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KVM: x86 emulator: simplify r/m decoding 

Consolidate the duplicated code when not in any special case.

Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Avi Kivity 2008-06-15 21:53:26 -07:00
parent dc71d0f162
commit 84411d85da
1 changed files with 4 additions and 13 deletions
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17
arch/x86/kvm/x86_emulate.c
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@ -740,9 +740,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
c->modrm_ea = (u16)c->modrm_ea;
} else {
/* 32/64-bit ModR/M decode. */
switch (c->modrm_rm) {
case 4:
case 12:
if ((c->modrm_rm & 7) == 4) {
sib = insn_fetch(u8, 1, c->eip);
index_reg |= (sib >> 3) & 7;
base_reg |= sib & 7;
@ -754,18 +752,11 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
c->modrm_ea += c->regs[base_reg];
if (index_reg != 4)
c->modrm_ea += c->regs[index_reg] << scale;
break;
case 5:
case 13:
if (c->modrm_mod != 0)
c->modrm_ea += c->regs[c->modrm_rm];
else if (ctxt->mode == X86EMUL_MODE_PROT64)
} else if ((c->modrm_rm & 7) == 5 && c->modrm_mod == 0) {
if (ctxt->mode == X86EMUL_MODE_PROT64)
rip_relative = 1;
break;
default:
} else
c->modrm_ea += c->regs[c->modrm_rm];
break;
}
switch (c->modrm_mod) {
case 0:
if (c->modrm_rm == 5)