summaryrefslogtreecommitdiff
path: root/DuetPkg/BootSector/start64.asm
blob: 5491722e58cea637701cd4d86c0505ec0c4eaeff (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
;------------------------------------------------------------------------------
;*
;*   Copyright 2006 - 2007, Intel Corporation                                                         
;*   All rights reserved. This program and the accompanying materials                          
;*   are licensed and made available under the terms and conditions of the BSD License         
;*   which accompanies this distribution.  The full text of the license may be found at        
;*   http://opensource.org/licenses/bsd-license.php                                            
;*                                                                                             
;*   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
;*   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             
;*   
;*    start64.asm
;*  
;*   Abstract:
;*
;------------------------------------------------------------------------------

        .model  small
        .stack
        .486p
        .code

FAT_DIRECTORY_ENTRY_SIZE    EQU     020h
FAT_DIRECTORY_ENTRY_SHIFT   EQU     5
BLOCK_SIZE                  EQU     0200h
BLOCK_MASK                  EQU     01ffh
BLOCK_SHIFT                 EQU     9

        org 0h
Ia32Jump:
  jmp   BootSectorEntryPoint  ; JMP inst    - 3 bytes
  nop

OemId             db  "INTEL   "    ; OemId               - 8 bytes

SectorSize        dw  0             ; Sector Size         - 16 bits
SectorsPerCluster db  0             ; Sector Per Cluster  - 8 bits
ReservedSectors   dw  0             ; Reserved Sectors    - 16 bits
NoFats            db  0             ; Number of FATs      - 8 bits
RootEntries       dw  0             ; Root Entries        - 16 bits
Sectors           dw  0             ; Number of Sectors   - 16 bits
Media             db  0             ; Media               - 8 bits  - ignored
SectorsPerFat     dw  0             ; Sectors Per FAT     - 16 bits
SectorsPerTrack   dw  0             ; Sectors Per Track   - 16 bits - ignored
Heads             dw  0             ; Heads               - 16 bits - ignored
HiddenSectors     dd  0             ; Hidden Sectors      - 32 bits - ignored
LargeSectors      dd  0             ; Large Sectors       - 32 bits 
PhysicalDrive     db  0             ; PhysicalDriveNumber - 8 bits  - ignored
CurrentHead       db  0             ; Current Head        - 8 bits
Signature         db  0             ; Signature           - 8 bits  - ignored
VolId             db  "    "        ; Volume Serial Number- 4 bytes
FatLabel          db  "           " ; Label               - 11 bytes
SystemId          db  "FAT12   "    ; SystemId            - 8 bytes

BootSectorEntryPoint:
        ASSUME  ds:@code
        ASSUME  ss:@code
      ; ds = 1000, es = 2000 + x (size of first cluster >> 4)
      ; cx = Start Cluster of EfiLdr
      ; dx = Start Cluster of Efivar.bin

; Re use the BPB data stored in Boot Sector
        mov     bp,07c00h

        push    cx
; Read Efivar.bin
;       1000:dx    = DirectoryEntry of Efivar.bin -> BS.com has filled already
        mov     ax,01900h
        mov     es,ax
        test    dx,dx
        jnz     CheckVarStoreSize

        mov     al,1
NoVarStore:
        push    es
; Set the 5th byte start @ 0:19000 to non-zero indicating we should init var store header in DxeIpl
        mov     byte ptr es:[4],al
        jmp     SaveVolumeId

CheckVarStoreSize:
        mov     di,dx
        cmp     dword ptr ds:[di+2], 04000h
        mov     al,2
        jne     NoVarStore

LoadVarStore:
        mov     al,0
        mov     byte ptr es:[4],al
        mov     cx,word ptr[di]
;       ES:DI = 1500:0
        xor     di,di
        push    es
        mov     ax,01500h
        mov     es,ax
        call    ReadFile
SaveVolumeId:
        pop     es
        mov     ax,word ptr [bp+VolId]
        mov     word ptr es:[0],ax                  ; Save Volume Id to 0:19000. we will find the correct volume according to this VolumeId
        mov     ax,word ptr [bp+VolId+2]
        mov     word ptr es:[2],ax

; Read Efildr
        pop     cx
;       cx    = Start Cluster of Efildr -> BS.com has filled already
;       ES:DI = 2000:0, first cluster will be read again
        xor     di,di                               ; di = 0
        mov     ax,02000h
        mov     es,ax
        call    ReadFile
        mov     ax,cs
        mov     word ptr cs:[JumpSegment],ax

CheckEm64T:
        mov  eax, 080000001h
;        cpuid
        dw   0A20Fh
        bt   edx, 29
        jc   CheckEm64TPass
        push cs
        pop  ds
        lea  si, [Em64String]
        mov  cx, 18
        jmp  PrintStringAndHalt
CheckEm64TPass:
JumpFarInstruction:
        db      0eah
JumpOffset:
        dw      0200h
JumpSegment:
        dw      2000h



; ****************************************************************************
; ReadFile
;
; Arguments:
;   CX    = Start Cluster of File
;   ES:DI = Buffer to store file content read from disk
;
; Return:
;   (ES << 4 + DI) = end of file content Buffer
;
; ****************************************************************************
ReadFile:
; si      = NumberOfClusters
; cx      = ClusterNumber
; dx      = CachedFatSectorNumber
; ds:0000 = CacheFatSectorBuffer
; es:di   = Buffer to load file
; bx      = NextClusterNumber
        pusha
        mov     si,1                                ; NumberOfClusters = 1
        push    cx                                  ; Push Start Cluster onto stack
        mov     dx,0fffh                            ; CachedFatSectorNumber = 0xfff
FatChainLoop:
        mov     ax,cx                               ; ax = ClusterNumber    
        and     ax,0ff8h                            ; ax = ax & 0xff8
        cmp     ax,0ff8h                            ; See if this is the last cluster
        je      FoundLastCluster                    ; Jump if last cluster found
        mov     ax,cx                               ; ax = ClusterNumber
        shl     ax,1                                ; ax = ClusterNumber * 2
        add     ax,cx                               ; ax = ClusterNumber * 2 + ClusterNumber = ClusterNumber * 3
        shr     ax,1                                ; FatOffset = ClusterNumber*3 / 2
        push    si                                  ; Save si
        mov     si,ax                               ; si = FatOffset
        shr     ax,BLOCK_SHIFT                      ; ax = FatOffset >> BLOCK_SHIFT
        add     ax,word ptr [bp+ReservedSectors]    ; ax = FatSectorNumber = ReservedSectors + (FatOffset >> BLOCK_OFFSET)
        and     si,BLOCK_MASK                       ; si = FatOffset & BLOCK_MASK
        cmp     ax,dx                               ; Compare FatSectorNumber to CachedFatSectorNumber
        je      SkipFatRead
        mov     bx,2                                
        push    es
        push    ds
        pop     es
        call    ReadBlocks                          ; Read 2 blocks starting at AX storing at ES:DI
        pop     es
        mov     dx,ax                               ; CachedFatSectorNumber = FatSectorNumber
SkipFatRead:
        mov     bx,word ptr [si]                    ; bx = NextClusterNumber
        mov     ax,cx                               ; ax = ClusterNumber
        and     ax,1                                ; See if this is an odd cluster number
        je      EvenFatEntry
        shr     bx,4                                ; NextClusterNumber = NextClusterNumber >> 4
EvenFatEntry:
        and     bx,0fffh                            ; Strip upper 4 bits of NextClusterNumber
        pop     si                                  ; Restore si
        dec     bx                                  ; bx = NextClusterNumber - 1
        cmp     bx,cx                               ; See if (NextClusterNumber-1)==ClusterNumber
        jne     ReadClusters
        inc     bx                                  ; bx = NextClusterNumber
        inc     si                                  ; NumberOfClusters++
        mov     cx,bx                               ; ClusterNumber = NextClusterNumber
        jmp     FatChainLoop
ReadClusters:
        inc     bx
        pop     ax                                  ; ax = StartCluster
        push    bx                                  ; StartCluster = NextClusterNumber
        mov     cx,bx                               ; ClusterNumber = NextClusterNumber
        sub     ax,2                                ; ax = StartCluster - 2
        xor     bh,bh                               
        mov     bl,byte ptr [bp+SectorsPerCluster]  ; bx = SectorsPerCluster
        mul     bx                                  ; ax = (StartCluster - 2) * SectorsPerCluster
        add     ax, word ptr [bp]                   ; ax = FirstClusterLBA + (StartCluster-2)*SectorsPerCluster
        push    ax                                  ; save start sector
        mov     ax,si                               ; ax = NumberOfClusters
        mul     bx                                  ; ax = NumberOfClusters * SectorsPerCluster
        mov     bx,ax                               ; bx = Number of Sectors
        pop     ax                                  ; ax = Start Sector
        call    ReadBlocks
        mov     si,1                                ; NumberOfClusters = 1
        jmp     FatChainLoop
FoundLastCluster:
        pop     cx
        popa
        ret


; ****************************************************************************
; ReadBlocks - Reads a set of blocks from a block device
;
; AX    = Start LBA
; BX    = Number of Blocks to Read
; ES:DI = Buffer to store sectors read from disk
; ****************************************************************************

; cx = Blocks
; bx = NumberOfBlocks
; si = StartLBA

ReadBlocks:
        pusha
        add     eax,dword ptr [bp+LBAOffsetForBootSector]    ; Add LBAOffsetForBootSector to Start LBA
        add     eax,dword ptr [bp+HiddenSectors]    ; Add HiddenSectors to Start LBA
        mov     esi,eax                             ; esi = Start LBA
        mov     cx,bx                               ; cx = Number of blocks to read
ReadCylinderLoop:
        mov     bp,07bfch                           ; bp = 0x7bfc
        mov     eax,esi                             ; eax = Start LBA
        xor     edx,edx                             ; edx = 0
        movzx   ebx,word ptr [bp]                   ; bx = MaxSector
        div     ebx                                 ; ax = StartLBA / MaxSector
        inc     dx                                  ; dx = (StartLBA % MaxSector) + 1

        mov     bx,word ptr [bp]                    ; bx = MaxSector
        sub     bx,dx                               ; bx = MaxSector - Sector
        inc     bx                                  ; bx = MaxSector - Sector + 1
        cmp     cx,bx                               ; Compare (Blocks) to (MaxSector - Sector + 1)
        jg      LimitTransfer
        mov     bx,cx                               ; bx = Blocks
LimitTransfer:
        push    ax                                  ; save ax
        mov     ax,es                               ; ax = es
        shr     ax,(BLOCK_SHIFT-4)                  ; ax = Number of blocks into mem system
        and     ax,07fh                             ; ax = Number of blocks into current seg
        add     ax,bx                               ; ax = End Block number of transfer
        cmp     ax,080h                             ; See if it crosses a 64K boundry
        jle     NotCrossing64KBoundry               ; Branch if not crossing 64K boundry
        sub     ax,080h                             ; ax = Number of blocks past 64K boundry
        sub     bx,ax                               ; Decrease transfer size by block overage
NotCrossing64KBoundry:
        pop     ax                                  ; restore ax

        push    cx
        mov     cl,dl                               ; cl = (StartLBA % MaxSector) + 1 = Sector
        xor     dx,dx                               ; dx = 0
        div     word ptr [bp+2]                     ; ax = ax / (MaxHead + 1) = Cylinder  
                                                    ; dx = ax % (MaxHead + 1) = Head

        push    bx                                  ; Save number of blocks to transfer
        mov     dh,dl                               ; dh = Head
        mov     bp,07c00h                           ; bp = 0x7c00
        mov     dl,byte ptr [bp+PhysicalDrive]      ; dl = Drive Number
        mov     ch,al                               ; ch = Cylinder
        mov     al,bl                               ; al = Blocks
        mov     ah,2                                ; ah = Function 2
        mov     bx,di                               ; es:bx = Buffer address
        int     013h
        jc      DiskError
        pop     bx
        pop     cx
        movzx   ebx,bx
        add     esi,ebx                             ; StartLBA = StartLBA + NumberOfBlocks
        sub     cx,bx                               ; Blocks = Blocks - NumberOfBlocks
        mov     ax,es
        shl     bx,(BLOCK_SHIFT-4)
        add     ax,bx
        mov     es,ax                               ; es:di = es:di + NumberOfBlocks*BLOCK_SIZE
        cmp     cx,0
        jne     ReadCylinderLoop
        popa
        ret

DiskError:
        push cs
        pop  ds
        lea  si, [ErrorString]
        mov  cx, 7
        jmp  PrintStringAndHalt

PrintStringAndHalt:
        mov  ax,0b800h
        mov  es,ax
        mov  di,160
        rep  movsw
Halt:
        jmp   Halt

ErrorString:
        db 'S', 0ch, 'E', 0ch, 'r', 0ch, 'r', 0ch, 'o', 0ch, 'r', 0ch, '!', 0ch

        org     01fah
LBAOffsetForBootSector:
        dd      0h

        org     01feh
        dw      0aa55h

;******************************************************************************
;******************************************************************************
;******************************************************************************

DELAY_PORT           equ     0edh    ; Port to use for 1uS delay
KBD_CONTROL_PORT     equ     060h    ; 8042 control port     
KBD_STATUS_PORT      equ     064h    ; 8042 status port      
WRITE_DATA_PORT_CMD  equ     0d1h    ; 8042 command to write the data port
ENABLE_A20_CMD       equ     0dfh    ; 8042 command to enable A20

        org     200h
        jmp start
Em64String:
        db 'E', 0ch, 'm', 0ch, '6', 0ch, '4', 0ch, 'T', 0ch, ' ', 0ch, 'U', 0ch, 'n', 0ch, 's', 0ch, 'u', 0ch, 'p', 0ch, 'p', 0ch, 'o', 0ch, 'r', 0ch, 't', 0ch, 'e', 0ch, 'd', 0ch, '!', 0ch

start:  
        mov ax,cs
        mov ds,ax
        mov es,ax
        mov ss,ax
        mov sp,MyStack

;        mov ax,0b800h
;        mov es,ax
;        mov byte ptr es:[160],'a'
;        mov ax,cs
;        mov es,ax

        mov ebx,0
        lea edi,MemoryMap
MemMapLoop:
        mov eax,0e820h
        mov ecx,20
        mov edx,'SMAP'
        int 15h
        jc  MemMapDone
        add edi,20
        cmp ebx,0
        je  MemMapDone
        jmp MemMapLoop
MemMapDone:
        lea eax,MemoryMap
        sub edi,eax                         ; Get the address of the memory map
        mov dword ptr [MemoryMapSize],edi   ; Save the size of the memory map

        xor     ebx,ebx
        mov     bx,cs                       ; BX=segment
        shl     ebx,4                       ; BX="linear" address of segment base
        lea     eax,[GDT_BASE + ebx]        ; EAX=PHYSICAL address of gdt
        mov     dword ptr [gdtr + 2],eax    ; Put address of gdt into the gdtr
        lea     eax,[IDT_BASE + ebx]        ; EAX=PHYSICAL address of idt
        mov     dword ptr [idtr + 2],eax    ; Put address of idt into the idtr
        lea     edx,[MemoryMapSize + ebx]   ; Physical base address of the memory map

;        mov ax,0b800h
;        mov es,ax
;        mov byte ptr es:[162],'b'
;        mov ax,cs
;        mov es,ax

;
; Enable A20 Gate 
;

        mov ax,2401h                        ; Enable A20 Gate
        int 15h
        jnc A20GateEnabled                  ; Jump if it suceeded

;
; If INT 15 Function 2401 is not supported, then attempt to Enable A20 manually.
;

        call    Empty8042InputBuffer        ; Empty the Input Buffer on the 8042 controller
        jnz     Timeout8042                 ; Jump if the 8042 timed out
        out     DELAY_PORT,ax               ; Delay 1 uS
        mov     al,WRITE_DATA_PORT_CMD      ; 8042 cmd to write output port
        out     KBD_STATUS_PORT,al          ; Send command to the 8042
        call    Empty8042InputBuffer        ; Empty the Input Buffer on the 8042 controller
        jnz     Timeout8042                 ; Jump if the 8042 timed out
        mov     al,ENABLE_A20_CMD           ; gate address bit 20 on
        out     KBD_CONTROL_PORT,al         ; Send command to thre 8042
        call    Empty8042InputBuffer        ; Empty the Input Buffer on the 8042 controller
        mov     cx,25                       ; Delay 25 uS for the command to complete on the 8042
Delay25uS:
        out     DELAY_PORT,ax               ; Delay 1 uS
        loop    Delay25uS                       
Timeout8042:


A20GateEnabled:

;
; DISABLE INTERRUPTS - Entering Protected Mode
;

        cli                             

;        mov ax,0b800h
;        mov es,ax
;        mov byte ptr es:[164],'c'
;        mov ax,cs
;        mov es,ax

    lea eax, OffsetIn32BitProtectedMode
    add eax, 20000h + 6h
    mov dword ptr[OffsetIn32BitProtectedMode], eax

    lea eax, OffsetInLongMode
    add eax, 20000h + 6h
    mov dword ptr[OffsetInLongMode], eax

    ;
    ; load GDT
    ;
    db      66h     
    lgdt    fword ptr [gdtr]

    ;
    ; Enable Protect Mode (set CR0.PE=1)
    ;
    mov   eax, cr0        ; Read CR0.
    or    eax, 1h         ; Set PE=1
    mov   cr0, eax        ; Write CR0.
    db    066h
    db    0eah                        ; jmp far 16:32
OffsetIn32BitProtectedMode:
    dd    00000000h                   ; offset $+8   (In32BitProtectedMode)
    dw    10h                         ; selector  (flat CS)
In32BitProtectedMode:

;
; Entering Long Mode
;
    db   66h
    mov  ax, 8
    mov  ds, ax
    mov  es, ax
    mov  ss, ax

    ;
    ; Enable the 64-bit page-translation-table entries by
    ; setting CR4.PAE=1 (this is _required_ before activating
    ; long mode). Paging is not enabled until after long mode
    ; is enabled.
    ;
    db 0fh
    db 20h
    db 0e0h
;    mov eax, cr4
    bts eax, 5
    db 0fh
    db 22h
    db 0e0h
;    mov cr4, eax

    ;
    ; This is the Trapolean Page Tables that are guarenteed
    ;  under 4GB.
    ;
    ; Address Map:
    ;    10000 ~    12000 - efildr (loaded)
    ;    20000 ~    21000 - start64.com
    ;    21000 ~    22000 - efi64.com
    ;    22000 ~    90000 - efildr
    ;    90000 ~    96000 - 4G pagetable (will be reload later)
    ;
    db  0b8h
    dd  90000h
;    mov eax, 90000h
    mov cr3, eax

    ;
    ; Enable long mode (set EFER.LME=1).
    ;
    db  0b9h
    dd  0c0000080h
;    mov   ecx, 0c0000080h ; EFER MSR number.
    db 0fh
    db 32h
;    rdmsr                 ; Read EFER.
    db    0fh
    db    0bah
    db    0e8h
    db    08h
;    bts   eax, 8          ; Set LME=1.
    db 0fh
    db 30h
;    wrmsr                 ; Write EFER.

    ;
    ; Enable paging to activate long mode (set CR0.PG=1)
    ;
    mov   eax, cr0        ; Read CR0.
    db    0fh
    db    0bah
    db    0e8h
    db    01fh
;    bts   eax, 31         ; Set PG=1.
    mov   cr0, eax        ; Write CR0.
    jmp   GoToLongMode
GoToLongMode:

    db      067h
    db      0eah                ; Far Jump $+9:Selector to reload CS
OffsetInLongMode:
    dd      00000000            ;   $+9 Offset is ensuing instruction boundary
    dw      038h                ;   Selector is our code selector, 38h

InLongMode:
    db   66h
    mov     ax, 30h
    mov     ds, ax

    db   66h
    mov     ax, 18h
    mov     es, ax
    mov     ss, ax
    mov     ds, ax

    db 0bdh
    dd 400000h
;    mov ebp,000400000h                  ; Destination of EFILDR32
    db 0bbh
    dd 70000h
;    mov ebx,000070000h                  ; Length of copy

    ;
    ; load idt later
    ;
    db 48h
    db 33h
    db 0c0h
;    xor rax, rax
    db 66h
    mov ax, offset idtr
    db 48h
    db 05h
    dd 20000h
;    add rax, 20000h

    db 0fh
    db 01h
    db 18h
;    lidt    fword ptr [rax]

    db 48h
    db 0c7h
    db 0c0h
    dd 21000h
;   mov rax, 21000h
    db 50h
;   push rax

; ret
    db 0c3h

Empty8042InputBuffer:
        mov cx,0
Empty8042Loop:
        out     DELAY_PORT,ax               ; Delay 1us
        in      al,KBD_STATUS_PORT          ; Read the 8042 Status Port
        and     al,02h                      ; Check the Input Buffer Full Flag
        loopnz  Empty8042Loop               ; Loop until the input buffer is empty or a timout of 65536 uS
        ret

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; data
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

        align 02h

gdtr    dw GDT_END - GDT_BASE - 1   ; GDT limit
        dd 0                        ; (GDT base gets set above)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;   global descriptor table (GDT)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

        align 02h

public GDT_BASE
GDT_BASE:
; null descriptor
NULL_SEL            equ $-GDT_BASE          ; Selector [0x0]
        dw 0            ; limit 15:0
        dw 0            ; base 15:0
        db 0            ; base 23:16
        db 0            ; type
        db 0            ; limit 19:16, flags
        db 0            ; base 31:24

; linear data segment descriptor
LINEAR_SEL      equ $-GDT_BASE          ; Selector [0x8]
        dw 0FFFFh       ; limit 0xFFFFF
        dw 0            ; base 0
        db 0
        db 092h         ; present, ring 0, data, expand-up, writable
        db 0CFh                 ; page-granular, 32-bit
        db 0

; linear code segment descriptor
LINEAR_CODE_SEL equ $-GDT_BASE          ; Selector [0x10]
        dw 0FFFFh       ; limit 0xFFFFF
        dw 0            ; base 0
        db 0
        db 09Ah         ; present, ring 0, data, expand-up, writable
        db 0CFh                 ; page-granular, 32-bit
        db 0

; system data segment descriptor
SYS_DATA_SEL    equ $-GDT_BASE          ; Selector [0x18]
        dw 0FFFFh       ; limit 0xFFFFF
        dw 0            ; base 0
        db 0
        db 092h         ; present, ring 0, data, expand-up, writable
        db 0CFh                 ; page-granular, 32-bit
        db 0

; system code segment descriptor
SYS_CODE_SEL    equ $-GDT_BASE          ; Selector [0x20]
        dw 0FFFFh       ; limit 0xFFFFF
        dw 0            ; base 0
        db 0
        db 09Ah         ; present, ring 0, data, expand-up, writable
        db 0CFh                 ; page-granular, 32-bit
        db 0

; spare segment descriptor
SPARE3_SEL  equ $-GDT_BASE          ; Selector [0x28]
        dw 0            ; limit 0xFFFFF
        dw 0            ; base 0
        db 0
        db 0            ; present, ring 0, data, expand-up, writable
        db 0            ; page-granular, 32-bit
        db 0

;
; system data segment descriptor
;
SYS_DATA64_SEL    equ $-GDT_BASE          ; Selector [0x30]
        dw 0FFFFh       ; limit 0xFFFFF
        dw 0            ; base 0
        db 0
        db 092h         ; P | DPL [1..2] | 1   | 1   | C | R | A
        db 0CFh         ; G | D   | L    | AVL | Segment [19..16]
        db 0

;
; system code segment descriptor
;
SYS_CODE64_SEL    equ $-GDT_BASE          ; Selector [0x38]
        dw 0FFFFh       ; limit 0xFFFFF
        dw 0            ; base 0
        db 0
        db 09Ah         ; P | DPL [1..2] | 1   | 1   | C | R | A
        db 0AFh         ; G | D   | L    | AVL | Segment [19..16]
        db 0

; spare segment descriptor
SPARE4_SEL  equ $-GDT_BASE            ; Selector [0x40]
        dw 0            ; limit 0xFFFFF
        dw 0            ; base 0
        db 0
        db 0            ; present, ring 0, data, expand-up, writable
        db 0            ; page-granular, 32-bit
        db 0

GDT_END:

        align 02h



idtr            dw IDT_END - IDT_BASE - 1   ; IDT limit
        dq 0                        ; (IDT base gets set above)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;   interrupt descriptor table (IDT)
;
;   Note: The hardware IRQ's specified in this table are the normal PC/AT IRQ
;       mappings.  This implementation only uses the system timer and all other
;       IRQs will remain masked.  The descriptors for vectors 33+ are provided
;       for convenience.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;idt_tag db "IDT",0     
        align 02h

public IDT_BASE
IDT_BASE:
; divide by zero (INT 0)
DIV_ZERO_SEL        equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; debug exception (INT 1)
DEBUG_EXCEPT_SEL    equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; NMI (INT 2)
NMI_SEL             equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; soft breakpoint (INT 3)
BREAKPOINT_SEL      equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; overflow (INT 4)
OVERFLOW_SEL        equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; bounds check (INT 5)
BOUNDS_CHECK_SEL    equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; invalid opcode (INT 6)
INVALID_OPCODE_SEL  equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; device not available (INT 7)
DEV_NOT_AVAIL_SEL   equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; double fault (INT 8)
DOUBLE_FAULT_SEL    equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; Coprocessor segment overrun - reserved (INT 9)
RSVD_INTR_SEL1      equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; invalid TSS (INT 0ah)
INVALID_TSS_SEL     equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; segment not present (INT 0bh)
SEG_NOT_PRESENT_SEL equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; stack fault (INT 0ch)
STACK_FAULT_SEL     equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; general protection (INT 0dh)
GP_FAULT_SEL        equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; page fault (INT 0eh)
PAGE_FAULT_SEL      equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; Intel reserved - do not use (INT 0fh)
RSVD_INTR_SEL2      equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; floating point error (INT 10h)
FLT_POINT_ERR_SEL   equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; alignment check (INT 11h)
ALIGNMENT_CHECK_SEL equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; machine check (INT 12h)
MACHINE_CHECK_SEL   equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; SIMD floating-point exception (INT 13h)
SIMD_EXCEPTION_SEL  equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; 85 unspecified descriptors, First 12 of them are reserved, the rest are avail
        db (85 * 16) dup(0)
        
; IRQ 0 (System timer) - (INT 68h)
IRQ0_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 1 (8042 Keyboard controller) - (INT 69h)
IRQ1_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; Reserved - IRQ 2 redirect (IRQ 2) - DO NOT USE!!! - (INT 6ah)
IRQ2_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 3 (COM 2) - (INT 6bh)
IRQ3_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 4 (COM 1) - (INT 6ch)
IRQ4_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 5 (LPT 2) - (INT 6dh)
IRQ5_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 6 (Floppy controller) - (INT 6eh)
IRQ6_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 7 (LPT 1) - (INT 6fh)
IRQ7_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 8 (RTC Alarm) - (INT 70h)
IRQ8_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 9 - (INT 71h)
IRQ9_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 10 - (INT 72h)
IRQ10_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 11 - (INT 73h)
IRQ11_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 12 (PS/2 mouse) - (INT 74h)
IRQ12_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 13 (Floating point error) - (INT 75h)
IRQ13_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 14 (Secondary IDE) - (INT 76h)
IRQ14_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

; IRQ 15 (Primary IDE) - (INT 77h)
IRQ15_SEL            equ $-IDT_BASE
        dw 0            ; offset 15:0
        dw SYS_CODE64_SEL ; selector 15:0
        db 0            ; 0 for interrupt gate
        db 0eh OR 80h   ; (10001110)type = 386 interrupt gate, present
        dw 0            ; offset 31:16
        dd 0            ; offset 63:32
        dd 0            ; 0 for reserved

IDT_END:

        align 02h

MemoryMapSize   dd  0
MemoryMap   dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0

        dd  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
        dd  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

        org 0fe0h
MyStack:    
        ; below is the pieces of the IVT that is used to redirect INT 68h - 6fh
        ;    back to INT 08h - 0fh  when in real mode...  It is 'org'ed to a
        ;    known low address (20f00) so it can be set up by PlMapIrqToVect in
        ;    8259.c
                
        int 8
        iret
        
        int 9
        iret
        
        int 10
        iret
        
        int 11
        iret
        
        int 12
        iret
        
        int 13
        iret
        
        int 14
        iret
        
        int 15
        iret
        
        
        org 0ffeh
BlockSignature:
        dw  0aa55h

        end