From: Avi Kivity <avi@qumranet.com>
Date: Mon, 16 Jun 2008 04:23:17 +0000 (-0700)
Subject: KVM: x86 emulator: simplify sib decoding
X-Git-Tag: v2.6.27-rc1~968^2~26
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc71d0f1620790ec8e54101ca37e7b31e31208a8;p=linux-2.6

KVM: x86 emulator: simplify sib decoding

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

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

diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 3721cfddc9..ca7ab2469a 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: