/* subsegs.c - subsegments - Copyright (C) 1987, 1990, 1991 Free Software Foundation, Inc. This file is part of GAS, the GNU Assembler. GAS 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 1, or (at your option) any later version. GAS 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 GAS; see the file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ /* static const char rcsid[] = "$Id$"; */ /* * Segments & sub-segments. */ #include "as.h" #include "subsegs.h" #include "obstack.h" frchainS* frchain_root, * frchain_now, /* Commented in "subsegs.h". */ * data0_frchainP; char * const /* in: segT out: char* */ seg_name[] = { "absolute", "text", "data", "bss", "unknown", "absent", "pass1", "ASSEMBLER-INTERNAL-LOGIC-ERROR!", "bignum/flonum", "difference", "debug", "transfert vector preload", "transfert vector postload", "register", "", }; /* Used by error reporters, dumpers etc. */ void subsegs_begin() { /* Check table(s) seg_name[], seg_N_TYPE[] is in correct order */ know( SEG_ABSOLUTE == 0 ); know( SEG_TEXT == 1 ); know( SEG_DATA == 2 ); know( SEG_BSS == 3 ); know( SEG_UNKNOWN == 4 ); know( SEG_ABSENT == 5 ); know( SEG_PASS1 == 6 ); know( SEG_GOOF == 7 ); know( SEG_BIG == 8 ); know( SEG_DIFFERENCE == 9 ); know( SEG_DEBUG == 10 ); know( SEG_NTV == 11 ); know( SEG_PTV == 12 ); know( SEG_REGISTER == 13 ); know( SEG_MAXIMUM_ORDINAL == SEG_REGISTER ); know( segment_name (SEG_MAXIMUM_ORDINAL + 1) [0] == 0 ); obstack_begin( &frags, 5000); frchain_root = NULL; frchain_now = NULL; /* Warn new_subseg() that we are booting. */ /* Fake up 1st frag. */ /* It won't be used=> is ok if obstack... */ /* pads the end of it for alignment. */ frag_now=(fragS *)obstack_alloc(&frags,SIZEOF_STRUCT_FRAG); /* obstack_1blank( &frags, SIZEOF_STRUCT_FRAG, & frag_now ); */ /* This 1st frag will not be in any frchain. */ /* We simply give subseg_new somewhere to scribble. */ now_subseg = 42; /* Lie for 1st call to subseg_new. */ subseg_new (SEG_DATA, 0); /* .data 0 */ data0_frchainP = frchain_now; } /* * subseg_change() * * Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the * subsegment. If we are already in the correct subsegment, change nothing. * This is used eg as a worker for subseg_new [which does make a new frag_now] * and for changing segments after we have read the source. We construct eg * fixSs even after the source file is read, so we do have to keep the * segment context correct. */ void subseg_change (seg, subseg) register segT seg; register int subseg; { now_seg = seg; now_subseg = subseg; if (seg == SEG_DATA) { seg_fix_rootP = & data_fix_root; seg_fix_tailP = & data_fix_tail; } else { know (seg == SEG_TEXT); seg_fix_rootP = & text_fix_root; seg_fix_tailP = & text_fix_tail; } } /* * subseg_new() * * If you attempt to change to the current subsegment, nothing happens. * * In: segT, subsegT code for new subsegment. * frag_now -> incomplete frag for current subsegment. * If frag_now==NULL, then there is no old, incomplete frag, so * the old frag is not closed off. * * Out: now_subseg, now_seg updated. * Frchain_now points to the (possibly new) struct frchain for this * sub-segment. * Frchain_root updated if needed. */ void subseg_new (seg, subseg) /* begin assembly for a new sub-segment */ register segT seg; /* SEG_DATA or SEG_TEXT */ register subsegT subseg; { long tmp; /* JF for obstack alignment hacking */ know( seg == SEG_DATA || seg == SEG_TEXT ); if (seg != now_seg || subseg != now_subseg) { /* we just changed sub-segments */ register frchainS * frcP; /* crawl frchain chain */ register frchainS** lastPP; /* address of last pointer */ frchainS * newP; /* address of new frchain */ register fragS * former_last_fragP; register fragS * new_fragP; if (frag_now) /* If not bootstrapping. */ { frag_now -> fr_fix = obstack_next_free(& frags) - frag_now -> fr_literal; frag_wane(frag_now); /* Close off any frag in old subseg. */ } /* * It would be nice to keep an obstack for each subsegment, if we swap * subsegments a lot. Hence we would have much fewer frag_wanes(). */ { obstack_finish( &frags); /* * If we don't do the above, the next object we put on obstack frags * will appear to start at the fr_literal of the current frag. * Also, above ensures that the next object will begin on a * address that is aligned correctly for the engine that runs * this program. */ } subseg_change (seg, (int)subseg); /* * Attempt to find or make a frchain for that sub seg. * Crawl along chain of frchainSs, begins @ frchain_root. * If we need to make a frchainS, link it into correct * position of chain rooted in frchain_root. */ for (frcP = * (lastPP = & frchain_root); frcP && (int)(frcP -> frch_seg) <= (int)seg; frcP = * ( lastPP = & frcP -> frch_next) ) { if ( (int)(frcP -> frch_seg) == (int)seg && frcP -> frch_subseg >= subseg) { break; } } /* * frcP: Address of the 1st frchainS in correct segment with * frch_subseg >= subseg. * We want to either use this frchainS, or we want * to insert a new frchainS just before it. * * If frcP==NULL, then we are at the end of the chain * of frchainS-s. A NULL frcP means we fell off the end * of the chain looking for a * frch_subseg >= subseg, so we * must make a new frchainS. * * If we ever maintain a pointer to * the last frchainS in the chain, we change that pointer * ONLY when frcP==NULL. * * lastPP: Address of the pointer with value frcP; * Never NULL. * May point to frchain_root. * */ if ( ! frcP || ( (int)(frcP -> frch_seg) > (int)seg || frcP->frch_subseg > subseg)) /* Kinky logic only works with 2 segments. */ { /* * This should be the only code that creates a frchainS. */ newP=(frchainS *)obstack_alloc(&frags,sizeof(frchainS)); /* obstack_1blank( &frags, sizeof(frchainS), &newP); */ /* This begines on a good boundary */ /* because a obstack_done() preceeded it. */ /* It implies an obstack_done(), so we */ /* expect the next object allocated to */ /* begin on a correct boundary. */ *lastPP = newP; newP -> frch_next = frcP; /* perhaps NULL */ (frcP = newP) -> frch_subseg = subseg; newP -> frch_seg = seg; newP -> frch_last = NULL; } /* * Here with frcP ->ing to the frchainS for subseg. */ frchain_now = frcP; /* * Make a fresh frag for the subsegment. */ /* We expect this to happen on a correct */ /* boundary since it was proceeded by a */ /* obstack_done(). */ tmp=obstack_alignment_mask(&frags); /* JF disable alignment */ obstack_alignment_mask(&frags)=0; frag_now=(fragS *)obstack_alloc(&frags,SIZEOF_STRUCT_FRAG); obstack_alignment_mask(&frags)=tmp; /* know( frags . obstack_c_next_free == frag_now -> fr_literal ); */ /* But we want any more chars to come */ /* immediately after the structure we just made. */ new_fragP = frag_now; new_fragP -> fr_next = NULL; /* * Append new frag to current frchain. */ former_last_fragP = frcP -> frch_last; if (former_last_fragP) { know( former_last_fragP -> fr_next == NULL ); know( frchain_now -> frch_root ); former_last_fragP -> fr_next = new_fragP; } else { frcP -> frch_root = new_fragP; } frcP -> frch_last = new_fragP; } /* if (changing subsegments) */ } /* subseg_new() */ /* * Local Variables: * comment-column: 0 * fill-column: 131 * End: */ /* end: subsegs.c */