Port Math.random change to MIPS.

src/mips/lithium-codegen-mips.cc

Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 06e886c6bb1c9db5aca15deb9a53d43daee24941..7c94730f129a50bc863f27bf129e92f877d11762 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -1,4 +1,4 @@
-// Copyright 2011 the V8 project authors. All rights reserved.
+// Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
@@ -3095,6 +3095,27 @@ void LCodeGen::DoPower(LPower* instr) {
 }
 
 
+void LCodeGen::DoRandom(LRandom* instr) {
+  // Having marked this instruction as a call we can use any
+  // registers.
+  ASSERT(ToDoubleRegister(instr->result()).is(f0));
+  ASSERT(ToRegister(instr->InputAt(0)).is(a0));
+
+  __ PrepareCallCFunction(1, a1);
+  __ lw(a0, FieldMemOperand(a0, GlobalObject::kGlobalContextOffset));
+  __ CallCFunction(ExternalReference::random_uint32_function(isolate()), 1);
+
+  // 0x41300000 is the top half of 1.0 x 2^20 as a double.
+  __ li(a2, Operand(0x41300000));
+  // Move 0x41300000xxxxxxxx (x = random bits in v0) to FPU.
+  __ Move(f12, v0, a2);
+  // Move 0x4130000000000000 to FPU.
+  __ Move(f14, zero_reg, a2);
+  // Subtract to get the result.
+  __ sub_d(f0, f12, f14);
+}
+
+
 void LCodeGen::DoMathLog(LUnaryMathOperation* instr) {
   ASSERT(ToDoubleRegister(instr->result()).is(f4));
   TranscendentalCacheStub stub(TranscendentalCache::LOG,