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/* preserve.c - preserve opererands or registers in use for bcc */
/* Copyright (C) 1992 Bruce Evans */
#include "bcc.h"
#include "gencode.h"
#include "reg.h"
#include "type.h"
#include "scan.h"
/* change stack ptr without changing condition codes */
PUBLIC void changesp(newsp, absflag)
offset_T newsp;
bool_pt absflag;
{
if (newsp != sp || ((bool_t) absflag && switchnow != NULL))
{
#ifdef FRAMEPOINTER
if (newsp != framep || (!(bool_t) absflag && switchnow != NULL))
{
int off;
outleasp();
if (!(bool_t) absflag && switchnow != NULL)
outswoffset(off = newsp);
else
outoffset(off = newsp - framep);
#ifndef NO_DEL_PUSH
if (optimise && !callersaves && off < 0)
{
outstr("+");
outstr(funcname);
outstr(".off");
}
#endif
outindframereg();
outnl();
}
else
regtransfer(FRAMEREG, STACKREG);
sp = newsp;
if (framep == 0)
bugerror("no frame pointer");
#else
# ifdef I8088
outleasp();
outoffset(newsp - sp);
outindstackreg();
outnl();
# else
modstk(newsp); /* this should preserve CC */
# endif
#endif /* FRAMEPOINTER */
}
}
/* load source to any while preserving target */
PUBLIC void loadpres(source, target)
struct symstruct *source;
struct symstruct *target;
{
store_t regmark;
if (target->storage & ALLDATREGS)
{
if (source->type->scalar & CHAR)
{
push(target);
load(source, DREG);
}
else
load(source, getindexreg());
}
else
{
regmark = reguse;
reguse |= target->storage;
loadany(source);
reguse = regmark;
}
}
/* change stack ptr */
PUBLIC void modstk(newsp)
offset_T newsp;
{
if (newsp != sp)
{
#ifdef FRAMEPOINTER
if (newsp != framep || framep == 0 || switchnow != NULL)
addconst(newsp - sp, STACKREG);
else
regtransfer(FRAMEREG, STACKREG);
#else
# ifdef I8088
addconst(newsp - sp, STACKREG);
# else
outleasp();
outoffset(newsp - sp);
outncspregname();
# endif
#endif
sp = newsp;
}
}
/* preserve target without changing source */
PUBLIC void pres2(source, target)
struct symstruct *source;
struct symstruct *target;
{
if (target->storage & allregs)
{
if (target->storage & (allregs - allindregs) /* XXX */ ||
(target->indcount == 0 &&
target->type->scalar & (DLONG | RSCALAR)))
push(target); /* XXX - perhaps not float */
else if (((target->storage | reguse) & allindregs) == allindregs)
{
loadpres(target, source);
push(target);
}
else
reguse |= target->storage;
}
}
/* preserve source */
PUBLIC void preserve(source)
struct symstruct *source;
{
if (source->storage & allregs)
{
if (source->storage & (allregs - allindregs) /* XXX */ ||
((source->storage | reguse) & allindregs) == allindregs)
push(source);
else
reguse |= source->storage;
}
}
/* preserve lvalue target without changing source or target */
PUBLIC store_pt preslval(source, target)
struct symstruct *source;
struct symstruct *target;
{
store_pt regpushed;
if (target->indcount == 0)
reguse &= ~target->storage;
else
reguse = (target->storage | reguse) & allindregs;
if (!((source->type->scalar | target->type->scalar) & (DLONG | RSCALAR))
|| reguse != allindregs)
return 0; /* XXX - perhaps not float */
reguse = source->storage | target->storage; /* free one other than s/t */
pushreg(regpushed = getindexreg());
reguse = ~(store_t) regpushed & allindregs;
return regpushed;
}
PUBLIC void recovlist(reglist)
store_pt reglist;
{
poplist(reglist);
reguse |= (store_t) reglist;
}
#ifdef I8088
PRIVATE smalin_t regoffset[] = {0, 0, 0, 1, 2, 3, 0, 0, 0, 4, 5};
/* CONSTANT, BREG, ax = DREG, bx = INDREG0, si = INDREG1, di = INDREG2 */
/* LOCAL, GLOBAL, STACKREG, cx = DATREG1, dx = DATREG2 */
#endif
#ifdef MC6809
PRIVATE smalin_t regoffset[] = {0, 0, 0, 1, 3, 2};
/* CONSTANT, BREG, DREG, XREG = INDREG0, UREG = INDREG1, YREG = INDREG2 */
#endif
PUBLIC void savereturn(savelist, saveoffset)
store_pt savelist;
offset_T saveoffset;
{
store_t reg;
smalin_t *regoffptr;
offset_T spoffset;
if (savelist == 0)
return;
#ifdef MC6809 /* must check this */
if (savelist == XREG || savelist == INDREG1)
saveoffset -= accregsize; /* patch for DREG/YREG not saved */
#endif
for (reg = 1, regoffptr = regoffset; reg != 0; ++regoffptr, reg <<= 1)
if (reg & savelist)
{
outstore();
spoffset = saveoffset + *regoffptr * maxregsize;
#ifdef I8088
# ifdef FRAMEPOINTER
if (switchnow != NULL)
outswoffset(spoffset);
else
outoffset(spoffset - framep);
outindframereg();
# else
outoffset(spoffset - sp);
outindstackreg();
# endif
outncregname(reg);
#endif
#ifdef MC6809
if (reg == YREG)
bumplc();
outregname(reg);
outtab();
outoffset(spoffset - sp);
outncspregname();
#endif
}
}
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