692 lines
10 KiB
C
692 lines
10 KiB
C
#include "gc.h"
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void
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peep(void)
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{
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Reg *r, *r1, *r2;
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Prog *p, *p1;
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int t;
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/*
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* complete R structure
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*/
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t = 0;
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for(r=firstr; r!=R; r=r1) {
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r1 = r->link;
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if(r1 == R)
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break;
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p = r->prog->link;
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while(p != r1->prog)
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switch(p->as) {
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default:
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r2 = rega();
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r->link = r2;
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r2->link = r1;
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r2->prog = p;
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r2->p1 = r;
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r->s1 = r2;
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r2->s1 = r1;
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r1->p1 = r2;
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r = r2;
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t++;
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case ADATA:
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case AGLOBL:
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case ANAME:
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case ASIGNAME:
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p = p->link;
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}
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}
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loop1:
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t = 0;
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for(r=firstr; r!=R; r=r->link) {
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p = r->prog;
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if(p->as == AMOVW || p->as == AFMOVF || p->as == AFMOVD)
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if(regtyp(&p->to)) {
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if(regtyp(&p->from))
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if(p->from.type == p->to.type) {
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if(copyprop(r)) {
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excise(r);
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t++;
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} else
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if(subprop(r) && copyprop(r)) {
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excise(r);
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t++;
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}
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}
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if(regzer(&p->from))
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if(p->to.type == D_REG) {
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p->from.type = D_REG;
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p->from.reg = 0;
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if(copyprop(r)) {
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excise(r);
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t++;
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} else
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if(subprop(r) && copyprop(r)) {
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excise(r);
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t++;
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}
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}
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}
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}
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if(t)
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goto loop1;
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/*
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* look for MOVB x,R; MOVB R,R
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*/
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for(r=firstr; r!=R; r=r->link) {
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p = r->prog;
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switch(p->as) {
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default:
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continue;
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case AMOVH:
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case AMOVHU:
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case AMOVB:
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case AMOVBU:
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if(p->to.type != D_REG)
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continue;
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break;
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}
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r1 = r->link;
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if(r1 == R)
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continue;
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p1 = r1->prog;
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if(p1->as != p->as)
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continue;
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if(p1->from.type != D_REG || p1->from.reg != p->to.reg)
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continue;
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if(p1->to.type != D_REG || p1->to.reg != p->to.reg)
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continue;
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excise(r1);
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}
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}
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void
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excise(Reg *r)
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{
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Prog *p;
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p = r->prog;
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p->as = ANOP;
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p->from = zprog.from;
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p->to = zprog.to;
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p->reg = zprog.reg; /**/
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}
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Reg*
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uniqp(Reg *r)
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{
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Reg *r1;
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r1 = r->p1;
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if(r1 == R) {
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r1 = r->p2;
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if(r1 == R || r1->p2link != R)
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return R;
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} else
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if(r->p2 != R)
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return R;
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return r1;
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}
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Reg*
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uniqs(Reg *r)
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{
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Reg *r1;
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r1 = r->s1;
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if(r1 == R) {
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r1 = r->s2;
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if(r1 == R)
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return R;
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} else
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if(r->s2 != R)
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return R;
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return r1;
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}
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regzer(Adr *a)
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{
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if(a->type == D_CONST)
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if(a->sym == S)
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if(a->offset == 0)
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return 1;
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if(a->type == D_REG)
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if(a->reg == 0)
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return 1;
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return 0;
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}
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regtyp(Adr *a)
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{
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if(a->type == D_REG) {
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if(a->reg != 0)
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return 1;
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return 0;
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}
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if(a->type == D_FREG)
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return 1;
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return 0;
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}
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/*
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* the idea is to substitute
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* one register for another
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* from one MOV to another
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* MOV a, R0
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* ADD b, R0 / no use of R1
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* MOV R0, R1
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* would be converted to
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* MOV a, R1
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* ADD b, R1
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* MOV R1, R0
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* hopefully, then the former or latter MOV
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* will be eliminated by copy propagation.
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*/
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int
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subprop(Reg *r0)
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{
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Prog *p;
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Adr *v1, *v2;
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Reg *r;
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int t;
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p = r0->prog;
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v1 = &p->from;
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if(!regtyp(v1))
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return 0;
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v2 = &p->to;
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if(!regtyp(v2))
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return 0;
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for(r=uniqp(r0); r!=R; r=uniqp(r)) {
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if(uniqs(r) == R)
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break;
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p = r->prog;
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switch(p->as) {
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case AJMPL:
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return 0;
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case AADD:
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case ASUB:
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case ASLL:
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case ASRL:
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case ASRA:
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case AOR:
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case AAND:
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case AXOR:
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case AMUL:
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case ADIV:
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case ADIVL:
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case AMOD:
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case AMODL:
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case AFADDD:
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case AFADDF:
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case AFSUBD:
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case AFSUBF:
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case AFMULD:
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case AFMULF:
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case AFDIVD:
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case AFDIVF:
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if(p->to.type == v1->type)
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if(p->to.reg == v1->reg) {
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if(p->reg == NREG)
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p->reg = p->to.reg;
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goto gotit;
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}
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break;
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case AFMOVF:
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case AFMOVD:
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case AMOVW:
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if(p->to.type == v1->type)
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if(p->to.reg == v1->reg)
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goto gotit;
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break;
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}
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if(copyau(&p->from, v2) ||
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copyau1(p, v2) ||
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copyau(&p->to, v2))
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break;
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if(copysub(&p->from, v1, v2, 0) ||
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copysub1(p, v1, v2, 0) ||
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copysub(&p->to, v1, v2, 0))
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break;
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}
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return 0;
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gotit:
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copysub(&p->to, v1, v2, 1);
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if(debug['P']) {
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print("gotit: %D->%D\n%P", v1, v2, r->prog);
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if(p->from.type == v2->type)
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print(" excise");
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print("\n");
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}
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for(r=uniqs(r); r!=r0; r=uniqs(r)) {
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p = r->prog;
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copysub(&p->from, v1, v2, 1);
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copysub1(p, v1, v2, 1);
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copysub(&p->to, v1, v2, 1);
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if(debug['P'])
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print("%P\n", r->prog);
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}
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t = v1->reg;
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v1->reg = v2->reg;
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v2->reg = t;
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if(debug['P'])
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print("%P last\n", r->prog);
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return 1;
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}
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/*
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* The idea is to remove redundant copies.
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* v1->v2 F=0
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* (use v2 s/v2/v1/)*
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* set v1 F=1
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* use v2 return fail
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* -----------------
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* v1->v2 F=0
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* (use v2 s/v2/v1/)*
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* set v1 F=1
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* set v2 return success
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*/
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int
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copyprop(Reg *r0)
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{
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Prog *p;
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Adr *v1, *v2;
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Reg *r;
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p = r0->prog;
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v1 = &p->from;
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v2 = &p->to;
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if(copyas(v1, v2))
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return 1;
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for(r=firstr; r!=R; r=r->link)
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r->active = 0;
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return copy1(v1, v2, r0->s1, 0);
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}
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copy1(Adr *v1, Adr *v2, Reg *r, int f)
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{
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int t;
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Prog *p;
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if(r->active) {
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if(debug['P'])
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print("act set; return 1\n");
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return 1;
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}
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r->active = 1;
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if(debug['P'])
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print("copy %D->%D f=%d\n", v1, v2, f);
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for(; r != R; r = r->s1) {
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p = r->prog;
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if(debug['P'])
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print("%P", p);
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if(!f && uniqp(r) == R) {
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f = 1;
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if(debug['P'])
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print("; merge; f=%d", f);
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}
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t = copyu(p, v2, A);
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switch(t) {
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case 2: /* rar, cant split */
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if(debug['P'])
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print("; %Drar; return 0\n", v2);
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return 0;
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case 3: /* set */
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if(debug['P'])
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print("; %Dset; return 1\n", v2);
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return 1;
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case 1: /* used, substitute */
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case 4: /* use and set */
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if(f) {
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if(!debug['P'])
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return 0;
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if(t == 4)
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print("; %Dused+set and f=%d; return 0\n", v2, f);
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else
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print("; %Dused and f=%d; return 0\n", v2, f);
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return 0;
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}
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if(copyu(p, v2, v1)) {
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if(debug['P'])
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print("; sub fail; return 0\n");
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return 0;
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}
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if(debug['P'])
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print("; sub%D/%D", v2, v1);
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if(t == 4) {
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if(debug['P'])
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print("; %Dused+set; return 1\n", v2);
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return 1;
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}
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break;
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}
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if(!f) {
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t = copyu(p, v1, A);
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if(!f && (t == 2 || t == 3 || t == 4)) {
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f = 1;
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if(debug['P'])
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print("; %Dset and !f; f=%d", v1, f);
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}
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}
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if(debug['P'])
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print("\n");
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if(r->s2)
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if(!copy1(v1, v2, r->s2, f))
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return 0;
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}
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return 1;
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}
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/*
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* return
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* 1 if v only used (and substitute),
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* 2 if read-alter-rewrite
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* 3 if set
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* 4 if set and used
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* 0 otherwise (not touched)
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*/
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int
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copyu(Prog *p, Adr *v, Adr *s)
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{
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switch(p->as) {
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default:
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if(debug['P'])
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print(" (???)");
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return 2;
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case ANOP: /* read, write */
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case AMOVW:
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case AMOVH:
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case AMOVHU:
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case AMOVB:
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case AMOVBU:
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case AFMOVF:
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case AFMOVD:
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case AFMOVDW:
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case AFMOVWD:
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case AFMOVFW:
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case AFMOVWF:
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case AFMOVFD:
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case AFMOVDF:
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if(s != A) {
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if(copysub(&p->from, v, s, 1))
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return 1;
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if(!copyas(&p->to, v))
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if(copysub(&p->to, v, s, 1))
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return 1;
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return 0;
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}
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if(copyas(&p->to, v)) {
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if(copyau(&p->from, v))
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return 4;
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return 3;
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}
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if(copyau(&p->from, v))
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return 1;
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if(copyau(&p->to, v))
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return 1;
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return 0;
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case AADD: /* read read write */
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case ASUB:
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case ASLL:
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case ASRL:
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case ASRA:
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case AOR:
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case AAND:
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case AXOR:
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case AMUL:
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case ADIV:
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case ADIVL:
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case AMOD:
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case AMODL:
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case AFADDF:
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case AFADDD:
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case AFSUBF:
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case AFSUBD:
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case AFMULF:
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case AFMULD:
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case AFDIVF:
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case AFDIVD:
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if(s != A) {
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if(copysub(&p->from, v, s, 1))
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return 1;
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if(copysub1(p, v, s, 1))
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return 1;
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if(!copyas(&p->to, v))
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if(copysub(&p->to, v, s, 1))
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return 1;
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return 0;
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}
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if(copyas(&p->to, v)) {
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if(p->reg == NREG)
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p->reg = p->to.reg;
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if(copyau(&p->from, v))
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return 4;
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if(copyau1(p, v))
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return 4;
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return 3;
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}
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if(copyau(&p->from, v))
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return 1;
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if(copyau1(p, v))
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return 1;
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if(copyau(&p->to, v))
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return 1;
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return 0;
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case ABA: /* no reference */
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case ABCC:
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case ABCS:
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case ABE:
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case ABG:
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case ABGE:
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case ABGU:
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case ABL:
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case ABLE:
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case ABLEU:
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case ABN:
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case ABNE:
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case ABNEG:
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case ABPOS:
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case ABVC:
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case ABVS:
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case AFBA:
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case AFBE:
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case AFBG:
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case AFBGE:
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case AFBL:
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case AFBLE:
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case AFBNE:
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case AFBN:
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case AFBLG:
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case AFBO:
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case AFBU:
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case AFBUE:
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case AFBUG:
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case AFBUGE:
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case AFBUL:
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case AFBULE:
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break;
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case ACMP: /* read read */
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case AFCMPD:
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case AFCMPF:
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if(s != A) {
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if(copysub(&p->from, v, s, 1))
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return 1;
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return copysub(&p->to, v, s, 1);
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}
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if(copyau(&p->from, v))
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return 1;
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if(copyau(&p->to, v))
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return 1;
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break;
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case AJMP: /* funny */
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if(s != A) {
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if(copysub(&p->to, v, s, 1))
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return 1;
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return 0;
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}
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if(copyau(&p->to, v))
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return 1;
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return 0;
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case ARETURN: /* funny */
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if(v->type == D_REG)
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if(v->reg == REGRET)
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return 2;
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if(v->type == D_FREG)
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if(v->reg == FREGRET)
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return 2;
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case AJMPL: /* funny */
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if(v->type == D_REG) {
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if(v->reg <= REGEXT && v->reg > exregoffset)
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return 2;
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if(v->reg == REGARG)
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return 2;
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}
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if(v->type == D_FREG) {
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if(v->reg <= FREGEXT && v->reg > exfregoffset)
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return 2;
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}
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if(s != A) {
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if(copysub(&p->to, v, s, 1))
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return 1;
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return 0;
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}
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if(copyau(&p->to, v))
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return 4;
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return 3;
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case ATEXT: /* funny */
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if(v->type == D_REG)
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if(v->reg == REGARG)
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return 3;
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return 0;
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}
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return 0;
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}
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int
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a2type(Prog *p)
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{
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switch(p->as) {
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case AADD:
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case ASUB:
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|
case ASLL:
|
|
case ASRL:
|
|
case ASRA:
|
|
case AOR:
|
|
case AAND:
|
|
case AXOR:
|
|
case AMUL:
|
|
case ADIV:
|
|
case ADIVL:
|
|
case AMOD:
|
|
case AMODL:
|
|
return D_REG;
|
|
|
|
case AFADDF:
|
|
case AFADDD:
|
|
case AFSUBF:
|
|
case AFSUBD:
|
|
case AFMULF:
|
|
case AFMULD:
|
|
case AFDIVF:
|
|
case AFDIVD:
|
|
return D_FREG;
|
|
}
|
|
return D_NONE;
|
|
}
|
|
|
|
/*
|
|
* direct reference,
|
|
* could be set/use depending on
|
|
* semantics
|
|
*/
|
|
int
|
|
copyas(Adr *a, Adr *v)
|
|
{
|
|
|
|
if(regtyp(v))
|
|
if(a->type == v->type)
|
|
if(a->reg == v->reg)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* either direct or indirect
|
|
*/
|
|
int
|
|
copyau(Adr *a, Adr *v)
|
|
{
|
|
|
|
if(copyas(a, v))
|
|
return 1;
|
|
if(v->type == D_REG)
|
|
if(a->type == D_OREG)
|
|
if(v->reg == a->reg)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
copyau1(Prog *p, Adr *v)
|
|
{
|
|
|
|
if(regtyp(v))
|
|
if(p->from.type == v->type || p->to.type == v->type)
|
|
if(p->reg == v->reg) {
|
|
if(a2type(p) != v->type)
|
|
print("botch a2type %P\n", p);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* substitute s for v in a
|
|
* return failure to substitute
|
|
*/
|
|
int
|
|
copysub(Adr *a, Adr *v, Adr *s, int f)
|
|
{
|
|
|
|
if(f)
|
|
if(copyau(a, v))
|
|
a->reg = s->reg;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
copysub1(Prog *p1, Adr *v, Adr *s, int f)
|
|
{
|
|
|
|
if(f)
|
|
if(copyau1(p1, v))
|
|
p1->reg = s->reg;
|
|
return 0;
|
|
}
|