MIPS64: Fix code generator and simulator for DEXTM.

src/mips64/simulator-mips64.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 <limits.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <cmath>
 
 #if V8_TARGET_ARCH_MIPS64
@@ skipping 4054 matching lines @@
       alu_out = static_cast<int32_t>((rs_u() & (mask << lsb)) >> lsb);
       SetResult(rt_reg(), alu_out);
       break;
     }
     case DEXT: {  // Mips64r2 instruction.
       // Interpret rd field as 5-bit msb of extract.
       uint16_t msb = rd_reg();
       // Interpret sa field as 5-bit lsb of extract.
       uint16_t lsb = sa();
       uint16_t size = msb + 1;
-      uint64_t mask = (1ULL << size) - 1;
+      uint64_t mask = (size == 64) ? UINT64_MAX : (1ULL << size) - 1;
       alu_out = static_cast<int64_t>((rs_u() & (mask << lsb)) >> lsb);
       SetResult(rt_reg(), alu_out);
       break;
     }
     case DEXTM: {
       // Interpret rd field as 5-bit msb of extract.
       uint16_t msb = rd_reg();
       // Interpret sa field as 5-bit lsb of extract.
       uint16_t lsb = sa();
       uint16_t size = msb + 33;
-      uint64_t mask = (1ULL << size) - 1;
+      uint64_t mask = (size == 64) ? UINT64_MAX : (1ULL << size) - 1;
       alu_out = static_cast<int64_t>((rs_u() & (mask << lsb)) >> lsb);
       SetResult(rt_reg(), alu_out);
       break;
     }
     case DEXTU: {
       // Interpret rd field as 5-bit msb of extract.
       uint16_t msb = rd_reg();
       // Interpret sa field as 5-bit lsb of extract.
       uint16_t lsb = sa() + 32;
       uint16_t size = msb + 1;
-      uint64_t mask = (1ULL << size) - 1;
+      uint64_t mask = (size == 64) ? UINT64_MAX : (1ULL << size) - 1;
       alu_out = static_cast<int64_t>((rs_u() & (mask << lsb)) >> lsb);
       SetResult(rt_reg(), alu_out);
       break;
     }
     case BSHFL: {
       int32_t sa = instr_.SaFieldRaw() >> kSaShift;
       switch (sa) {
         case BITSWAP: {
           uint32_t input = static_cast<uint32_t>(rt());
           uint32_t output = 0;
@@ skipping 1035 matching lines @@
 }
 
 
 #undef UNSUPPORTED
 }  // namespace internal
 }  // namespace v8
 
 #endif  // USE_SIMULATOR
 
 #endif  // V8_TARGET_ARCH_MIPS64