MIPS64: Improve long branches utilizing code range.

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>
 
 #include "src/v8.h"
@@ skipping 3905 matching lines @@
   // If needed update pc after the branch delay execution.
   if (next_pc != bad_ra) {
     set_pc(next_pc);
   }
 }
 
 
 // Type 3: instructions using a 26 bytes immediate. (e.g. j, jal).
 void Simulator::DecodeTypeJump(Instruction* instr) {
   // Get current pc.
-  int32_t current_pc = get_pc();
+  int64_t current_pc = get_pc();
   // Get unchanged bits of pc.
-  int32_t pc_high_bits = current_pc & 0xf0000000;
+  int64_t pc_high_bits = current_pc & 0xfffffffff0000000;
   // Next pc.
-  int32_t next_pc = pc_high_bits | (instr->Imm26Value() << 2);
+  int64_t next_pc = pc_high_bits | (instr->Imm26Value() << 2);
 
   // Execute branch delay slot.
   // We don't check for end_sim_pc. First it should not be met as the current pc
   // is valid. Secondly a jump should always execute its branch delay slot.
   Instruction* branch_delay_instr =
       reinterpret_cast<Instruction*>(current_pc + Instruction::kInstrSize);
   BranchDelayInstructionDecode(branch_delay_instr);
 
   // Update pc and ra if necessary.
   // Do this after the branch delay execution.
@@ skipping 239 matching lines @@
   return address;
 }
 
 
 #undef UNSUPPORTED
 } }  // namespace v8::internal
 
 #endif  // USE_SIMULATOR
 
 #endif  // V8_TARGET_ARCH_MIPS64