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KVM: x86 emulator: cmps instruction

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Add emulation for the cmps instruction.  This lets OpenBSD boot on kvm.

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Guillaume Thouvenin 2007-11-26 13:49:09 +01:00 committed by Avi Kivity
parent e8d8d7fe88
commit d7e5117a25
1 changed files with 56 additions and 2 deletions
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58
drivers/kvm/x86_emulate.c
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@ -1535,10 +1535,31 @@ special_insn:
break;
}
if (c->rep_prefix) {
/* All REP prefixes have the same first termination condition */
if (c->regs[VCPU_REGS_RCX] == 0) {
ctxt->vcpu->rip = c->eip;
goto done;
}
/* The second termination condition only applies for REPE
* and REPNE. Test if the repeat string operation prefix is
* REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
* corresponding termination condition according to:
* - if REPE/REPZ and ZF = 0 then done
* - if REPNE/REPNZ and ZF = 1 then done
*/
if ((c->b == 0xa6) || (c->b == 0xa7) ||
(c->b == 0xae) || (c->b == 0xaf)) {
if ((c->rep_prefix == REPE_PREFIX) &&
((ctxt->eflags & EFLG_ZF) == 0)) {
ctxt->vcpu->rip = c->eip;
goto done;
}
if ((c->rep_prefix == REPNE_PREFIX) &&
((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {
ctxt->vcpu->rip = c->eip;
goto done;
}
}
c->regs[VCPU_REGS_RCX]--;
c->eip = ctxt->vcpu->rip;
}
@ -1564,8 +1585,41 @@ special_insn:
: c->dst.bytes);
break;
case 0xa6 ... 0xa7: /* cmps */
DPRINTF("Urk! I don't handle CMPS.\n");
goto cannot_emulate;
c->src.type = OP_NONE; /* Disable writeback. */
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->src.ptr = (unsigned long *)register_address(
c->override_base ? *c->override_base :
ctxt->ds_base,
c->regs[VCPU_REGS_RSI]);
if ((rc = ops->read_emulated((unsigned long)c->src.ptr,
&c->src.val,
c->src.bytes,
ctxt->vcpu)) != 0)
goto done;
c->dst.type = OP_NONE; /* Disable writeback. */
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.ptr = (unsigned long *)register_address(
ctxt->es_base,
c->regs[VCPU_REGS_RDI]);
if ((rc = ops->read_emulated((unsigned long)c->dst.ptr,
&c->dst.val,
c->dst.bytes,
ctxt->vcpu)) != 0)
goto done;
DPRINTF("cmps: mem1=0x%p mem2=0x%p\n", c->src.ptr, c->dst.ptr);
emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
register_address_increment(c->regs[VCPU_REGS_RSI],
(ctxt->eflags & EFLG_DF) ? -c->src.bytes
: c->src.bytes);
register_address_increment(c->regs[VCPU_REGS_RDI],
(ctxt->eflags & EFLG_DF) ? -c->dst.bytes
: c->dst.bytes);
break;
case 0xaa ... 0xab: /* stos */
c->dst.type = OP_MEM;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;