KVM: x86 emulator: simplify sib decoding

Instead of using sparse switches, use simpler if/else sequences.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 4 insertions, 16 deletions

diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 3721cfddc97..ca7ab2469a4 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -748,24 +748,12 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
                         base_reg |= sib & 7;
                         scale = sib >> 6;
 
-                        switch (base_reg) {
-                        case 5:
-                        case 13:
-                                if (c->modrm_mod != 0)
-                                        c->modrm_ea += c->regs[base_reg];
-                                else
-                                        c->modrm_ea +=
-                                                insn_fetch(s32, 4, c->eip);
-                                break;
-                        default:
+                        if ((base_reg & 7) == 5 && c->modrm_mod == 0)
+                                c->modrm_ea += insn_fetch(s32, 4, c->eip);
+                        else
                                 c->modrm_ea += c->regs[base_reg];
-                        }
-                        switch (index_reg) {
-                        case 4:
-                                break;
-                        default:
+                        if (index_reg != 4)
                                 c->modrm_ea += c->regs[index_reg] << scale;
-                        }
                         break;
                 case 5:
                 case 13: