From f05280e4156df2d13d87b1639157c63ed4e3b393 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Fri, 6 May 2016 12:08:00 +0200
Subject: [PATCH] x86/x64: Fix instruction length decoder.

Thanks to Peter Cawley.
---
 src/lj_asm_x86.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/lj_asm_x86.h b/src/lj_asm_x86.h
index 86a5b0a8..02918e23 100644
--- a/src/lj_asm_x86.h
+++ b/src/lj_asm_x86.h
@@ -2836,9 +2836,9 @@ static uint32_t asm_x86_inslen(const uint8_t* p)
     case 4: result -= (prefixes & 2);  /* fallthrough */
     case 5: return result + (x & 15);
     case 6:  /* Group 3. */
-      if (p[1] & 0x38) return result + 2;
-      if ((prefixes & 2) && (x == 0x66)) return result + 4;
-      return result + (x & 15);
+      if (p[1] & 0x38) x = 2;
+      else if ((prefixes & 2) && (x == 0x66)) x = 4;
+      goto mrm;
     case 7: /* VEX c4/c5. */
       if (LJ_32 && p[1] < 0xc0) {
 	x = 2;