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authorBandan Das <bsd@redhat.com>2014-04-16 12:46:11 -0400
committerPaolo Bonzini <pbonzini@redhat.com>2014-07-11 09:14:00 +0200
commit02357bdc8c30a60cd33dd438f851c1306c34f435 (patch)
treed74663db7274e8e387554d0373d0c844b96ddba2 /arch/x86/kvm
parent685bbf4ac406364a84a1d4237b4970dc570fd4cb (diff)
downloadlinux-02357bdc8c30a60cd33dd438f851c1306c34f435.tar.gz
KVM: emulate: cleanup decode_modrm
Remove the if conditional - that will help us avoid an "else initialize to 0" Also, rearrange operators for slightly better code. Signed-off-by: Bandan Das <bsd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/emulate.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 000fc739883..94f5f8b94ce 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1066,19 +1066,17 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
struct operand *op)
{
u8 sib;
- int index_reg = 0, base_reg = 0, scale;
+ int index_reg, base_reg, scale;
int rc = X86EMUL_CONTINUE;
ulong modrm_ea = 0;
- if (ctxt->rex_prefix) {
- ctxt->modrm_reg = (ctxt->rex_prefix & 4) << 1; /* REX.R */
- index_reg = (ctxt->rex_prefix & 2) << 2; /* REX.X */
- ctxt->modrm_rm = base_reg = (ctxt->rex_prefix & 1) << 3; /* REG.B */
- }
+ ctxt->modrm_reg = ((ctxt->rex_prefix << 1) & 8); /* REX.R */
+ index_reg = (ctxt->rex_prefix << 2) & 8; /* REX.X */
+ base_reg = (ctxt->rex_prefix << 3) & 8; /* REX.B */
- ctxt->modrm_mod |= (ctxt->modrm & 0xc0) >> 6;
+ ctxt->modrm_mod = (ctxt->modrm & 0xc0) >> 6;
ctxt->modrm_reg |= (ctxt->modrm & 0x38) >> 3;
- ctxt->modrm_rm |= (ctxt->modrm & 0x07);
+ ctxt->modrm_rm = base_reg | (ctxt->modrm & 0x07);
ctxt->modrm_seg = VCPU_SREG_DS;
if (ctxt->modrm_mod == 3 || (ctxt->d & NoMod)) {