From: Julian Seward <jseward@acm.org>
Date: Thu, 1 Mar 2007 18:42:07 +0000 (+0000)
Subject: Handle the (bizarre) no-op "26 2E 64 65 90 %es:%cs:%fs:%gs:nop".  This
X-Git-Tag: svn/VALGRIND_3_3_1^2~53
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eb0c38f6dacbf3ee9e7eeb84a2e93b5ab561fe92;p=thirdparty%2Fvalgrind.git

Handle the (bizarre) no-op "26 2E 64 65 90 %es:%cs:%fs:%gs:nop".  This
makes it possible to run Sun's JVM 1.5.0 on Valgrind.



git-svn-id: svn://svn.valgrind.org/vex/trunk@1737
---

diff --git a/VEX/priv/guest-x86/toIR.c b/VEX/priv/guest-x86/toIR.c
index 7a3acf6b32..0b7d0dbe92 100644
--- a/VEX/priv/guest-x86/toIR.c
+++ b/VEX/priv/guest-x86/toIR.c
@@ -7272,6 +7272,18 @@ DisResult disInstr_X86_WRK (
    switch (getIByte(delta)) {
       case 0x3E: /* %DS: */
       case 0x26: /* %ES: */
+         /* Sun's JVM 1.5.0 uses the following as a NOP:
+            26 2E 64 65 90  %es:%cs:%fs:%gs:nop */
+         {
+            UChar* code = (UChar*)(guest_code + delta);
+            if (code[0] == 0x26 && code[1] == 0x2E && code[2] == 0x64 
+                && code[3] == 0x65 && code[4] == 0x90) {
+               DIP("%%es:%%cs:%%fs:%%gs:nop\n");
+               delta += 5;
+               goto decode_success;
+            }
+            /* else fall through */
+         }       
       case 0x64: /* %FS: */
       case 0x65: /* %GS: */
          sorb = getIByte(delta); delta++;