_REG_CONTENTS_SECTION_NAME) == 0)
		{
		  sym.sym_type = mmo_reg_sym;
		  sym.value /= 8;
		}
	      else
		sym.sym_type = mmo_abs_sym;

	      /* FIXME: We assume the order of the received symbols is an
		 ordered mapping of the serial numbers.  This is not
		 necessarily true if we e.g. objcopy a mmo file to another and
		 there are gaps in the numbering.  Not sure if this can
		 happen.  Not sure what to do.  */
	      sym.serno = serno++;

	      if (! mmo_internal_add_3_sym (abfd, &root, &sym))
		return false;
	    }
	}
    }

  /* Change the root node to be a ":"-prefix.  */
  root.symchar = ':';
  root.middle = root.left;
  root.right = NULL;
  root.left = NULL;

  /* We have to find out if we can fit the whole symbol table in the mmo
     symtab.  It would be bad to assume we can always fit it in 262144
     bytes.  If we can't, just leave the Main symbol.  */
  trie_len = (mmo_internal_3_length (abfd, &root) + 3)/4;

  if (trie_len > 0xffff)
    {
      /* Test this code by using a lower limit in the test above and check
	 that the single "Main" symbol is emitted and handled properly.
	 There's no specific test-case.  */
      struct mmo_symbol sym;

      _bfd_error_handler
	/* xgettext:c-format */
	(_("%pB: warning: symbol table too large for mmo, larger than 65535"
	   " 32-bit words: %d.  Only `Main' will be emitted.\n"),
	 abfd, trie_len);

      memset (&sym, 0, sizeof (sym));
      sym.sym_type = mmo_abs_sym;
      sym.name = MMIX_START_SYMBOL_NAME;
      sym.serno = 1;
      sym.value = bfd_get_start_address (abfd);

      /* Then patch up a symbol table to be just the ":Main" symbol.  */
      memset (&root, 0, sizeof (root));
      root.left = root.middle;
      root.symchar = 0xff;
      root.middle = NULL;
      root.right = NULL;

      if (! mmo_internal_add_3_sym (abfd, &root, &sym))
	return false;

      root.symchar = ':';
      root.middle = root.left;
      root.right = NULL;
      root.left = NULL;

      trie_len = (mmo_internal_3_length (abfd, &root) + 3)/4;
    }

  /* Reset the written-bytes counter.  */
  abfd->tdata.mmo_data->byte_no = 0;

  /* Put out the lop_stab mark.  */
  bfd_put_32 (abfd, (LOP << 24) | (LOP_STAB << 16), buf);
  if (bfd_write (buf, 4, abfd) != 4)
    return false;

  /* Dump out symbols.  */
  mmo_internal_3_dump (abfd, &root);

  if (trie_len != (abfd->tdata.mmo_data->byte_no + 3)/4)
    {
      /* I haven't seen this trig.  It seems no use claiming this case
	 isn't debugged and abort if we get here.  Instead emit a
	 diagnostic and fail "normally".  */
      _bfd_error_handler
	/* xgettext:c-format */
	(_("%pB: internal error, symbol table changed size from %d to %d"
	   " words\n"),
	 abfd, trie_len,
	 (abfd->tdata.mmo_data->byte_no + 3)/4);
      bfd_set_error (bfd_error_bad_value);
      return false;
    }

  /* Dump out remaining bytes in the buffer and handle I/O errors by
     propagating errors.  */
  if ((abfd->tdata.mmo_data->byte_no % 4) != 0
      || abfd->tdata.mmo_data->have_error)
    {
      memset (abfd->tdata.mmo_data->buf + (abfd->tdata.mmo_data->byte_no % 4),
	      0, 4 - (abfd->tdata.mmo_data->byte_no % 4));

      if (abfd->tdata.mmo_data->have_error
	  || bfd_write (abfd->tdata.mmo_data->buf, 4, abfd) != 4)
	return false;
    }

  bfd_put_32 (abfd, (LOP << 24) | (LOP_END << 16) | trie_len, buf);
  return bfd_write (buf, 4, abfd) == 4;
}

/* Write section unless it is the register contents section.  For that, we
   instead store the section in the supplied pointer.  This function is
   used through bfd_map_over_sections.  */

static void
mmo_write_section_unless_reg_contents (bfd *abfd, asection *sec, void *p)
{
  struct mmo_write_sec_info *infop = (struct mmo_write_sec_info *) p;

  if (! infop->retval)
    return;

  if (strcmp (sec->name, MMIX_REG_CONTENTS_SECTION_NAME) == 0)
    {
      infop->reg_section = sec;
      return;
    }

  /* Exclude the convenience register section.  */
  if (strcmp (sec->name, MMIX_REG_SECTION_NAME) == 0)
    {
      if (bfd_section_flags (sec) & SEC_HAS_CONTENTS)
	{
	  /* Make sure it hasn't got contents.  It seems impossible to
	     make it carry contents, so we don't have a test-case for
	     this.  */
	  _bfd_error_handler
	    /* xgettext:c-format */
	    (_("%pB: internal error, internal register section %pA had"
	       " contents\n"),
	     abfd, sec);
	  bfd_set_error (bfd_error_bad_value);
	  infop->retval = false;
	  return;
	}

      return;
    }

  infop->retval = mmo_internal_write_section (abfd, sec);
}

/* Do the actual output of a file.  Assumes mmo_set_section_contents is
   already called. */

static bool
mmo_write_object_contents (bfd *abfd)
{
  struct mmo_write_sec_info wsecinfo;

  /* First, there are a few words of preamble.  */
  if (! mmo_internal_write_header (abfd))
    return false;

  wsecinfo.reg_section = NULL;
  wsecinfo.retval = true;

  bfd_map_over_sections (abfd, mmo_write_section_unless_reg_contents,
			 &wsecinfo);

  if (! wsecinfo.retval)
    return false;

  if (wsecinfo.reg_section != NULL)
    {
      asection *sec = wsecinfo.reg_section;
      unsigned int z = (unsigned int) (sec->vma / 8);

      /* Registers 0..31 must not be global.  Do sanity check on the "vma"
	 of the register contents section and check that it corresponds to
	 the length of the section.  */
      if (z < 32 || z >= 255 || (sec->vma & 7) != 0
	  || sec->vma != 256 * 8 - sec->size - 8)
	{
	  bfd_set_error (bfd_error_bad_value);

	  if (sec->size == 0)
	    /* There must always be at least one such register.  */
	    _bfd_error_handler
	      (_("%pB: no initialized registers; section length 0\n"),
	       abfd);
	  else if (sec->vma > (256 - 32) * 8)
	    /* Provide better error message for the case of too many
	       global registers.  */
	    _bfd_error_handler
	      /* xgettext:c-format */
	      (_("%pB: too many initialized registers; section length %" PRId64),
	       abfd, (int64_t) sec->size);
	  else
	    _bfd_error_handler
	      /* xgettext:c-format */
	      (_("%pB: invalid start address for initialized registers of"
		 " length %" PRId64 ": %#" PRIx64),
	       abfd, (int64_t) sec->size, (uint64_t) sec->vma);

	  return false;
	}

      if (! mmo_internal_write_post (abfd, z, sec))
	return false;
    }
  else
    if (! mmo_internal_write_post (abfd, 255, NULL))
      return false;

  return mmo_write_symbols_and_terminator (abfd);
}

/* If there's anything in particular in a mmo bfd that we want to free,
   make this a real function.  Only do this if you see major memory
   thrashing; zealous free:ing will cause unwanted behavior, especially if
   you "free" memory allocated with "bfd_alloc", or even "bfd_release" a
   block allocated with "bfd_alloc"; they're really allocated from an
   obstack, and we don't know what was allocated there since this
   particular allocation.  */

#define	mmo_close_and_cleanup _bfd_generic_close_and_cleanup
#define mmo_bfd_free_cached_info _bfd_generic_bfd_free_cached_info

/* Perhaps we need to adjust this one; mmo labels (originally) without a
   leading ':' might more appropriately be called local.  */
#define mmo_bfd_is_local_label_name bfd_generic_is_local_label_name
#define mmo_bfd_is_target_special_symbol _bfd_bool_bfd_asymbol_false

#define mmo_get_symbol_version_string \
  _bfd_nosymbols_get_symbol_version_string

/* Is this one really used or defined by anyone?  */
#define mmo_get_lineno _bfd_nosymbols_get_lineno

/* FIXME: We can do better on this one, if we have a dwarf2 .debug_line
   section or if MMO line numbers are implemented.  */
#define mmo_find_nearest_line _bfd_nosymbols_find_nearest_line
#define mmo_find_nearest_line_with_alt _bfd_nosymbols_find_nearest_line_with_alt
#define mmo_find_line _bfd_nosymbols_find_line
#define mmo_find_inliner_info _bfd_nosymbols_find_inliner_info
#define mmo_make_empty_symbol _bfd_generic_make_empty_symbol
#define mmo_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
#define mmo_read_minisymbols _bfd_generic_read_minisymbols
#define mmo_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol

#define mmo_get_section_contents_in_window \
  _bfd_generic_get_section_contents_in_window
#define mmo_bfd_get_relocated_section_contents \
  bfd_generic_get_relocated_section_contents
#define mmo_bfd_gc_sections bfd_generic_gc_sections
#define mmo_bfd_lookup_section_flags bfd_generic_lookup_section_flags
#define mmo_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
#define mmo_bfd_link_add_symbols _bfd_generic_link_add_symbols
#define mmo_bfd_link_just_syms _bfd_generic_link_just_syms
#define mmo_bfd_copy_link_hash_symbol_type \
  _bfd_generic_copy_link_hash_symbol_type
#define mmo_bfd_final_link _bfd_generic_final_link
#define mmo_bfd_link_split_section _bfd_generic_link_split_section
#define mmo_bfd_link_check_relocs  _bfd_generic_link_check_relocs

/* Strictly speaking, only MMIX uses this restricted format, but let's not
   stop anybody from shooting themselves in the foot.  */
#define mmo_set_arch_mach bfd_default_set_arch_mach
#define mmo_bfd_relax_section bfd_generic_relax_section
#define mmo_bfd_merge_sections bfd_generic_merge_sections
#define mmo_bfd_is_group_section bfd_generic_is_group_section
#define mmo_bfd_group_name bfd_generic_group_name
#define mmo_bfd_discard_group bfd_generic_discard_group
#define mmo_section_already_linked \
  _bfd_generic_section_already_linked
#define mmo_bfd_define_common_symbol bfd_generic_define_common_symbol
#define mmo_bfd_link_hide_symbol _bfd_generic_link_hide_symbol
#define mmo_bfd_define_start_stop bfd_generic_define_start_stop

/* We want to copy time of creation, otherwise we'd use
   BFD_JUMP_TABLE_COPY (_bfd_generic).  */
#define mmo_bfd_merge_private_bfd_data _bfd_generic_bfd_merge_private_bfd_data
#define mmo_bfd_copy_private_section_data _bfd_generic_bfd_copy_private_section_data
#define mmo_bfd_copy_private_symbol_data _bfd_generic_bfd_copy_private_symbol_data
#define mmo_bfd_copy_private_header_data _bfd_generic_bfd_copy_private_header_data
#define mmo_bfd_set_private_flags _bfd_generic_bfd_set_private_flags
#define mmo_bfd_print_private_bfd_data _bfd_generic_bfd_print_private_bfd_data

const bfd_target mmix_mmo_vec =
{
  "mmo",			/* name */
  bfd_target_mmo_flavour,
  BFD_ENDIAN_BIG,		/* target byte order */
  BFD_ENDIAN_BIG,		/* target headers byte order */

  /* FIXME: Might need adjustments.  */
  (HAS_RELOC | EXEC_P |		/* object flags */
   HAS_LINENO | HAS_DEBUG |
   HAS_SYMS | HAS_LOCALS | WP_TEXT),

  /* FIXME: Might need adjustments.  */
  (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD
   | SEC_READONLY | SEC_EXCLUDE | SEC_DEBUGGING | SEC_IN_MEMORY),
				/* section flags */
  0,				/* leading underscore */
  ' ',				/* ar_pad_char */
  16,				/* ar_max_namelen */
  0,				/* match priority.  */
  TARGET_KEEP_UNUSED_SECTION_SYMBOLS, /* keep unused section symbols.  */
  bfd_getb64, bfd_getb_signed_64, bfd_putb64,
  bfd_getb32, bfd_getb_signed_32, bfd_putb32,
  bfd_getb16, bfd_getb_signed_16, bfd_putb16,	/* data */
  bfd_getb64, bfd_getb_signed_64, bfd_putb64,
  bfd_getb32, bfd_getb_signed_32, bfd_putb32,
  bfd_getb16, bfd_getb_signed_16, bfd_putb16,	/* hdrs */

  {
    _bfd_dummy_target,
    mmo_object_p,		/* bfd_check_format */
    _bfd_dummy_target,
    _bfd_dummy_target,
  },
  {
    _bfd_bool_bfd_false_error,
    mmo_mkobject,
    _bfd_bool_bfd_false_error,
    _bfd_bool_bfd_false_error,
  },
  {				/* bfd_write_contents */
    _bfd_bool_bfd_false_error,
    mmo_write_object_contents,
    _bfd_bool_bfd_false_error,
    _bfd_bool_bfd_false_error,
  },

  BFD_JUMP_TABLE_GENERIC (mmo),
  BFD_JUMP_TABLE_COPY (mmo),
  BFD_JUMP_TABLE_CORE (_bfd_nocore),
  BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
  BFD_JUMP_TABLE_SYMBOLS (mmo),
  BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
  BFD_JUMP_TABLE_WRITE (mmo),
  BFD_JUMP_TABLE_LINK (mmo),
  BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),

  NULL,

  NULL
};