Instruction prefixes can appear in any order.


 coregrind/vg_to_ucode.c |   49 ++++++++++++++++++++++++++++--------------------
 1 files changed, 29 insertions(+), 20 deletions(-)

diff -puN coregrind/vg_to_ucode.c~fix-prefixes coregrind/vg_to_ucode.c
--- valgrind/coregrind/vg_to_ucode.c~fix-prefixes	2005-01-10 16:40:48.000000000 -0800
+++ valgrind-jeremy/coregrind/vg_to_ucode.c	2005-01-10 16:40:48.000000000 -0800
@@ -3859,6 +3859,7 @@ static Addr disInstr ( UCodeBlock* cb, A
    UChar dis_buf[50];
    Int   am_sz, d_sz;
    static Char  loc_buf[M_VG_ERRTXT];
+   Bool  done;
 
    /* Holds eip at the start of the insn, so that we can print
       consistent error messages for unimplemented insns. */
@@ -3906,25 +3907,28 @@ static Addr disInstr ( UCodeBlock* cb, A
       }
    }
 
-   /* Skip a LOCK prefix. */
-   if (getUChar(eip) == 0xF0) { 
-      /* VG_(printf)("LOCK LOCK LOCK LOCK LOCK \n"); */
-      uInstr0(cb, LOCK, 0);
-      eip++;
-   }
+   /* There can be any number of prefixes in any order */
+   for(done = False; !done;) {
+      switch (getUChar(eip)) {
+      case 0xf0:		/* LOCK */
+	 /* Skip a LOCK prefix. */
+	 /* VG_(printf)("LOCK LOCK LOCK LOCK LOCK \n"); */
+	 eip++;
+	 break;
+
+      case 0x66:		/* operand size */
+	 sz = 2;
+	 eip++;
+	 break;
 
-   /* Detect operand-size overrides. */
-   if (getUChar(eip) == 0x66) { sz = 2; eip++; };
-
-   /* segment override prefixes come after the operand-size override,
-      it seems */
-   switch (getUChar(eip)) {
+      /* Segment overrides */
       case 0x3E: /* %DS: */
       case 0x26: /* %ES: */
       case 0x64: /* %FS: */
       case 0x65: /* %GS: */
          sorb = getUChar(eip); eip++; 
          break;
+
       case 0x2E: /* %CS: */
          /* 2E prefix on a conditional branch instruction is a
             branch-prediction hint, which can safely be ignored.  */
@@ -3945,8 +3949,12 @@ static Addr disInstr ( UCodeBlock* cb, A
          VG_(unimplemented)("x86 segment override (SEG=SS) prefix");
          /*NOTREACHED*/
          break;
+
       default:
-         break;
+	 done = True;
+	 break;
+
+      }
    }
 
    /* ---------------------------------------------------- */
@@ -7319,16 +7327,17 @@ static Addr disInstr ( UCodeBlock* cb, A
   default:
   decode_failure:
    /* All decode failures end up here. */
-   VG_(printf)("disInstr: unhandled instruction bytes: "
-               "0x%x 0x%x 0x%x 0x%x\n",
-               (Int)eip_start[0],
-               (Int)eip_start[1],
-               (Int)eip_start[2],
-               (Int)eip_start[3] );
+     VG_(message)(Vg_DebugMsg, 
+		  "disInstr: unhandled instruction bytes: "
+		  "0x%x 0x%x 0x%x 0x%x",
+		  (Int)eip_start[0],
+		  (Int)eip_start[1],
+		  (Int)eip_start[2],
+		  (Int)eip_start[3] );
 
    /* Print address of failing instruction. */
    VG_(describe_eip)((Addr)eip_start, loc_buf, M_VG_ERRTXT);
-   VG_(printf)("          at %s\n", loc_buf);
+   VG_(message)(Vg_DebugMsg, "          at %s", loc_buf);
 
    uInstr0(cb, CALLM_S, 0);
    uInstr1(cb, CALLM,   0, Lit16, 

_