diff options
Diffstat (limited to 'gas/frags.c')
| -rw-r--r-- | gas/frags.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/gas/frags.c b/gas/frags.c new file mode 100644 index 0000000000..3526603f1e --- /dev/null +++ b/gas/frags.c @@ -0,0 +1,285 @@ +/* frags.c - manage frags - + 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[] = "$Id$"; */ + +#include "as.h" +#include "subsegs.h" +#include "obstack.h" + +struct obstack frags; /* All, and only, frags live here. */ + +fragS zero_address_frag = { + 0, /* fr_address */ + NULL, /* fr_next */ + 0, /* fr_fix */ + 0, /* fr_var */ + 0, /* fr_symbol */ + 0, /* fr_offset */ + NULL, /* fr_opcode */ + rs_fill, /* fr_type */ + 0, /* fr_subtype */ + 0, /* fr_pcrel_adjust */ + 0, /* fr_bsr */ + 0 /* fr_literal [0] */ +}; + +fragS bss_address_frag = { + 0, /* fr_address. Gets filled in to make up + sy_value-s. */ + NULL, /* fr_next */ + 0, /* fr_fix */ + 0, /* fr_var */ + 0, /* fr_symbol */ + 0, /* fr_offset */ + NULL, /* fr_opcode */ + rs_fill, /* fr_type */ + 0, /* fr_subtype */ + 0, /* fr_pcrel_adjust */ + 0, /* fr_bsr */ + 0 /* fr_literal [0] */ +}; + +/* + * frag_grow() + * + * Internal. + * Try to augment current frag by nchars chars. + * If there is no room, close of the current frag with a ".fill 0" + * and begin a new frag. Unless the new frag has nchars chars available + * do not return. Do not set up any fields of *now_frag. + */ +static void frag_grow(nchars) +unsigned int nchars; +{ + if (obstack_room (&frags) < nchars) { + unsigned int n,oldn; + long oldc; + + frag_wane(frag_now); + frag_new(0); + oldn=(unsigned)-1; + oldc=frags.chunk_size; + frags.chunk_size=2*nchars; + while((n=obstack_room(&frags))<nchars && n<oldn) { + frag_wane(frag_now); + frag_new(0); + oldn=n; + } + frags.chunk_size=oldc; + } + if (obstack_room (&frags) < nchars) + as_fatal("Can't extend frag %d. chars", nchars); +} /* frag_grow() */ + +/* + * frag_new() + * + * Call this to close off a completed frag, and start up a new (empty) + * frag, in the same subsegment as the old frag. + * [frchain_now remains the same but frag_now is updated.] + * Because this calculates the correct value of fr_fix by + * looking at the obstack 'frags', it needs to know how many + * characters at the end of the old frag belong to (the maximal) + * fr_var: the rest must belong to fr_fix. + * It doesn't actually set up the old frag's fr_var: you may have + * set fr_var == 1, but allocated 10 chars to the end of the frag: + * in this case you pass old_frags_var_max_size == 10. + * + * Make a new frag, initialising some components. Link new frag at end + * of frchain_now. + */ +void frag_new(old_frags_var_max_size) +int old_frags_var_max_size; /* Number of chars (already allocated on + obstack frags) */ + /* in variable_length part of frag. */ +{ + register fragS * former_last_fragP; +/* char *throw_away_pointer; JF unused */ + register frchainS * frchP; + long tmp; /* JF */ + + frag_now->fr_fix = (char *) (obstack_next_free (&frags)) - + (frag_now->fr_literal) - old_frags_var_max_size; + /* Fix up old frag's fr_fix. */ + + obstack_finish (&frags); + /* This will align the obstack so the */ + /* next struct we allocate on it will */ + /* begin at a correct boundary. */ + frchP = frchain_now; + know (frchP); + former_last_fragP = frchP->frch_last; + know (former_last_fragP); + know (former_last_fragP == frag_now); + obstack_blank (&frags, SIZEOF_STRUCT_FRAG); + /* We expect this will begin at a correct */ + /* boundary for a struct. */ + tmp=obstack_alignment_mask(&frags); + obstack_alignment_mask(&frags)=0; /* Turn off alignment */ + /* If we ever hit a machine + where strings must be + aligned, we Lose Big */ + frag_now=(fragS *)obstack_finish(&frags); + obstack_alignment_mask(&frags)=tmp; /* Restore alignment */ + + /* Just in case we don't get zero'd bytes */ + bzero(frag_now, SIZEOF_STRUCT_FRAG); + +/* obstack_unaligned_done (&frags, &frag_now); */ +/* know (frags.obstack_c_next_free == frag_now->fr_literal); */ + /* Generally, frag_now->points to an */ + /* address rounded up to next alignment. */ + /* However, characters will add to obstack */ + /* frags IMMEDIATELY after the struct frag, */ + /* even if they are not starting at an */ + /* alignment address. */ + former_last_fragP->fr_next = frag_now; + frchP->frch_last = frag_now; + frag_now->fr_next = NULL; +} /* frag_new() */ + +/* + * frag_more() + * + * Start a new frag unless we have n more chars of room in the current frag. + * Close off the old frag with a .fill 0. + * + * Return the address of the 1st char to write into. Advance + * frag_now_growth past the new chars. + */ + +char *frag_more (nchars) +int nchars; +{ + register char *retval; + + frag_grow (nchars); + retval = obstack_next_free (&frags); + obstack_blank_fast (&frags, nchars); + return (retval); +} /* frag_more() */ + +/* + * frag_var() + * + * Start a new frag unless we have max_chars more chars of room in the current frag. + * Close off the old frag with a .fill 0. + * + * Set up a machine_dependent relaxable frag, then start a new frag. + * Return the address of the 1st char of the var part of the old frag + * to write into. + */ + +char *frag_var(type, max_chars, var, subtype, symbol, offset, opcode) +relax_stateT type; +int max_chars; +int var; +relax_substateT subtype; +symbolS *symbol; +long offset; +char *opcode; +{ + register char *retval; + + frag_grow (max_chars); + retval = obstack_next_free (&frags); + obstack_blank_fast (&frags, max_chars); + frag_now->fr_var = var; + frag_now->fr_type = type; + frag_now->fr_subtype = subtype; + frag_now->fr_symbol = symbol; + frag_now->fr_offset = offset; + frag_now->fr_opcode = opcode; + /* default these to zero. */ + frag_now->fr_pcrel_adjust = 0; + frag_now->fr_bsr = 0; + frag_new (max_chars); + return (retval); +} /* frag_var() */ + +/* + * frag_variant() + * + * OVE: This variant of frag_var assumes that space for the tail has been + * allocated by caller. + * No call to frag_grow is done. + * Two new arguments have been added. + */ + +char *frag_variant(type, max_chars, var, subtype, symbol, offset, opcode, pcrel_adjust,bsr) + relax_stateT type; + int max_chars; + int var; + relax_substateT subtype; + symbolS *symbol; + long offset; + char *opcode; + int pcrel_adjust; + char bsr; +{ + register char *retval; + +/* frag_grow (max_chars); */ + retval = obstack_next_free (&frags); +/* obstack_blank_fast (&frags, max_chars); */ /* OVE: so far the only diff */ + frag_now->fr_var = var; + frag_now->fr_type = type; + frag_now->fr_subtype = subtype; + frag_now->fr_symbol = symbol; + frag_now->fr_offset = offset; + frag_now->fr_opcode = opcode; + frag_now->fr_pcrel_adjust = pcrel_adjust; + frag_now->fr_bsr = bsr; + frag_new (max_chars); + return (retval); +} /* frag_variant() */ + +/* + * frag_wane() + * + * Reduce the variable end of a frag to a harmless state. + */ +void frag_wane(fragP) +register fragS * fragP; +{ + fragP->fr_type = rs_fill; + fragP->fr_offset = 0; + fragP->fr_var = 0; +} + +/* + * frag_align() + * + * Make a frag for ".align foo,bar". Call is "frag_align (foo,bar);". + * Foo & bar are absolute integers. + * + * Call to close off the current frag with a ".align", then start a new + * (so far empty) frag, in the same subsegment as the last frag. + */ + +void frag_align(alignment, fill_character) +int alignment; +int fill_character; +{ + *(frag_var (rs_align, 1, 1, (relax_substateT)0, (symbolS *)0, + (long)alignment, (char *)0)) = fill_character; +} /* frag_align() */ + +/* end: frags.c */ |
