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realemu: handle address overflow

cinap_lenrek 2011-04-29 05:49:58 +00:00
parent daef42e6b3
commit c0ebaf7ee8
1 changed files with 37 additions and 26 deletions
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63
sys/src/cmd/aux/realemu/xec.c
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@ -15,6 +15,7 @@ push(Iarg *sp, Iarg *a)
p = amem(sp->cpu, a->len, RSS, ar(sp));
p->off -= a->len;
p->off &= mask(sp->len*8);
aw(p, ar(a));
aw(sp, p->off);
}
@ -495,12 +496,9 @@ opbittest(Cpu *cpu, Inst *i)
x = i->a1;
s = x->len*8;
if(x->tag == TMEM){
int z;
x = adup(x);
x->off += (n / s) * x->len;
z = i->alen*8;
x->off &= mask(z);
x->off &= mask(i->alen*8);
}
a = ar(x);
n &= s-1;
@ -972,9 +970,10 @@ static void
opmovs(Cpu *cpu, Inst *i)
{
Iarg *cx, *d, *s;
ulong c;
ulong c, m;
int n;
m = mask(i->alen*8);
d = adup(i->a1);
s = adup(i->a2);
n = s->len;
@ -990,7 +989,9 @@ opmovs(Cpu *cpu, Inst *i)
while(c){
aw(d, ar(s));
d->off += n;
d->off &= m;
s->off += n;
s->off &= m;
c--;
}
aw(areg(cpu, i->alen, RDI), d->off);
@ -1003,9 +1004,10 @@ static void
oplods(Cpu *cpu, Inst *i)
{
Iarg *cx, *s;
ulong c;
ulong c, m;
int n;
m = mask(i->alen*8);
s = adup(i->a2);
n = s->len;
if(cpu->reg[RFL] & DF)
@ -1019,8 +1021,10 @@ oplods(Cpu *cpu, Inst *i)
}
if(c){
s->off += n*(c-1);
s->off &= m;
aw(i->a1, ar(s));
s->off += n;
s->off &= m;
}
aw(areg(cpu, i->alen, RSI), s->off);
if(cx)
@ -1031,9 +1035,10 @@ static void
opstos(Cpu *cpu, Inst *i)
{
Iarg *cx, *d;
ulong c, a;
ulong c, a, m;
int n;
m = mask(i->alen*8);
d = adup(i->a1);
n = d->len;
if(cpu->reg[RFL] & DF)
@ -1049,6 +1054,7 @@ opstos(Cpu *cpu, Inst *i)
while(c){
aw(d, a);
d->off += n;
d->off &= m;
c--;
}
aw(areg(cpu, i->alen, RDI), d->off);
@ -1059,26 +1065,25 @@ opstos(Cpu *cpu, Inst *i)
static int
repcond(Cpu *cpu, int rep)
{
switch(rep){
case OREPNE:
if(rep == OREPNE)
return (cpu->reg[RFL] & ZF) == 0;
case OREPE:
default:
return !rep || (cpu->reg[RFL] & ZF) != 0;
}
return !rep || (cpu->reg[RFL] & ZF) != 0;
}
static void
opscas(Cpu *cpu, Inst *i)
{
Iarg *cx, *s;
ulong c;
Iarg *cx, *d;
ulong *f, c, m;
long a;
int n;
int n, z;
s = adup(i->a1);
n = s->len;
if(cpu->reg[RFL] & DF)
m = mask(i->alen*8);
d = adup(i->a1);
n = d->len;
z = n*8;
f = cpu->reg + RFL;
if(*f & DF)
n = -n;
if(i->rep){
cx = areg(cpu, i->alen, RCX);
@ -1089,13 +1094,14 @@ opscas(Cpu *cpu, Inst *i)
}
a = ars(i->a2);
while(c){
sub(cpu->reg + RFL, a, ars(s), 0, s->len*8);
s->off += n;
sub(f, a, ars(d), 0, z);
d->off += n;
d->off &= m;
c--;
if(repcond(cpu, i->rep))
break;
}
aw(areg(cpu, i->alen, RDI), s->off);
aw(areg(cpu, i->alen, RDI), d->off);
if(cx)
aw(cx, c);
}
@ -1104,13 +1110,16 @@ static void
opcmps(Cpu *cpu, Inst *i)
{
Iarg *cx, *s, *d;
ulong c;
int n;
ulong *f, c, m;
int n, z;
m = mask(i->alen*8);
d = adup(i->a1);
s = adup(i->a2);
n = s->len;
if(cpu->reg[RFL] & DF)
z = n*8;
f = cpu->reg + RFL;
if(*f & DF)
n = -n;
if(i->rep){
cx = areg(cpu, i->alen, RCX);
@ -1120,9 +1129,11 @@ opcmps(Cpu *cpu, Inst *i)
c = 1;
}
while(c){
sub(cpu->reg + RFL, ars(s), ars(d), 0, s->len*8);
sub(f, ars(s), ars(d), 0, z);
s->off += n;
s->off &= m;
d->off += n;
d->off &= m;
c--;
if(repcond(cpu, i->rep))
break;