-#endif
- 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));
- memset(newP, sizeof(frchainS), 0);
- /* 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() */