Trailing-Edge
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PDP-10 Archives
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SRI_NIC_PERM_FS_1_19910112
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kccdist/kcc/cccode.c
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/* CCCODE.C - Emit pseudo-code into peephole buffer
**
** All changes after version 146 (8/8/85), unless otherwise specified, are
** Copyright 1985, 1986 by Ken Harrenstien, SRI International.
**
** cccode -- Emit instructions into the peephole buffer for KCC
** (C) 1981 K. Chen
*/
#include "cc.h"
#include "ccgen.h"
#include <string.h> /* For memcpy, memcmp */
/* Imported functions */
extern char *calloc();
extern PCODE *findrset(); /* CCOPT */
extern void findconst(), optlsh(); /* CCOPT */
extern int rinreg(), rinaddr(), rmodreg(); /* CCOPT */
extern void outc(), realcode(), outlab(); /* CCOUT */
extern void cleanlabs(), freelabel(); /* CCSYM */
/* Exported functions */
PCODE *before(), *after(), *newcode();
void fixprev(), flushcode(), flspop();
void codek0(), codek4(), code4s(),
code0(), code1(), code2(), code4(), code5(),
code6(), code7(), code8(), code9(), code10(),
code11(), code12(), code13(), code14(), code15(),
code16(), code17(),
codestr(), codlabel(), codgolab();
/* Internal functions */
static void flsprev();
/* Debugging routines.
** SHOALL and SHOCURCOD are intended to be called directly by
** IDDT during debugging, e.g. as in PUSHJ 17,SHOALL$X
*/
static void shoall(), shocurcod(), shocod(), shopcod(),
shohdr(), shocum(), shocmp();
static void
shoall() { shocod(stderr); }
static void
shocurcod() { shopcod(stderr, previous, codes-previous); }
static void
shohdr() /* Called at start of each CODEnn function */
{
/* fprintf(fpho,"----------\n"); */ /* Nothing for now */
}
static void
shosum()
{
fprintf(fpho, "------ Current buffer -------\n");
shocod(fpho);
}
static void
shocod(f)
FILE *f;
{
int i;
for (i = mincode; i < maxcode; i++)
shopcod(f, &codes[i&(MAXCODE-1)], i&(MAXCODE-1));
}
char *shoskt[] = { /* Indexed by POF_OPSKIP field */
"", "A", "E", "N", "L", "GE", "G", "LE"
};
/* SHOPCOD - Show one pseudo-code entry
** Used as auxiliary for other debug printing routines, never called
** directly by IDDT.
*/
static void
shopcod(f,p,idx)
FILE *f;
PCODE *p;
{
unsigned int op, i;
char *s;
fprintf(f,"codes[%d] %6o/ %4o %5o %2o %6o %6o %2o %o+%o\n",
idx, p, p->Ptype, p->Pop, p->Preg, p->Pptr,
p->Poffset, p->Pindex, p->Pdouble1, p->Pdouble2);
/* Output value of Pop field */
op = p->Pop;
fprintf(f,"\t%s", popostr[op&POF_OPCODE]);
if (op&(~POF_OPCODE)) {
if (op&POF_ISSKIP) fprintf(f,"+skp");
if (i = (op&POF_OPSKIP)) fprintf(f,"+%s", shoskt[i>>POF_OPSKIP_SHF]);
if (op&POF_BOTH) fprintf(f, "+B");
}
/* Output value of Ptype field */
fprintf(f, " <");
if (p->Ptype&PTF_IMM) fprintf(f,"Imm,");
if (p->Ptype&PTF_SKIPPED) fprintf(f,"Skipped,");
if (p->Ptype&PTF_IND) fprintf(f,"Indirect");
i = (p->Ptype&PTF_ADRMODE); /* Get addressing mode */
/* Now interpret the rest of the instruction according to mode */
switch (i) {
case PTA_ONEREG: /* no address, just register */
fprintf(f, "> ONEREG R=%o,", p->Preg);
break;
case PTA_REGIS: /* register to register */
fprintf(f, "> REGIS R=%o, R=%o", p->Preg, p->Pr2);
break;
case PTA_MINDEXED: /* addr+offset(index) */
fprintf(f, "> MINDEXED R=%o, Addr=%s+%o(%o) siz %o", p->Preg,
(p->Pptr ? p->Pptr->Sname : ""),
p->Poffset, p->Pindex, p->Pbsize);
break;
case PTA_BYTEPOINT: /* [bsize,,addr+offset(index)] */
fprintf(f, "> BYTEPOINT R=%o, BP=[%o,,%s+%o(%o)]", p->Preg,
p->Pbsize,
(p->Pptr ? p->Pptr->Sname : ""),
p->Poffset,
p->Pindex);
break;
case PTA_PCONST: /* [<pointer of addr+offset+bsize>] */
if (p->Pbsize)
fprintf(f, "> PCONST R=%o, bptr%d=[%s+%o]", p->Preg,
p->Pbsize,
(p->Pptr ? p->Pptr->Sname : ""),
p->Poffset);
else
fprintf(f, "> PCONST R=%o, Wptr=[%s+%o]", p->Preg,
(p->Pptr ? p->Pptr->Sname : ""),
p->Poffset);
break;
case PTA_RCONST: /* Simple integer in pvalue */
fprintf(f, "> RCONST R=%o, Constant=%o", p->Preg, p->Pvalue);
break;
case PTA_FCONST: /* [single-prec float] */
fprintf(f, "> FCONST R=%o, Fltcon=%g", p->Preg, p->Pfloat);
break;
case PTA_DCONST: /* [double-prec float] */
fprintf(f, "> DCONST R=%o, Dblcon=%g", p->Preg, p->Pdouble);
break;
case PTA_DCONST1: /* [1st wd of double float] */
fprintf(f, "> DCONST1 R=%o, 1st wd of dblcon=%g", p->Preg, p->Pdouble);
break;
case PTA_DCONST2: /* [2nd wd of double float] */
fprintf(f, "> DCONST2 R=%o, 2nd wd of dblcon=%g", p->Preg, p->Pdouble);
break;
default:
fprintf(f, "Illegal ADRMODE value = %o", i);
}
fprintf(f, "\n");
}
/* More debug stuff. Pcode buffer compare, to show what's changed. */
static int cmpcnt = 0; /* Count of times compare done */
static PCODE *oldcodes = NULL;
static int omaxcode = 0, omincode = 0;
static void
shocum()
{
fprintf(fpho, "----------- Update %3d -----------------\n", cmpcnt++);
shocmp(fpho);
fprintf(fpho, "----------------------------------------\n");
}
/* SHOCMP - Output a buffer comparison */
static void
shocmp(f)
FILE *f;
{
PCODE *p, *q;
int i, lim;
if (oldcodes == NULL) /* Ensure old buffer copy exists */
if (!(oldcodes = (PCODE *)calloc(sizeof(codes), 1))) {
error(EOUTMEM);
return;
}
/* First check for new code prior to last stuff */
if (mincode < omincode) {
fprintf(f," NEW---- stuff prior to start of last check:\n");
for (i = mincode; i < omincode; ++i) {
fprintf(f, " NEW ");
shopcod(f, &codes[i&(MAXCODE-1)], i&(MAXCODE-1));
}
}
/* Then check for old code prior to current new start */
else if (omincode < mincode) {
fprintf(f," OLD---- stuff flushed from start of current code:\n");
for (i = omincode; i < mincode; ++i) {
fprintf(f, " OLD ");
shopcod(f, &oldcodes[i&(MAXCODE-1)], i&(MAXCODE-1));
}
}
/* Now compare stuff that's in both buffers */
lim = (maxcode < omaxcode) ? maxcode : omaxcode; /* Find smallest */
for (i = mincode; i < lim; ++i) {
p = &codes[i&(MAXCODE-1)];
q = &oldcodes[i&(MAXCODE-1)];
if (memcmp((char *)p, (char *)q, sizeof(PCODE)) == 0)
continue; /* Compared OK, keep going */
fprintf(f, " ----Changed\n OLD ");
shopcod(f, q, i&(MAXCODE-1));
fprintf(f, " ----to\n NEW ");
shopcod(f, p, i&(MAXCODE-1));
fprintf(f, " -----------\n");
}
/* Now check for new code added after last stuff */
if (maxcode > omaxcode) {
fprintf(f," ADD---- New stuff:\n");
for (i = omaxcode; i < maxcode; ++i) {
fprintf(f, " ADD ");
shopcod(f, &codes[i&(MAXCODE-1)], i&(MAXCODE-1));
}
}
/* Then check for old code still existing at end */
else if (maxcode < omaxcode) {
fprintf(f," OLD---- stuff flushed from end:\n");
for (i = maxcode; i < omaxcode; ++i) {
fprintf(f, " OLD ");
shopcod(f, &oldcodes[i&(MAXCODE-1)], i&(MAXCODE-1));
}
}
/* Now update our copy in preparation for next check */
memcpy((char *)oldcodes, (char *)codes, sizeof(codes));
omincode = mincode;
omaxcode = maxcode;
}
/* Various auxiliaries for dealing with pseudo-code */
/* NEWCODE() - Get a new pseudo-code record.
** Sets "previous" to the returned pointer, for global access.
*/
#define OVERINC 20 /* Number of ops to skip on overflow */
PCODE *
newcode()
{
int i;
previous = &codes[maxcode++ & (MAXCODE - 1)]; /* new previous */
if (maxcode >= mincode + MAXCODE - 1) /* overflow? */
for (i = 0; i < OVERINC; i++) /* yes, bump */
realcode(mincode++);
return previous;
}
/* BEFORE(p) - Return live instruction preceding this one.
** AFTER(p) - Return live instruction succeeding this one.
*/
PCODE *
before(p)
PCODE *p;
{
PCODE *b;
if (p == NULL) return NULL; /* make sure we have a real pseudo */
b = &codes[mincode&(MAXCODE-1)];
while (1) {
if (p == b) return NULL; /* start of buffer, can't back up */
--p; /* back before here */
if (p < &codes[0]) p = &codes[MAXCODE-1]; /* wrap in circular buffer */
if (p->Pop != P_NOP) return p; /* got a real op, return with it */
}
}
PCODE *
after(p)
PCODE *p;
{
PCODE *b = &codes[maxcode&(MAXCODE-1)];
if (p == NULL) return NULL; /* make sure we have a real pseudo */
while (1) {
if (++p > &codes[MAXCODE-1]) p = &codes[0]; /* wrap */
if (p == b) return NULL; /* end of buffer, no more code */
if (p->Pop != P_NOP) return p; /* got a real op, return with it */
}
}
/* SWAPPSEUDO(a,b) - swap two pseudo code locations
*/
swappseudo(a,b)
PCODE *a, *b;
{
PCODE temp;
temp = *b; /* Copy the structure to temp place */
*b = *a;
*a = temp;
}
/* FIXPREV() - Make sure "previous" points to something.
**
** This should be called after a pseudo-code which might be the last
** in the buffer is P_NOPed out. It sets previous to the new last
** instruction in the peephole buffer.
**
** Someday this might also change maxcode to save buffer space.
*/
void
fixprev()
{
if (previous != NULL && previous->Pop == P_NOP) {
previous = before (previous);
--maxcode; /* We know at least one flushed, but */
/* not sure how far back. 1 is better than nothing. */
}
}
/* FLSPOP(p) - Flush pseudo-code instruction (make it a NOP)
** FLSPREV() - Flush instruction that "previous" points to.
*/
void
flspop(p)
PCODE *p;
{
if (p) p->Pop = P_NOP;
if (p == previous)
fixprev();
}
static void
flsprev()
{ flspop(previous);
}
/* FLUSHCODE() - Flush peephole buffer (emit everything)
*/
void
flushcode()
{
if (mincode < maxcode) {
do realcode(mincode++);
while (mincode < maxcode);
if (debpho) {
fprintf(fpho,"FLUSHCODE:\n");
shocum(); /* Show stuff forced out. */
}
}
previous = NULL;
}
/*
** Register to register codes.
**
** Generates op r1,r2 for r1 and r2 both registers.
** CODE0 releases register r2 for future reassignment (although later
** peephole optimizations might notice that it hasn't been changed yet
** and re-use whatever value it contained).
**
** CODEK0 does NOT release register r2. The assignment operators need to
** keep around two registers sometimes.
*/
static void code00();
static void codrrx();
static int rrpre1(), rrpre2();
static void rrpre3(), rrpopt(), rrpop2();
static PCODE *chkmref(), *chkref();
void
codek0(op, r1, r2) /* KEEP the second register!! */
VREG *r1, *r2;
{
VREG *r3;
int s;
s = realreg(r3 = getreg());
release(r3);
code00(P_SETM, s, realreg(r2)); /* Use this to avoid losing r2 */
code00(op, realreg(r1), s);
if (debpho) shocum();
}
void
code0(op, r1, r2)
VREG *r1, *r2;
{
int s = realreg(r2);
if (r1 != r2) release(r2); /* flush operand for later */
code00(op, realreg(r1), s);
if (debpho) shocum();
}
static void
code00(op, r, s)
int r, s;
{
PCODE *p, *q, *prev;
if (debpho) {
shohdr();
fprintf(fpho,"CODE0: %o=%s %o,%o\n", op, popostr[op&POF_OPCODE], r, s);
}
/* Simple pre-optimization.
*/
s = ufcreg (s); /* flush failed changereg for 2nd AC */
if ((op & POF_OPCODE) == P_CAM) /* and other if comparison */
r = ufcreg (r);
/* Now just add the instruction. */
prev = previous; /* Remember previous, if any */
p = newcode();
p->Ptype = PTA_REGIS;
p->Pop = op;
p->Preg = r;
p->Pr2 = s;
if (!optobj) { /* If not optimizing, return now. */
if (debpho) shocum();
return;
}
/* Everything else is optimization hacks */
/* Try to avoid storing a MOVE-type op by going back through
** the buffer and changing code so that the operand register (s)
** is already the destination (r).
** Neither pushneg nor pnegreg creates or kills any instructions,
** so pointers remain safe.
*/
switch (op) {
case P_SETM: /* Special code to avoid optimizer! */
return; /* Otherwise S will get re-used. */
case P_MOVM: /* If case hash, */
rrpop2(p); /* just do post-checks */
return;
case P_MOVN: /* fold out P_MOVN */
if (r == s && pnegreg(s, prev)) {
/* Try to use other instrs */
flsprev(); /* Win, don't need MOVN at all */
return;
}
if (pushneg(s, prev)) {
p->Pop = P_MOVE; /* Value negated, change op to MOVE */
} /* and drop thru to handle MOVE */
else break;
case P_MOVE:
if (changereg (r, s, prev)) {
flsprev(); /* Won, can flush instr we added */
return;
}
break;
case P_DMOVE:
if (r == s) { /* Changereg doesn't like doubles, */
flsprev(); /* so this is the best we can do. */
return;
}
break;
}
codrrx(prev, p); /* Apply more optimizations. */
}
/* CODRRX - Auxiliary for CODE0.
** Basically intended to help make sense of the gigantic switch
** statement that previously existed.
** prev - instruction farther back in peephole buffer, which we are
** looking at.
** np - instruction we are trying to optimize (normally what was
** just added; an OP R,S instr).
*/
static void
codrrx(prev, np)
PCODE *prev, *np;
{
PCODE *q;
/* If have an unskipped previous instruction to look at,
** try to fold our newly added instr into it.
*/
if (prev != NULL && !prevskips(prev)) {
if (prev->Preg != np->Pr2
&& rrpre1(prev, np)) /* Prev instr R != new S */
return; /* If won, just return. */
if ((q = findrset(prev, np->Pr2))
&& rrpre2(q, np)) /* Prev instr R == new S */
return; /* If won, just return */
}
rrpop2(np); /* Try standard optimizations */
}
/* RRPRE1 - Auxiliary for CODE0.
** Checks previous instruction for optimization with the one we're
** currently adding. The constraints for coming here are that:
** P points to a previous instr, which is not skipped,
** such that its R (register field) is NOT the same as the S
** of the new instruction we are adding.
** NP points to the newly added instruction, which is always a
** register-register op.
*/
static int
rrpre1(p, np)
PCODE *p, *np;
{
PCODE *q;
int r = np->Preg;
int s = np->Pr2;
/* Check opcode of NEW instruction.
** Breaking out of the switch statement simply returns failure.
*/
switch (np->Pop & POF_OPCODE) {
/* If new instruction is going to crunch its Preg register, do the
** following checking.
*/
case P_ADD:
case P_IMUL:
case P_IOR:
case P_AND:
case P_XOR:
case P_FADR:
case P_FMPR:
#if 1 /* New stuff, doesn't quite work yet. */
case P_CAM:
/* If instruction is commutative, then we can try swapping the
** AC and MEM operands and seeing if any optimization results.
*/
if (s == R_SP) break; /* Never mess with stack reg! */
if (q = findrset(before(np), np->Preg)) {
switch (q->Pop) { /* Does that instr */
case P_SETZ: case P_SETO: /* set R in simple way? */
case P_MOVE: case P_MOVN:
break;
default: /* No, just give up. */
return 0;
}
if (q->Ptype == PTV_IINDEXED) /* Ignore if imm addr op */
break;
np->Preg = s; /* Reverse order of AC,E in op */
np->Pr2 = r;
if ((np->Pop&POF_OPCODE) == P_CAM) {
np->Pop = swapop(np->Pop); /* Invert the skip test */
if (rrpre2(q, np))
return 1;
np->Pop = swapop(np->Pop); /* Restore original test */
}
else if (rrpre2(q, np)) { /* Re-check optimization now */
code0(P_MOVE, r, s); /* Won, put back in right reg */
return 1;
}
np->Preg = r; /* Failed, restore ordering. */
np->Pr2 = s;
return 0; /* Return failure so rrpre2 called */
}
break;
#else /* Old version of preceding stuff */
/* Non-commutative ops */
case P_SUB:
case P_FSBR:
case P_FDVR:
/* If previous instruction is one that sets R in a simple way,
** and new instruction is commutative, we swap R and S in new instr
** and try to optimize that.
*/
switch (p->Pop) { /* Does prev instr */
case P_SETZ: case P_SETO: /* set R in simple way? */
case P_MOVE: case P_MOVN:
if (p->Preg == r) {
if (p->Ptype == PTV_IINDEXED)
break; /* If complicated addr, forget it */
if (np->Pop == P_SUB
|| np->Pop == P_FSBR
|| np->Pop == P_FDVR)
break; /* Op not commutative, forget it */
np->Preg = s; /* Reverse order of AC,E in op */
np->Pr2 = r;
codrrx(before(np), np); /* Re-check optimization now */
code0(P_MOVE, r, s); /* and put back in right reg */
return 1;
}
/* Doesn't affect R, drop thru to see if OK to keep looking. */
/* See whether OK to keep looking back or not.
** At the moment we just check a few kinds of ops, could probably
** do better than this.
*/
case P_SUB: case P_ADD: case P_IMUL:
case P_IOR: case P_AND: case P_XOR:
case P_FADR: case P_FSBR: case P_FMPR: case P_FDVR:
if (rmodreg(p, r) /* If prev instr changes a reg */
|| rmodreg(p, s))
break; /* then stop now. */
/* Drop thru */
/* Stack change is OK to keep looking back over. */
case P_ADJSP:
codrrx(before(p), np); /* Continue looking back */
return 1;
} /* end switch (p->Pop) */
break; /* Give up, add instr */
case P_CAM:
if (p->Preg != r || p->Pop != P_MOVE)
break; /* Give up */
/* Convert MOVE R,x /.../ CAMx R,S
** into MOVE R,x /.../ CAMz S,R
** and then invoke further optimization of RRPRE2 since
** previous instr's R is now == S.
*/
np->Preg = s; /* Switch registers of the CAM */
np->Pr2 = r;
np->Pop = swapop(np->Pop); /* and invert the skip test */
break; /* Then fail, so RRPRE2 gets invoked. */
#endif
}
return 0; /* Failed to do any optimization */
}
/* RRPRE2 - (another) Auxiliary for CODE0.
** Checks previous instruction for optimization with the one we're
** currently adding. The constraints for coming here are that:
** P points to a previous instr, which is not skipped,
** such that its R (register field) is the SAME as the S
** of the new instruction we are adding.
** NP points to the newly added instruction, which is an OP R,S.
** (register-register op)
** Note that S is NOT referenced by anything between P and NP,
** which makes various things safe.
*/
static int
rrpre2(p, np)
PCODE *p, *np; /* An existing instruction being examined */
{
int op = np->Pop; /* OP R,S of new instruction we want to add */
int r = np->Preg;
int s = np->Pr2;
PCODE *q;
/* Check opcode of PREVIOUS instr.
** Breaking out of the switch statement simply leaves new instr alone
** and returns failure.
*/
switch (p->Pop & (POF_OPCODE | POF_BOTH)) {
case P_IMUL:
{ PCODE *b, *bb;
if (p != before(np)) break; /* For now */
if (op != P_SUB || (q = before (p)) == NULL || q->Pop != P_IDIV ||
q->Preg != p->Preg || !sameaddr (p, q, 0) ||
(b = before (q)) == NULL || b->Pop != P_MOVE ||
b->Preg != p->Preg) break;
if (b->Ptype == PTA_REGIS && b->Pr2 == r) bb = NULL;
else if ((bb = before (b)) == NULL || bb->Preg != r ||
bb->Pop != P_MOVE || prevskips (bb) ||
!sameaddr (b, bb, 0)) break;
/*
** fold: MOVE R,x
** MOVE S,x
** IDIV S,y
** IMUL S,y
** SUB R,S
**
** into: MOVE S,x
** IDIV S,y
** MOVE R,S+1
**
** for ignorant Pascal programmers.
*/
if (bb != NULL) bb->Pop = P_NOP; /* drop first move */
p->Pop = P_NOP; /* drop P_IMUL */
np->Pop = P_NOP; /* Drop new instr */
fixprev(); /* point to end of peephole buffer */
code0(P_MOVE, r, s + 1); /* put result in right reg */
return 1;
}
case P_DMOVN: /* similar to P_MOVN below */
switch (op) {
case P_DMOVE: /* move P_MOVN over for optimization */
p->Pop = P_DMOVE; op = P_DMOVN; break;
case P_DMOVN: /* cancel double P_MOVN */
p->Pop = P_DMOVE; op = P_DMOVE; break;
case P_DFAD: /* R + -X is same as R - X */
p->Pop = P_DMOVE; op = P_DFSB; break;
case P_DFSB: /* R - -X is same as R + X */
p->Pop = P_DMOVE; op = P_DFAD; break;
default:
return 0; /* Give up, failed to add instr */
}
/* Then drop through to following case */
case P_DMOVE:
switch (op) {
case P_DFAD: case P_DFSB: case P_DFDV: case P_DFMP:
case P_DMOVE: case P_DMOVN:
/* Optimize DMOVE S,x /.../ Dop R,S
** into Dop R,x
*/
np->Pop = op;
rrpre3(p, np);
return 1;
/* Try to fold DMOVE R,M / PUSH x,R / PUSH x,R+1
** into PUSH x,M / PUSH x,M+1
** We come here when the current instr is DMOVE and we are adding
** a PUSH.
*/
case P_PUSH:
if (p != before(np)) break; /* For now */
/* Check out addressing mode, and forget it unless
** it's a plain vanilla REGIS, MINDEXED, or DCONST.
** Indirection, immediateness, or skippedness all cause failure.
*/
switch (p->Ptype) {
case PTA_REGIS:
case PTA_MINDEXED:
case PTA_DCONST:
break;
default:
return 0; /* Give up, no optimization done */
}
/* First turn DMOVE R,M / PUSH P,R
** into MOVE R+1,M+1 / PUSH P,M
*/
p->Pop = P_MOVE; /* Change the DMOVE R,M */
p->Preg++; /* into MOVE R+1,M */
switch (p->Ptype) { /* Now fix up memory operand */
case PTA_REGIS:
p->Pr2++; /* MOVE R+1,R2+1 */
/* PUSH P,R2 */
break;
case PTA_MINDEXED:
flspop(np); /* Flush new instr */
code7(P_PUSH, r, p->Pptr, /* MOVE R+1,M+1 */
p->Poffset++, p->Pindex); /* PUSH P,M */
np = previous;
break;
case PTA_DCONST:
p->Ptype = PTA_DCONST2; /* MOVE R+1,1+[const] */
np->Ptype = PTA_DCONST1; /* PUSH R,[const] */
np->Pdouble = p->Pdouble;
break;
}
/* Now try to rearrange the MOVE / PUSH into PUSH / MOVE
** if we still know where things are (not always true).
** np should point to the PUSH.
*/
if (np->Pop != P_PUSH) return 1; /* If not, forget it */
if ((p = before(np)) /* See if prev instr is */
&& (p->Pop == P_MOVE)) { /* still MOVE */
/* Yep, swap 'em */
if ((p->Ptype&PTF_ADRMODE)==PTA_MINDEXED
&& p->Pindex == R_SP)
p->Poffset--;
swappseudo(p, np); /* into PUSH / MOVE */
}
return 1;
}
break;
case P_IOR:
case P_ADJBP:
if (op == P_LDB || op == P_DPB) { /* If one-time use of BP, */
if (localbyte(p, np)) /* try to make it local-fmt */
return 1; /* Won, folded. */
}
#if 0 /* Not needed anymore */
if (p->Pop != P_ADJBP && p->Pop != P_IOR) {
/* If changed by localbyte, */
codrrx(previous, op, r, s); /* Restart search backwards */
return 1;
}
#endif
break;
case P_SETZ:
switch (op) {
case P_MOVE: /* fold: SETZ S, */
case P_FMPR: /* ... */
case P_IMUL: /* MOVE/etc R,S */
case P_MOVN: /* into: SETZ R, */
case P_FLTR:
np->Pop = P_SETZ; /* Replace this op with a SETZ R, */
np->Ptype = PTA_ONEREG;
flspop(p); /* Flush the old SETZ */
return 1;
case P_ADD: /* fold: SETZ S, */
case P_FADR: /* ... */
case P_SUB: /* ADD R,S */
case P_FSBR: /* into: null */
flspop(np); /* Flush the new op */
flspop(p); /* and flush the SETZ */
return 1;
}
case P_SETO: /* fall in from P_SETZ above */
/* Change SETZ/SETO S, to MOVNI S,0/1 */
p->Pvalue = (p->Pop == P_SETO ? 1 : 0);
p->Pop = P_MOVN;
p->Ptype = PTV_IMMED; /* then drop through */
case P_MOVN:
/* invert MOVN(*) to MOVE(*) for following optimization */
switch(op & POF_OPCODE) {
case P_MOVE:
p->Pop = P_MOVE; /* move P_MOVN over for optimization */
np->Pop = P_MOVN;
break;
case P_MOVN:
p->Pop = P_MOVE; /* cancel double P_MOVN */
np->Pop = P_MOVE;
if (changereg (r, s, p)) {
flspop(np); /* Flush pointless MOVE */
return 1;
}
break;
case P_ADD: /* R + -X is same as R - X */
p->Pop = P_MOVE;
np->Pop = P_SUB;
break;
case P_SUB: /* R - -X is same as R + X */
p->Pop = P_MOVE;
np->Pop = P_ADD;
break;
case P_FADR: /* R + -X is same as R - X */
p->Pop = P_MOVE;
np->Pop = P_FSBR;
break;
case P_FSBR: /* R - -X is same as R + X */
p->Pop = P_MOVE;
np->Pop = P_FADR;
break;
case P_CAM: case P_IMUL: case P_FMPR: case P_FDVR:
if (p->Ptype != PTV_IMMED
&& (q = before(p)) != NULL
&& q->Preg == r
&& !prevskips (q))
switch (q->Pop) {
case P_MOVE: /* a <= -b is same as -a >= b */
q->Pop = P_MOVN;
p->Pop = P_MOVE;
np->Pop = swapop(np->Pop);
codrrx(p, np); /* Continue looking back */
return 1;
case P_MOVN: /* -a <= -b is same as a >= b */
q->Pop = P_MOVE;
p->Pop = P_MOVE;
np->Pop = swapop(np->Pop);
codrrx(p, np); /* Continue looking back */
return 1;
}
default:
if (p->Ptype == PTV_IMMED) {
p->Pop = P_MOVE; /* unknown const case, make P_MOVE */
p->Pvalue = - p->Pvalue; /* with negated value */
} else {
return 0; /* Give up, no optimization done */
}
} /* Drop through to following case */
case P_MOVE:
rrpre3(p, np); /* Always takes care of everything */
return 1;
case P_ADD:
case P_SUB:
/*
** fold: ADD/SUB S,x
** ...
** ADD/SUB R,S
**
** into: ADD/SUB R,x
** ...
** ADD/SUB R,S
**
** and keep looking back for further optimization.
*/
/* Ensure that new instr is ADD or SUB before wasting more time */
if (op != P_ADD && op != P_SUB)
break;
/* Make sure the old ADD/SUB doesn't use its own reg as index */
if (rinaddr(p, p->Preg))
break;
/* See whether new instr's reg is otherwise referenced.
** It is OK to skip over references of the form ADD/SUB R,M as
** the result doesn't depend on the order of the instrs, and this
** allows us to convert things like (a - (b+c+d)) into (a-b-c-d).
*/
for (q = before(np); q = chkref(p, q, r); q = before(q)) {
/* Found a reference, see if it's OK to pass by. */
if ((q->Pop == P_ADD || q->Pop == P_SUB) /* ADD or SUB? */
&& r == q->Preg && !rinaddr(q, r)) /* R ref reg-only? */
continue; /* Win, skip over */
return 0; /* Failed, no optimization. */
}
if (op == P_SUB) /* If new instr is SUB, */
p->Pop ^= (P_ADD ^ P_SUB); /* invert sense of old instr */
p->Preg = r; /* Make ADD/SUB S,x be ADD/SUB R,x */
codrrx(before(p), np); /* Continue optimization if can */
return 1;
case P_SETZ+POF_BOTH: case P_SETO+POF_BOTH:
if (p->Ptype == PTA_REGIS
&& (op == P_DMOVE || op == P_DMOVN)
&& p->Preg == s && p->Pr2 == s + 1) {
/*
** fold: SETZB/SETOB S,S+1
** ...
** DMOVE R,S
**
** into: SETZB R,R+1
*/
np->Pop = p->Pop; /* Copy the SETZB/SETOB */
np->Pr2 = np->Preg + 1;
flspop(p); /* Flush the SETZB/SETOB */
return 1;
}
} /* end switch (p->Pop&(POF_OPCODE|POF_BOTH)) */
return 0; /* No optimization done, let caller handle it. */
}
/* RRPRE3 - (yet another) Auxiliary for RRPRE2 (auxiliary for CODE00).
** Handles case where previous instruction was MOVE S,x
** and new instr is OP R,S.
** fold: p-> MOVE/MOVEI/DMOVE S,x
** ...
** OP R,S
**
** into: OP R,x
**
** If there are instructions in between (i.e. "..." contains something) then
** we need to be careful that:
** (1) S is NOT otherwise referenced between the MOVE and the OP.
** (2) OP is not a skip, and R is NOT referenced in "..."
** If so, then OK to change the MOVE to OP R,X.
** Otherwise, (3) X doesn't use anything that "..." changes.
** If so, we can flush the MOVE and add the OP R,X.
** Otherwise give up.
**
** Rule (1) is satisfied by findrset().
*/
static void
rrpre3(p, np)
PCODE *p, *np;
{
PCODE *q, *rp;
int stkoff;
/* don't make an XPUSHI - foldstack works better without it */
if (p->Ptype == PTV_IINDEXED && np->Pop == P_PUSH) {
rrpop2(np); /* Just do simple post-ops */
return;
}
/* If there's nothing in between, then no need to worry about rules.
** That case is tested on the first pass of the following loop.
** Loop checks out possibility of replacing the MOVE.
** We win if R is not referenced or used by anything in between.
*/
q = before(np);
if ( p == q /* Always OK if no "..." in between */
|| (!isskip(np->Pop) /* Otherwise must not be skip */
&& !chkref(p, q, np->Preg))) { /* and "..." must not reference R. */
p->Pop = np->Pop; /* Win!! Change MOVE S,X */
p->Preg = np->Preg; /* to OP R,X */
flspop(np); /* Flush new instr */
rrpopt(p); /* Do more checks on result! */
return;
}
/* Checking for R usage didn't work out.
** Now apply painful check of X by going forwards from
** the MOVE, checking each instr to make sure it cannot reference
** X or use a register that X does.
*/
if (chkmref(p, np, &stkoff) == NULL) {
/* WON! Zap the MOVE and turn new op into OP R,X */
int op = np->Pop, r = np->Preg; /* Save OP and R */
*np = *p; /* Copy MOVE into added instr */
p->Pop = P_NOP; /* Then zap the MOVE */
np->Pop = op; /* Change MOVE S,X */
np->Preg = r; /* to OP R,X */
if (stkoff) /* If stack indexed through and it changed, */
np->Poffset -= stkoff; /* adjust offset of instruction. */
rrpopt(np); /* Do post-optimization checks now! */
return;
}
rrpop2(np); /* Failed, apply standard post-opts. */
}
/* CHKREF(p, q, reg) - Checks series of instrs to see if any reference
** the specified register.
** Searches backwards from q (INCLUSIVE) to p (EXCLUSIVE).
** Returns non-NULL pointer to most recent reference found.
** Returns NULL if no reference seen.
*/
static PCODE *
chkref(begp, q, r)
PCODE *begp, *q;
int r;
{
for (; q && begp != q; q = before(q)) {
if (rinreg(q, r) || rinaddr(q, r))
return q; /* Quit loop if find a reference */
}
return NULL;
}
/* CHKMREF - Check an instr sequence for anything affecting a mem ref.
** BEGP points to start (INCLUSIVE), the instr here defines X.
** ENDP points to end (EXCLUSIVE)
** Returns pointer to offending instr if any ref found.
**
** Applies painful check of X (for OP R,X) by going forwards from
** the begp (inclusive), checking each instr to make sure it cannot reference
** X or use a register that X does, since we want to move the X reference
** from the instr at begp to the instr at endp.
** This involves three distinct checks:
** (1) If the original instr at begp modifies memory, then this
** is considered a conflicting reference and we fail, since
** the instr at endp probably depends on the new value.
** (2) If X uses a register, that register must not be changed
** by an intervening instruction!
** (3) If an intervening instruction references the same place
** as X (or even threatens to do so), then it must not change
** memory.
** Must track stack offset both in order to properly check for sameaddr(),
** and to correct the X if it uses the stack (and something in "..."
** changed stack ptr).
**
** If X depends on stack pointer value, the returned
** offset will be nonzero and X needs it added to its Poffset if it is
** to be used in the instruction at ENDP.
** If at any point the stack offset changes in a way that means X
** would become non-existent (not on the stack, i.e. a positive stack
** offset) then the routine fails immediately.
*/
static PCODE *
chkmref(begp, endp, aoff)
PCODE *begp, *endp;
int *aoff;
{
PCODE *q;
int ioff;
int stkoff = 0;
int xreg = -1; /* Default assumes X uses no reg */
*aoff = 0;
if ((begp->Pop&POF_BOTH) || (popflg[begp->Pop&POF_OPCODE]&PF_MEMCHG))
return begp; /* Start instr changes mem! Fail. */
switch (begp->Ptype&PTF_ADRMODE) {
case PTA_BYTEPOINT:
case PTA_MINDEXED:
if (begp->Pindex) /* If nonzero index reg, remember it */
xreg = begp->Pindex;
if (xreg != R_SP) /* Unless stack ptr, forget offset */
aoff = NULL;
break;
case PTA_REGIS:
xreg = begp->Pr2; /* Then drop thru to ignore offset */
default:
aoff = NULL;
break;
}
for (q = after(begp); q; q = after(q)) {
if (q == endp) {
if (aoff) *aoff = stkoff;
return NULL; /* Won, return 0 (no reference) */
}
/* Not yet done with loop, check out this instr */
if (sameaddr(begp, q, stkoff) || alias(begp, q, stkoff)) {
if ((q->Pop&POF_BOTH) || (popflg[q->Pop&POF_OPCODE]&PF_MEMCHG))
break; /* P and Q may refer to same place, and the instr */
} /* changes memory, so must fail. */
/* Account for stack changes.
** A PUSH, POP, or ADJSP of the stack can be understood and the
** rinreg test skipped if we are using the stack ptr as index reg
** (otherwise rinreg would flunk the instr).
*/
ioff = 0;
switch(q->Pop&POF_OPCODE) {
case P_PUSH:
if (q->Preg == R_SP) ioff = 1;
break;
case P_POP:
if (q->Preg == R_SP) ioff = -1;
break;
case P_ADJSP:
if (q->Preg == R_SP) ioff = q->Pvalue;
break;
}
stkoff += ioff;
if (ioff && aoff) { /* Stack change, and using ptr as index reg */
if ((begp->Poffset - stkoff) > 0)
break; /* Cell no longer protected by stack ptr */
continue; /* OK, can skip rinreg test */
} else if (xreg >= 0 && rmodreg(q, xreg))
break; /* Modifies register that X needs */
}
if (aoff) *aoff = stkoff;
return q;
}
/* RRPOPT - Post-optimization after adding reg-reg instruction.
** We've just turned the sequence
** MOVE S,x into: OP R,x
** OP R,S
** and want to do further optimization on the new op/address combination
** resulting from that fold.
** P points to the OP R,x instruction.
*/
static void
rrpopt(p)
PCODE *p;
{
PCODE *q;
int op;
/* P_CAML for an immediate type needs to become P_CAIL... */
if ((op = immedop(p->Pop)) && (p->Ptype & PTF_IMM)) {
p->Pop = op; /* Change op to immediate type, and make */
p->Ptype &= ~ PTF_IMM; /* operand PTA_RCONST instead of PTV_IMMED */
foldskip(p, 1); /* Fix up P_CAI */
return;
}
q = before(p); /* look back before munged move. May be NULL! */
/* Big post-optimization switch: see what the added op was.
** Breaking out just returns, since instr has already been added.
*/
switch (p->Pop & POF_OPCODE) {
case P_PUSH:
code8(P_ADJSP, R_SP, 0); /* try adjustment */
break; /* return */
case P_SKIP:
if (p->Pop == P_SKIP+POF_ISSKIP+POS_SKPE
&& p->Ptype == PTV_IINDEXED)
/* Fold: P_SKIPEI R,addr
** Into: XMOVEI R,addr
** assuming that the SKIP is part of a (char *) cast
** conversion of an immediate address value.
*/
p->Pop = P_MOVE;
break; /* return */
case P_FLTR:
if (p->Ptype != PTV_IMMED)
break; /* Return, not immediate operand */
p->Pop = P_MOVE; /* fold: FLTRI R,x */
p->Ptype = PTA_FCONST; /* into: MOVSI R,(xE0) */
/* This only works if target machine is same as source machine! */
p->Pfloat = (float) p->Pvalue;
break; /* return */
case P_IMUL:
if (p->Ptype != PTV_IMMED) return;
if (p->Pvalue == 1) {
p->Pop = P_NOP; /* drop IMULI R,1 */
fixprev(); /* Fix up end of peephole buffer */
break; /* then return */
}
if (q && q->Ptype == PTV_IMMED /* !prevskips */
&& q->Preg == p->Preg) switch(q->Pop) {
case P_SUB: case P_ADD:
/*
** fold: ADDI/SUBI R,n
** IMULI R,m
**
** into: IMULI R,m
** ADDI/SUBI R,m*n
*/
q->Pvalue *= p->Pvalue; /* premultiply constant */
swappseudo (p, q); /* put add after multiply */
p = q; /* look at multiply for below */
q = before(p); /* and before in case another mult */
if (q == NULL /* Check whether safe to drop in */
|| q->Pop != P_IMUL
|| q->Ptype != PTV_IMMED
|| q->Preg != p->Preg)
break; /* No, return now. */
/* Drop through to next case */
case P_IMUL:
/*
** fold: IMULI R,n
** IMULI R,m
**
** into: IMULI R,n*m
*/
q->Pvalue *= p->Pvalue; /* multiply both together */
p->Pop = P_NOP; /* only keep earlier one */
fixprev(); /* Fix up end of buffer */
break; /* Then return */
case P_MOVN: case P_MOVE:
/*
** fold: MOVEI/MOVNI R,n
** IMULI R,m
**
** into: MOVEI/MOVNI R,m*n
*/
q->Pvalue *= p->Pvalue; /* mult const by factor */
p->Pop = P_NOP; /* flush folded multiply */
fixprev(); /* Fix up end of buffer */
break; /* then return */
}
break;
case P_LDB:
case P_DPB:
if (p->Ptype == PTA_BYTEPOINT)
switch (p->Pbsize) {
/*
** fold: P_LDB R,[2200,,x]
** into: P_HRRZ R,x
*/
case 0222200: /* left half? */
p->Ptype = PTA_MINDEXED;
/* if (p->Pindex & 020) p->Ptype |= PTF_IND; */
p->Pop = (p->Pop == P_LDB)? P_HLRZ : P_HRLM;
break;
case 02200: /* right half? */
p->Ptype = PTA_MINDEXED;
/* if (p->Pindex & 020) p->Ptype |= PTF_IND; */
p->Pop = (p->Pop == P_LDB)? P_HRRZ : P_HRRM;
}
/* Then look for IBP to fold into ILDB or IDPB. */
foldmove(p);
break; /* Done, return */
case P_ADJBP:
foldbyte(p); /* fix up ADJBP instruction */
break; /* return */
case P_SUB:
if (p->Ptype == PTV_IMMED
&& q != NULL
&& q->Preg == p->Preg
&& (q->Ptype == PTV_IMMED || q->Ptype == PTV_IINDEXED))
switch (q->Pop) { /* check safe then switch */
case P_MOVE:
case P_ADD:
q->Poffset -= p->Poffset;
p->Pop = P_NOP; /* fold: ADDI/MOVEI R,n */
fixprev(); /* SUBI R,m */
foldplus(q); /* into: ADDI R,n-m */
return;
case P_SUB:
q->Poffset += p->Poffset;
p->Pop = P_NOP; /* fold: SUBI R,n */
fixprev(); /* SUBI R,m */
return; /* into: SUBI R,n+m */
}
/* fall through to foldplus() */
case P_ADD:
foldplus(p); /* do general optimization on add */
if (p != previous) /* Take care of possible ADDI+ADDI */
foldplus(previous); /* that sometimes results */
break; /* return */
case P_CAM:
if (q != NULL
&& q->Ptype == PTA_REGIS /* !prevskips */
&& q->Pop == P_MOVE
&& q->Preg == p->Preg) {
/*
** fold: P_MOVE R,S
** P_CAMx R,x
**
** into: P_CAMx S,x
*/
p->Preg = q->Pr2; /* flatten tested register */
q->Pop = P_NOP; /* flush useless move */
}
break; /* Return */
default:
rrpop2(p); /* Apply usual opts */
return;
} /* End of huge switch on newly-added op code */
}
/* RRPOP2 - Auxiliary for CODE0, does some optimizations on OP R,S.
*/
static void
rrpop2(p)
PCODE *p;
{
/* Unless it's a bad idea, check for addr being a constant. */
if (p->Pop != P_PUSH && p->Pop != P_MOVE) {
findconst(p); /* turn P_CAMN R,S into P_CAIN R,0 */
p = previous; /* Recover ptr to most recent instr */
}
switch (p->Pop & POF_OPCODE) {
case P_PUSH:
code8(P_ADJSP, R_SP, 0); /* hack up stack */
break;
case P_AND:
case P_IOR:
case P_XOR:
inskip(p); /* turn SKIPA/MOVE/IOR into TLOA/IOR */
break;
case P_CAI:
case P_CAM:
foldskip(p);
break;
case P_ADJBP:
foldbyte(p); /* fix up ADJBP instruction */
break;
case P_ADD:
foldplus(p); /* maybe addition can be fixed now */
break;
case P_MOVE:
case P_LDB:
case P_DPB:
foldmove(p); /* fix IBP/DPB, copy of reg-reg move */
break;
}
}
/*
** Immediate register constant codes.
** Generates opI r,s where s is a number (ptype PTV_IMMED).
*/
void
code1(op, r, s)
{
PCODE *p;
r = realreg(r);
if (debpho) {
shohdr();
fprintf(fpho,"CODE1: %o=%s+I %o,%o\n",
op, popostr[op&POF_OPCODE], r, s);
}
p = newcode();
p->Ptype = PTV_IMMED;
p->Pop = op;
p->Preg = r;
p->Poffset = s;
if (optobj) {
foldplus(p); /* now do post-optimizations */
foldmove(previous); /* "previous" instead of "p", maybe changed */
}
if (debpho) shocum();
}
/*
** Local byte pointer
**
** Generates op r,[bbbbii,,p+o] i.e. a local byte pointer with p/s in b.
** Used in optimization of string ops, and in generating struct bit fields.
*/
void
code2(op, reg, b, idx, sym, o)
VREG *reg, *idx;
SYMBOL *sym;
{
PCODE *p, *q;
int soff; /* For holding returned stack offset from chkmref */
int r = realreg(reg), i = realreg(idx);
if (debpho) {
shohdr();
fprintf(fpho,"CODE2: %o=%s %o,[%o,,%s+%o(%o)]\n",
op, popostr[op&POF_OPCODE], r, b,
(sym ? sym->Sname : ""),
o, i);
}
p = newcode(); /* Add the instruction */
p->Ptype = PTA_BYTEPOINT;
p->Pop = op;
p->Preg = r;
p->Pindex = i;
p->Pptr = sym;
p->Poffset = o;
p->Pbsize = b; /* Store P+S field here */
if (!optobj) { /* If not optimizing, return now. */
if (debpho) shocum();
return;
}
/* Apply local-format byte-pointer optimizations */
/* Look for a previous instruction that sets the index register */
if ((q = findrset(before(p), i))) /* If find a prev instr */
switch (q->Pop) { /* then examine it */
case P_ADD:
if (q->Ptype == PTV_IMMED) {
p->Poffset += q->Pvalue; /* this BP has an offset */
flspop(q); /* drop the ADDI */
}
break;
case P_SUB:
if (q->Ptype == PTV_IMMED) {
p->Poffset -= q->Pvalue; /* this BP has an offset */
flspop(q); /* drop the SUBI */
}
break;
case P_MOVE: /* MOVE or MOVEI */
if (sym != NULL) break; /* don't double up symbol */
if (chkmref(q, p, &soff)) /* Verify OK to steal addr */
break;
if (q->Ptype == PTA_MINDEXED) {
/* See if can use indirection */
if ( soff /* Cannot use offset */
|| p->Poffset != 0 /* of any kind */
|| op == P_ADJBP /* Cannot adj an indirect BP */
|| op == P_IBP /* Cannot bump it either */
|| op == P_ILDB
|| op == P_IDPB)
break;
p->Ptype |= PTF_IND; /* Indirect OK, set @ bit! */
} else if (q->Ptype != PTV_IINDEXED)
break;
p->Pptr = q->Pptr; /* new addr symbol */
p->Pindex = q->Pindex; /* index */
p->Poffset += q->Poffset - soff; /* and offset */
flspop(q); /* drop the move */
}
foldmove(p); /* Look for another like that */
if (debpho) shocum();
}
/*
** Address immediate -> register codes.
**
** Generates opI r,s with s a symbol (ptype PTV_IINDEXED). If left unoptimized
** this will be generated as P_XMOVEI 16,s / op r,16.
*/
void
code3(op, r, s)
SYMBOL *s;
{
PCODE *p;
r = realreg(r);
if (debpho) {
shohdr();
fprintf(fpho,"CODE3: %o=%s+I %o,%s\n", op, popostr[op&POF_OPCODE], r,
(s ? s->Sname : ""));
}
p = newcode();
p->Ptype = PTV_IINDEXED;
p->Pop = op;
p->Preg = r;
p->Pptr = s;
p->Poffset = 0;
p->Pindex = 0;
if (debpho) shocum();
}
/*
** Register to indexed register.
**
** Generates op reg,(idx) i.e. indexes through the second register.
** This is used after a gaddress() to get the contents of a variable,
** and also for assignment ops (like Q_ASGN = P_MOVEM). The index is released.
**
** CODEK4 is the same but doesn't release the index register.
**
** CODE4S takes an extra argument which it stuffs into the Pbsize field
** of the stored op. This is used as a special hack for P_SMOVE only,
** and the size is associated with the op rather than the operand.
*/
static void code40();
void
code4(op, reg, idx)
VREG *reg, *idx;
{
int r = realreg(reg), s = ufcreg(realreg(idx));
if (reg != idx) release(idx); /* will no longer need register */
code40(op, r, s, 0);
if (debpho) shocum();
}
void
codek4(op, reg, idx)
VREG *reg, *idx;
{
VREG *r3;
int r, s;
r = ufcreg(realreg(idx));
s = realreg(r3 = getreg());
release(r3);
code00(P_SETM, s, r); /* Use this to avoid losing r2 */
code40(op, realreg(reg), s, 0);
if (debpho) shocum();
}
void
code4s(op, reg, idx, keep, bsiz)
VREG *reg, *idx;
{
VREG *r3;
int r, s;
if (keep) {
r = ufcreg(realreg(idx));
s = realreg(r3 = getreg());
release(r3);
code00(P_SETM, s, r); /* Use this to avoid losing r2 */
r = realreg(reg);
} else {
r = realreg(reg);
s = ufcreg(realreg(idx));
if (reg != idx) release(idx); /* will no longer need register */
}
code40(op, r, s, bsiz);
if (debpho) shocum();
}
static void
code40(op, r, s, bsiz)
int r, s;
{
PCODE *p, *q, *b, *oldprev;
SYMBOL *ssymbol;
int ty, o, soffset;
if (debpho) {
shohdr();
fprintf(fpho,"CODE4: %o=%s %o,(%o) siz %o\n",
op, popostr[op&POF_OPCODE], r, s, bsiz);
}
/* First just add the instruction */
p = newcode();
p->Ptype = PTA_MINDEXED;
p->Pptr = NULL;
p->Pop = op;
p->Preg = r;
p->Poffset = 0;
p->Pindex = s;
p->Pbsize = bsiz;
if (!optobj) { /* If not optimizing, return now. */
if (debpho) shocum();
return;
}
/* Attempt optimizations by looking for an instruction that sets S
** (the index register). If found, this will be a single-word op
** that is not skipped over and thus is safe to NOP out.
*/
oldprev = before(p); /* Find old previous */
/* If have a single-word op setting S, check simple cases. */
if (q = findrset(oldprev, s)) switch (q->Ptype) {
case PTV_IMMED: /* Immediate RCONST */
switch (q->Pop) {
/* fold: MOVEI/MOVNI S,const
** ...
** OP R,(S)
** into:
** OP R,const (or -const)
*/
case P_MOVN:
q->Pvalue = - q->Pvalue;
case P_MOVE:
if (q == oldprev) { /* Can we re-use last instr? */
q->Pop = op; /* Yes! Change its op and r */
q->Ptype = PTA_RCONST; /* Take immediateness out */
q->Preg = r;
q->Pbsize = bsiz;
p = q; /* Say this is now current instr */
flsprev(); /* Then flush instr that was added */
} else { /* No, zap MOVEI */
p->Ptype = PTA_RCONST; /* Change our addr mode */
p->Pvalue = q->Pvalue; /* to imm constant */
q->Pop = P_NOP; /* Now can flush the MOVEI */
}
/* Special check here for LSH (possible bitfield hacking) */
if (p->Pop == P_LSH)
optlsh(p); /* Attempt to optimize LSH */
return;
/* fold: ADDI/SUBI S,offset
** ...
** OP R,(S)
** into:
** OP R,offset(S)
*/
case P_SUB:
q->Pvalue = - q->Pvalue;
case P_ADD:
p->Poffset = q->Pvalue; /* Set offset to added val */
q->Pop = P_NOP; /* Then drop the ADDI/SUBI */
q = before(q); /* Back up to previous good instr */
/* for the foldcse coming up. */
/* If instruction setting the S reg was a MOVE S,I
** then flush it, as we can use I directly.
*/
if ((b = findrset(q, s))
&& b->Ptype == PTA_REGIS
&& b->Pop == P_MOVE
&& b->Preg == s) {
s = b->Pr2; /* Change our index reg to I */
b->Pop = P_NOP; /* and drop needless move */
q = NULL; /* Start foldcse from oldprev */
}
break; /* Now break out to do foldcse and foldboth */
}
break;
case PTV_IINDEXED: /* If op S,<Immediate MINDEXED> */
switch (q->Pop) {
case P_MOVE:
/*
** fold: P_XMOVEI S,addr (Immediate MINDEXED)
** ...
** OP R,(S)
**
** into: OP R,addr
*/
if (q == oldprev) { /* Can we re-use last instr? */
q->Pop = op; /* Yes! Fix it up */
q->Ptype = PTA_MINDEXED;
q->Preg = r;
q->Pbsize = bsiz;
flsprev(); /* And flush what we added earlier */
} else { /* No, zap XMOVEI and use new loc */
p->Pptr = q->Pptr; /* Update our new address */
p->Pindex = q->Pindex;
p->Poffset = q->Poffset;
q->Pop = P_NOP; /* Zap the XMOVEI */
}
foldboth();
return;
case P_ADD: /* ADDI S,addr */
/*
** fold: ADDI S,addr(I)
** OP R,(S)
**
** into: MOVEI S,addr(S)
** ADD S,I
** OP R,(S)
**
** and optimize further...
**
** NOTE: only do this if ADDI is the first preceding instr
** (oldprev), because otherwise register I also needs to
** be checked for intermediate usage, and the "optimize
** further" routines aren't smart enough yet to go back
** far enough.
*/
if (q != oldprev) /* If ADD not last thing, */
break; /* just leave it alone. */
if ((o = q->Pindex) != 0 && o == r) break; /* give up */
q->Pop = P_MOVE; /* change to P_XMOVEI */
q->Pindex = s = foldcse(s, before(q));
flsprev(); /* Flush the OP we added */
if (o)
code0(P_ADD, q->Preg, o); /* followed by P_ADD */
code40(op, r, s, bsiz); /* then try code4 again */
return;
}
break;
} /* End of q->Ptype switch */
/* No simple optimizations found... */
/* Try folding index reg expression. Start with Q if we found one,
** to save time; otherwise start from just before new instruction.
*/
p->Pindex = foldcse(s, (q ? q : oldprev));
foldboth(); /* Check remaining optimizations */
}
/*
** single register codes
**
** code5 (op, r)
** generates op r, for ops like P_SETZ.
*/
void
code5(op, reg)
VREG *reg;
{
PCODE *p, *q;
int r = realreg (reg); /* get number for register */
if (debpho) {
shohdr();
fprintf(fpho,"CODE5: %o=%s %o,\n", op, popostr[op&POF_OPCODE], r);
}
p = newcode(); /* Add the instruction */
p->Ptype = PTA_ONEREG;
p->Pop = op;
p->Preg = r;
if (optobj)
switch (op) {
case P_SETZ:
case P_SETO:
if ((q = before(p))
&& q->Pop == op
&& q->Ptype == PTA_ONEREG /* && !prevskips */) {
/*
** fold: SETZ S, / SETZ R, (or SETO)
** into: SETZB S,R (or SETOB)
*/
p->Ptype = PTA_REGIS;
p->Pop |= POF_BOTH;
p->Pr2 = r;
flspop(p); /* Flush instr we just added */
break;
}
if (op == P_SETZ) foldmove(p);
}
if (debpho) shocum();
}
/*
** Codes involving local labels.
** Generates op r,$s. This is mostly used for jumps.
*/
void
code6 (op, reg, s)
SYMBOL *s;
VREG *reg;
{
int r = realreg (reg), skipped;
PCODE *p, *q;
if (debpho) {
shohdr();
fprintf(fpho,"CODE6: %o=%s %o,%s\n",
op, popostr[op&POF_OPCODE], r, (s ? s->Sname : ""));
}
if ((op & POF_OPCODE) == P_JUMP && previous != NULL && !isskip (previous->Pop)) {
/*
** emit P_JUMPx R,lab
** as P_CAIx R,0
** P_JRST lab
**
** So optimizer can work best. If it doesn't get folded,
** then further along in this routine this will get undone.
*/
r = ufcreg (r); /* code8 optimization loses w/o this */
code8 (op ^ (P_CAI ^ P_JUMP ^ POF_ISSKIP ^ POSF_INVSKIP), r, 0); /* compare to 0 */
foldskip (previous, 1); /* call peepholer */
op = P_JRST; /* make it a jump */
r = 0; /* P_JRST doesn't take a register */
}
if (op == P_JRST && optobj) foldjump (s); /* cascade and such */
if (op == P_JRST && safejump(previous)) { /* flush dead P_JRST */
if (debpho) shocum();
return;
}
reflabel (s, 1); /* adjust reference count for new op */
if (op == P_JRST && optobj && previous != NULL && !prevskips (previous))
switch (previous->Pop & POF_OPCODE) {
case P_CAI:
if (previous->Ptype != PTA_RCONST || previous->Pvalue != 0) break;
/*
** fold: P_CAIx R,0
** P_JRST lab
**
** into: P_JUMPx R,lab
*/
op = (previous->Pop ^ (P_CAI ^ P_JUMP ^ POF_ISSKIP ^ POSF_INVSKIP)); /* invert */
r = previous->Preg; /* get register from skip compare */
previous->Pop = P_NOP; /* flush the compare */
fixprev();
break;
case P_AOS:
if (previous->Ptype != PTA_REGIS) break;
op = (previous->Pop ^ (P_AOS ^ P_AOJ ^ POF_ISSKIP ^ POSF_INVSKIP));
r = previous->Pr2;
previous->Pop = P_NOP;
fixprev();
break;
case P_SOS:
if (previous->Ptype != PTA_REGIS) break;
op = (previous->Pop ^ (P_SOS ^ P_SOJ ^ POF_ISSKIP ^ POSF_INVSKIP));
r = previous->Pr2;
previous->Pop = P_NOP;
fixprev();
break;
case P_CAM:
/*
** fold: P_ADDI R,1
** P_CAMN R,x
** P_JRST $y
**
** into: P_SUB R,x
** P_AOJE R,$y
*/
if (previous->Pop & POSF_CMPSKIP) break; /* only P_CAMN and P_CAME */
for (p = before (previous);
p != NULL && p->Pop == P_MOVE && p->Preg != previous->Preg;
p = before (p)) ; /* skip over struct finding */
if (p == NULL || p->Preg != previous->Preg || p->Ptype != PTV_IMMED ||
p->Pvalue != 1 || prevskips (p)) break; /* look for OPI R,1 */
if (p->Pop == P_ADD) op = previous->Pop ^ (P_CAM ^ P_AOJ ^ POF_ISSKIP ^ POSF_INVSKIP);
else if (p->Pop != P_SUB) break; /* must be P_ADDI or P_SUBI */
else op = previous->Pop ^ (P_CAM ^ P_SOJ ^ POF_ISSKIP ^ POSF_INVSKIP); /* now P_SOJ */
r = p->Preg; /* use this register */
p->Pop = P_NOP; /* drop P_ADDI or P_SUBI */
previous->Pop = P_SUB; /* make P_SUB */
if ((p = before (p)) == NULL || p->Pop != P_JRST ||
(q = before (p)) == NULL || (q->Pop & (POF_OPCODE + POSF_CMPSKIP)) != P_CAM ||
q->Preg != r || !sameaddr (q, previous, 0) || prevskips (q)) break;
/*
** fold: P_CAMN R,x
** P_JRST $y
** P_SUB R,x
** P_AOJE R,$z
**
** into: P_SUB R,x
** P_JUMPE R,$y
** P_AOJE R,$z
*/
p->Preg = r; /* make P_JUMPE */
p->Pop = q->Pop ^ (P_CAM ^ P_JUMP ^ POF_ISSKIP ^ POSF_INVSKIP);
clrskip (p); /* not skipped */
q->Pop = P_SUB; /* make sub */
previous->Pop = P_NOP; /* drop duplicated P_SUB */
fixprev(); /* point to new peephole buf end */
}
/* all set up, drop values into the node */
skipped = (previous != NULL && isskip (previous->Pop));
p = newcode();
p->Ptype = PTA_MINDEXED;
p->Pop = op;
p->Preg = r;
p->Pptr = s;
p->Pindex = 0;
p->Poffset = 0;
if (skipped) setskip(p);
if (debpho) shocum();
}
/*
** General indexed instruction.
**
** Generates op preg,pptr+poffset(pindex)
** I.e. any complicated op with type PTA_MINDEXED.
** This is used to duplicate addressing of an already-generated op.
*/
void
code7 (op, preg, pptr, poffset, pindex)
VREG *preg, *pindex;
SYMBOL *pptr;
{
PCODE *p;
int rreg = realreg(preg), rindex = realreg(pindex), nreg;
if (rreg != rindex) release (pindex);
if (debpho) {
shohdr();
fprintf(fpho,"CODE7: %o=%s %o,%s+%o(%o)\n",
op, popostr[op&POF_OPCODE], rreg,
(pptr ? pptr->Sname : ""), poffset, rindex);
}
/* maybe do more complicated optimizing code generation */
if (pptr == NULL && poffset == 0) {
code4 (op, rreg, rindex);
if (debpho) shocum();
return;
}
nreg = ufcreg(rreg); /* undo failed changereg */
/* too general for optimization, just add the code */
p = newcode();
p->Ptype = PTA_MINDEXED;
p->Pop = op;
p->Preg = nreg;
p->Pptr = pptr;
p->Poffset = poffset;
p->Pindex = rindex;
if (nreg != rreg) /* Put result back in right register */
code0(P_MOVE, rreg, nreg);
if (debpho) shocum();
}
/*
** Register-constant codes.
**
** Like code1(), but op doesn't become immediate, making type PTA_RCONST.
** E.g. code8 (P_ADJSP, R_SP, n) where n is some stack offset.
*/
void
code8 (op, reg, val)
VREG *reg;
{
int r = realreg (reg);
PCODE *p;
if (debpho) {
shohdr();
fprintf(fpho,"CODE8: %o=%s %o,%o\n",
op, popostr[op&POF_OPCODE], r, val);
}
if (optobj) switch (op) {
case P_ADJSP:
while (previous != NULL && previous->Pop == P_PUSH && val < 0) {
previous->Pop = P_NOP; /* drop lost push */
fixprev(); /* point to new end of peephole buff */
val++; /* account for it in adjustment */
}
val = foldstack (val);
if (val == 0) { /* If completely folded, can return */
if (debpho) shocum();
return;
}
break;
#if 0
/* Perhaps this should be flushed, as all it does is check to see
** whether attempting to convert a double-word zero value into a
** double floating-point number. CCGEN2 should be able to know this.
*/
case P_TLC:
if (val != 0243000) break; /* make sure int=>double coercion */
case P_ASHC: /* const zero needs no coercion */
if (previous != NULL && previous->Preg == r && previous->Pr2 == r+1 &&
previous->Ptype == PTA_REGIS && previous->Pop == P_SETZ+POF_BOTH) {
if (debpho) shocum();
return;
}
#endif
}
p = newcode();
p->Ptype = PTA_RCONST;
p->Pop = op;
p->Preg = r;
p->Pvalue = val;
foldskip(p, 0); /* Could be from switch, be careful */
if (op == P_ADJSP
&& (p = before(previous)) != NULL
&& p->Ptype == PTV_IINDEXED) {
if (p->Pindex == R_SP) p->Poffset -= val; /* adj stack addr for swap */
swappseudo(p, previous); /* get out of way of tail recurse */
}
if (debpho) shocum();
}
/*
** Floating point.
** Generates op r,[float] i.e. floating point literal.
** Grave misunderstandings will result if the "twowds" flag
** does not match the op specified!
** Either that flag or the op are valid ways of determining
** whether we are dealing with a 1 or 2 word constant.
*/
void
code9 (op, r, value, twowds)
double value;
int twowds; /* TRUE if 2 wds (double), else 1-wd float */
{
PCODE *p;
r = realreg (r);
if (debpho) {
shohdr();
fprintf(fpho,"CODE9: %o=%s %o,[%.20g]\n",
op, popostr[op&POF_OPCODE], r, value);
}
/* Optimize a P_MOVE or P_DMOVE of 0.0 since floating point zero is
* same as integer zero.
*/
if (value == 0.0 && optobj)
switch(op) {
case P_DMOVE: /* Make DMOVE R,[0 ? 0] be SETZB R,R+1 */
/* Can't use code0 as that would release r+1 */
p = newcode(); /* Add the instruction */
p->Ptype = PTA_REGIS;
p->Pop = P_SETZ+POF_BOTH;
p->Preg = r;
p->Pr2 = r+1;
if (debpho) shocum();
return;
case P_MOVE:
code5(P_SETZ, r);
if (debpho) shocum();
return;
}
p = newcode();
p->Ptype = (twowds ? PTA_DCONST : PTA_FCONST);
p->Pop = op;
p->Preg = r;
if (twowds) p->Pdouble = value;
else p->Pfloat = (float) value;
if (optobj) foldmove(p); /* see if already have this one */
if (debpho) shocum();
}
/*
** Pointer constant operands.
** Generates op r,[pointer] i.e. a pointer literal.
** The pointer is made from an:
** address (pointer to a symbol)
** offset (in bytes from address)
** bytesize (0,6,7,8,9,18)
** Using this information, CCOUT constructs a byte or word pointer using
** symbolic references which are resolved at load time into whatever
** the proper values are, whether local or OWGBP format (non-extended or
** extended).
** A bytesize of -1 is special and indicates that a MASK is desired
** for the P+S field of a byte-pointer. This should never be used with
** an address or offset.
** When used with the P_PTRCNV op (which converts a pointer in
** the register), the offset indicates the byte size of the current pointer,
** and the bsize indicates the desired byte size to convert it to.
** The address must be NULL.
*/
void
code10(op, r, addr, bsize, offset)
SYMBOL *addr;
{
PCODE *p;
int nreg;
r = realreg (r);
if (debpho) {
shohdr();
fprintf(fpho,"CODE10: %o=%s %o,[%s+%o (size %d)]\n",
op, popostr[op&POF_OPCODE], r,
(addr ? addr->Sname : ""), offset, bsize);
}
nreg = ufcreg(r); /* undo failed changereg */
/* this goes with the code0 call below */
p = newcode();
p->Ptype = PTA_PCONST;
p->Pop = op;
p->Preg = nreg;
p->Pptr = addr;
p->Poffset = offset;
p->Pbsize = bsize;
if (nreg != r) code0(P_MOVE, r, nreg);
if (optobj && op == P_MOVE)
foldmove(previous); /* see if already have this one */
if (debpho) shocum();
}
/*
** Indexed immediate.
**
** Generates opI r,(s)
** Called by pctopi() to make an P_XMOVEI and flatten the byte pointer.
*/
void
code11 (op, r, s)
{
PCODE *p;
r = realreg (r);
s = ufcreg (realreg (s));
if (debpho) {
shohdr();
fprintf(fpho,"CODE11: %o=%s %o,(%o)\n",
op, popostr[op&POF_OPCODE], r, s);
}
p = newcode();
p->Ptype = PTV_IINDEXED;
p->Pop = op;
p->Preg = r;
p->Pptr = NULL;
p->Poffset = 0;
p->Pindex = s;
if (debpho) shocum();
}
/*
** Local, from memory.
**
** Generates op r,s(17)
** This is used by the register allocation code to despill registers.
*/
void
code12 (op, r, offset)
{
PCODE *p;
r = realreg(r);
if (debpho) {
shohdr();
fprintf(fpho,"CODE12: %o=%s %o,%o(17)\n",
op, popostr[op&POF_OPCODE], r, offset);
}
p = newcode();
p->Ptype = PTA_MINDEXED;
p->Pop = op;
p->Preg = r;
p->Pptr = NULL;
p->Poffset = offset;
p->Pindex = R_SP;
if (debpho) shocum();
}
/*
** Local, immediate.
**
** Generates opI r,s(17) i.e. an P_XMOVEI of a stack location.
** As far as I know the only op used is P_XMOVEI.
*/
void
code13 (op, r, offset)
{
PCODE *p;
r = realreg(r);
if (debpho) {
shohdr();
fprintf(fpho,"CODE13: %o=%s+I %o,%o(17)\n",
op, popostr[op&POF_OPCODE], r, offset);
}
p = newcode();
p->Ptype = PTV_IINDEXED;
p->Pop = op;
p->Preg = r;
p->Pptr = NULL;
p->Poffset = offset;
p->Pindex = R_SP;
if (debpho) shocum();
}
/*
** Indirect indexed local label
**
** Generates op @$lab+off(ind)
** Used with op=P_JRST for switch jump tables.
*/
void
code15 (op, lab, off, idx)
SYMBOL *lab;
VREG *idx;
{
PCODE *p;
int i = realreg(idx);
if (debpho) {
shohdr();
fprintf(fpho,"CODE15: %o=%s @%s+%o(%o)\n",
op, popostr[op&POF_OPCODE],
(lab ? lab->Sname : ""), off, idx);
}
p = newcode();
p->Ptype = PTA_MINDEXED+PTF_IND;
p->Pop = op;
p->Preg = 0;
p->Pptr = lab;
p->Poffset = off;
p->Pindex = i;
if (debpho) shocum();
}
/*
** Indexed local label.
** Generates op r,$lab(q). Used for checking switch hash tables.
*/
void
code16 (op, r, lab, s)
SYMBOL *lab;
{
PCODE *p;
r = realreg(r);
s = realreg(s);
if (debpho) {
shohdr();
fprintf(fpho,"CODE16: %o=%s %o,%s(%o)\n",
op, popostr[op&POF_OPCODE], r,
(lab ? lab->Sname : ""), s);
}
p = newcode();
p->Ptype = PTA_MINDEXED;
p->Pop = op;
p->Preg = r;
p->Pptr = lab;
p->Poffset = 0;
p->Pindex = s;
if (debpho) shocum();
}
/*
** Simple value.
** Generates a literal value. Used for generating switch hash tables.
*/
void
code17(value)
{
PCODE *p;
if (debpho) {
fprintf(fpho,"CODE17: literal %o\n", value);
}
p = newcode();
p->Ptype = PTA_RCONST;
p->Preg = 0;
p->Pop = P_CVALUE;
p->Pvalue = value;
if (debpho) shocum();
}
/* CODESTR - Generate "code" consisting of a direct user-specified
** assembly language string. This implements the asm() construction.
*/
void
codestr(s, len)
char *s;
int len;
{
flushcode(); /* Ensure pcode buffer flushed */
while (--len >= 0) outc(*s++);
}
/* CODLABEL, CODGOLAB - Generate "code" consisting of the given label symbol.
** codlab does more optimization and may not actually emit the label.
** codgolab always emits its label; it is used for goto labels.
*/
/* CODLABEL - Emit a (forward) label.
**
** Optimizations are performed and if the label still has references
** to it, it is emitted. Then realfreelabel() is called on it, and
** if we emitted it and thus cleared the peephole buffer we also free
** the list of labels queued by freelabel().
*/
void
codlabel(lab)
SYMBOL *lab;
{
int after;
if (debpho) {
shohdr();
fprintf(fpho, "CODLAB: %s\n", lab->Sname);
}
after = hackstack(lab); /* pull ADJSP across POPJ */
optlab(lab); /* call peephole optimizer */
if (lab->Svalue > 0) { /* See if still must emit */
if (debpho) shocum(); /* Yes, report changes prior to */
flushcode(); /* clearing out previous code. */
outlab(lab); /* Now emit label. */
cleanlabs(); /* Now OK to clean up queued labels */
}
if (after)
code8(P_ADJSP, R_SP, after); /* fix up stack */
freelabel(lab);
if (debpho) shocum();
}
/* CODGOLAB - Emit a GOTO type label.
** These are not as well behaved as loop and if labels so we can't do as much.
*/
void
codgolab(lab)
SYMBOL *lab;
{
if (debpho) {
shohdr();
fprintf(fpho, "CODGOLAB: %s\n", lab->Sname);
}
optlab(lab); /* optimize */
flushcode(); /* Clear out previous code */
outlab(lab); /* and unconditionally emit label */
if (debpho) shocum();
}
/* This code should be flushed eventually,
** and TXO, TXZ, TXC forms substituted for this silly nonsense.
*/
/* ------------------------------------------------------ */
/* return immediate version of boolean operator */
/* ------------------------------------------------------ */
immedop(op)
{
switch (op & POF_OPCODE) {
case P_CAM: return op ^ (P_CAM ^ P_CAI);
case P_TDN: return op ^ (P_TDN ^ P_TRN);
case P_TDO: return op ^ (P_TDO ^ P_TRO);
case P_TDC: return op ^ (P_TDC ^ P_TRC);
case P_TDZ: return op ^ (P_TDZ ^ P_TRZ);
default: return 0;
}
}
directop(op)
{
switch (op & POF_OPCODE) {
case P_CAI: return op ^ (P_CAM ^ P_CAI);
case P_TRN: return op ^ (P_TDN ^ P_TRN);
case P_TRO: return op ^ (P_TDO ^ P_TRO);
case P_TRC: return op ^ (P_TDC ^ P_TRC);
case P_TRZ: return op ^ (P_TDZ ^ P_TRZ);
default: return 0;
}
}