/* subsegs.c - subsegments -
Copyright (C) 1987 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)
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. */
* Segments & sub-segments.
#include "struc-symbol.h"
* frchain_now
, /* Commented in "subsegs.h". */
const int /* in: segT out: N_TYPE bits */
char * const /* in: segT out: char* */
"ASSEMBLER-INTERNAL-LOGIC-ERROR!",
}; /* Used by error reporters, dumpers etc. */
const segT N_TYPE_seg
[N_TYPE
+2] = /* N_TYPE == 0x1E = 32-2 */
SEG_UNKNOWN
, /* N_UNDF == 0 */
SEG_ABSOLUTE
, /* N_ABS == 2 */
SEG_TEXT
, /* N_TEXT == 4 */
SEG_DATA
, /* N_DATA == 6 */
SEG_BSS
, /* N_BSS == 8 */
SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
,
SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
,
SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
, SEG_GOOF
/* Check table(s) seg_name[], seg_N_TYPE[] is in correct order */
know( SEG_ABSOLUTE
==0 );
know( SEG_DIFFERENCE
==9 );
know( SEG_MAXIMUM_ORDINAL
== SEG_DIFFERENCE
);
know( seg_name
[(int) SEG_MAXIMUM_ORDINAL
+ 1] [0] == 0 );
obstack_begin( &frags
, 5000);
frchain_now
= NULL
; /* Warn new_subseg() that we are booting. */
/* 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
;
* 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.
subseg_change (seg
, subseg
)
seg_fix_rootP
= & data_fix_root
;
seg_fix_rootP
= & text_fix_root
;
* 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
* Frchain_root updated if needed.
subseg_new (seg
, subseg
) /* begin assembly for a new sub-segment */
register segT seg
; /* SEG_DATA or SEG_TEXT */
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().
* 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
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
);
&& (int)(frcP
-> frch_seg
) <= (int)seg
;
frcP
= * ( lastPP
= & frcP
-> frch_next
)
if ( (int)(frcP
-> frch_seg
) == (int)seg
&& frcP
-> frch_subseg
>= subseg
)
* frcP: Address of the 1st frchainS in correct segment with
* 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
* lastPP: Address of the pointer with value frcP;
* May point to frchain_root.
|| ( (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. */
newP
-> frch_next
= frcP
; /* perhaps NULL */
(frcP
= newP
) -> frch_subseg
= subseg
;
newP
-> frch_last
= NULL
;
* Here with frcP ->ing to the frchainS for subseg.
* Make a fresh frag for the subsegment.
/* We expect this to happen on a correct */
/* boundary since it was proceeded by a */
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
-> fr_next
= NULL
;
* Append new frag to current frchain.
former_last_fragP
= frcP
-> frch_last
;
know( former_last_fragP
-> fr_next
== NULL
);
know( frchain_now
-> frch_root
);
former_last_fragP
-> fr_next
= new_fragP
;
frcP
-> frch_root
= new_fragP
;
frcP
-> frch_last
= new_fragP
;
} /* if (changing subsegments) */