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realemu: implement IDIV, mark 0xE0000 writeable, fix DIV overfow trap

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This commit is contained in:
mischief 2014-02-01 12:27:07 -08:00
parent 08bb4afb52
commit 1fe36bf849
1 changed files with 49 additions and 2 deletions
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51
sys/src/cmd/aux/realemu/xec.c
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@ -769,12 +769,58 @@ opdiv(Cpu *cpu, Inst *i)
n = (uvlong)ar(ra)<<s | (uvlong)ar(qa);
q = n/d;
if(q > m)
trap(cpu, EGPF);
trap(cpu, EDIV0);
r = n%d;
aw(ra, r);
aw(qa, q);
}
static void
opidiv(Cpu *cpu, Inst *i)
{
Iarg *qa, *ra;
vlong n, q, min, max;
long r, d;
int s;
s = i->a1->len*8;
d = ars(i->a1);
if(d == 0)
trap(cpu, EDIV0);
if(s == 8){
qa = areg(cpu, 1, RAX);
ra = adup(qa);
ra->tag |= TH;
} else {
qa = areg(cpu, i->olen, RAX);
ra = areg(cpu, i->olen, RDX);
}
n = (vlong)ars(ra)<<s | (uvlong)ars(qa);
q = n/d;
r = n%d;
/* check for overflow based on operand size */
switch(s) {
case 8:
min = (char)0x80;
max = 0x7F;
break;
case 16:
min = (short)0x8000;
max = 0x7FFF;
break;
case 32:
min = (long)0x80000000;
max = 0x7FFFFFFF;
break;
}
if(q > max || q < min)
trap(cpu, EDIV0);
aw(ra, r);
aw(qa, q);
}
static int
cctrue(Cpu *cpu, Inst *i)
@ -1249,6 +1295,7 @@ static void (*exctab[NUMOP])(Cpu *cpu, Inst*) = {
[OMUL] = opmul,
[OIMUL] = opimul,
[ODIV] = opdiv,
[OIDIV] = opidiv,
[OLEA] = oplea,
[OMOV] = opmov,