Fix testing of the VEX.L (128/256-bit) flag in the x64 disassembler

src/ia32/disasm-ia32.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <assert.h>
 #include <stdarg.h>
 #include <stdio.h>
 
 #if V8_TARGET_ARCH_IA32
 
@@ skipping 263 matching lines @@
     kRCL = 2,
     kRCR = 3,
     kSHL = 4,
     KSHR = 5,
     kSAR = 7
   };
 
   bool vex_128() {
     DCHECK(vex_byte0_ == 0xc4 || vex_byte0_ == 0xc5);
     byte checked = vex_byte0_ == 0xc4 ? vex_byte2_ : vex_byte1_;
-    return (checked & 4) != 1;
+    return (checked & 4) == 0;
   }
 
   bool vex_none() {
     DCHECK(vex_byte0_ == 0xc4 || vex_byte0_ == 0xc5);
     byte checked = vex_byte0_ == 0xc4 ? vex_byte2_ : vex_byte1_;
     return (checked & 3) == 0;
   }
 
   bool vex_66() {
     DCHECK(vex_byte0_ == 0xc4 || vex_byte0_ == 0xc5);
@@ skipping 1984 matching lines @@
       fprintf(f, "  ");
     }
     fprintf(f, "  %s\n", buffer.start());
   }
 }
 
 
 }  // namespace disasm
 
 #endif  // V8_TARGET_ARCH_IA32