MIPS64: Improve long branches utilizing code range.

src/mips64/simulator-mips64.cc

Index: src/mips64/simulator-mips64.cc
diff --git a/src/mips64/simulator-mips64.cc b/src/mips64/simulator-mips64.cc
index 4298ca0e16cda9f61e8a10293278a910c2f0cea8..254d4f6fb27c3925c99c2b641591f223a63d67f7 100644
--- a/src/mips64/simulator-mips64.cc
+++ b/src/mips64/simulator-mips64.cc
@@ -3923,11 +3923,11 @@ void Simulator::DecodeTypeImmediate(Instruction* instr) {
 // 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