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/* frags.c - manage frags -
Copyright (C) 1987, 1990, 1991, 1992 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 2, 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. */
#ifndef lint
static char rcsid[] = "$Id: frags.c,v 1.1 1995/10/18 08:38:58 deraadt Exp $";
#endif
#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 */
memset(frag_now, '\0', 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;
#ifndef NO_LISTING
{
extern struct list_info_struct *listing_tail;
frag_now->line = listing_tail;
}
#endif
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 of frags.c */
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