From: Julian Seward <jseward@acm.org>
Date: Sat, 13 Jul 2002 12:32:16 +0000 (+0000)
Subject: (Tim Rowley, verbatim)
X-Git-Tag: svn/VALGRIND_1_0_3~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=344e4348dee0a22bc9e5e0579c37ff727acf8fa4;p=thirdparty%2Fvalgrind.git

(Tim Rowley, verbatim)

The Intel p4 manual suggests inserting a pause instruction in
spin-wait loops as a hint to what the code is doing.  In other
respects it acts just like a nop.  Pause (0xF3 0x90) currently
causes valgrind to panic.  The patch below keeps things running.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@493
---

diff --git a/coregrind/vg_to_ucode.c b/coregrind/vg_to_ucode.c
index e56b02cab2..0b1e5c61dc 100644
--- a/coregrind/vg_to_ucode.c
+++ b/coregrind/vg_to_ucode.c
@@ -4111,6 +4111,11 @@ static Addr disInstr ( UCodeBlock* cb, Addr eip, Bool* isEnd )
          codegen_REPE_STOS ( cb, sz, eip_orig, eip );
          *isEnd = True;
          if (dis) VG_(printf)("repe stos%c\n", nameISize(sz));
+      }
+      else
+      if (abyte == 0x90) { /* REPE NOP (PAUSE) */
+         if (dis) VG_(printf)("repe nop (P4 pause)\n");
+         /* do nothing; apparently a hint to the P4 re spin-wait loop */
       } else {
          VG_(printf)("REPE then 0x%x\n", (UInt)abyte);
          VG_(panic)("Unhandled REPE case");
diff --git a/vg_to_ucode.c b/vg_to_ucode.c
index e56b02cab2..0b1e5c61dc 100644
--- a/vg_to_ucode.c
+++ b/vg_to_ucode.c
@@ -4111,6 +4111,11 @@ static Addr disInstr ( UCodeBlock* cb, Addr eip, Bool* isEnd )
          codegen_REPE_STOS ( cb, sz, eip_orig, eip );
          *isEnd = True;
          if (dis) VG_(printf)("repe stos%c\n", nameISize(sz));
+      }
+      else
+      if (abyte == 0x90) { /* REPE NOP (PAUSE) */
+         if (dis) VG_(printf)("repe nop (P4 pause)\n");
+         /* do nothing; apparently a hint to the P4 re spin-wait loop */
       } else {
          VG_(printf)("REPE then 0x%x\n", (UInt)abyte);
          VG_(panic)("Unhandled REPE case");