Specialize mint shift code on ia32 for a constant shift amount.

runtime/vm/disassembler_ia32.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/disassembler.h"
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 #include "platform/utils.h"
 #include "vm/allocation.h"
@@ skipping 219 matching lines @@
     case 0x14: return "unpcklps";
     case 0x15: return "unpckhps";
     case 0x16: return "movlhps";
     case 0xA2: return "cpuid";
     case 0x31: return "rdtsc";
     case 0xBE: return "movsx_b";
     case 0xBF: return "movsx_w";
     case 0xB6: return "movzx_b";
     case 0xB7: return "movzx_w";
     case 0xAF: return "imul";
+    case 0xA4:  // Fall through.
     case 0xA5: return "shld";
+    case 0xAC:  // Fall through.
     case 0xAD: return "shrd";
     case 0xAB: return "bts";
     case 0xBD: return "bsr";
     case 0xB1: return "cmpxchg";
     case 0x50: return "movmskps";
     case 0x51: return "sqrtps";
     case 0x52: return "rqstps";
     case 0x53: return "rcpps";
     case 0x54: return "andps";
     case 0x56: return "orps";
@@ skipping 1151 matching lines @@
                      *(data+3) == 0x00 &&
                      *(data+3) == 0x00 &&
                      *(data+4) == 0x00) {
             Print("nop");
             data += 8;
           } else {
             UNIMPLEMENTED();
           }
         } else {
           data += 2;
-          if (f0byte == 0xAB || f0byte == 0xA5 || f0byte == 0xAD) {
+          if (f0byte == 0xAB || f0byte == 0xA4 || f0byte == 0xA5 ||
+              f0byte == 0xAC || f0byte == 0xAD) {
             // shrd, shld, bts
             Print(f0mnem);
             int mod, regop, rm;
             GetModRm(*data, &mod, &regop, &rm);
             Print(" ");
             data += PrintRightOperand(data);
+            Print(",");
+            PrintCPURegister(regop);
             if (f0byte == 0xAB) {
-              Print(",");
-              PrintCPURegister(regop);
+              // Done.
+            } else if (f0byte == 0xA5 || f0byte == 0xAD) {
+              Print(",cl");
             } else {
-              Print(",");
-              PrintCPURegister(regop);
-              Print(",cl");
+              Print(", ");
+              PrintInt(*(data++));
             }
           } else if ((f0byte == 0x10) || (f0byte == 0x11) ||
                      IsTwoXmmRegInstruction(f0byte)) {
             data = SSEInstruction(0x0F, f0byte, data);
           } else if (f0byte == 0x50) {
             Print("movmskps ");
             int mod, regop, rm;
             GetModRm(*data, &mod, &regop, &rm);
             PrintCPURegister(regop);
             Print(",");
@@ skipping 434 matching lines @@
                                   pc);
     pc += instruction_length;
   }
 
   return;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32