Implement Math.random() purely in JavaScript.

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index d5fa5e5a7ca250543ce1645959151350f0b102cf..b0472846bdc157dbb009988286f11f4ef81e5b99 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -3273,47 +3273,6 @@ void FullCodeGenerator::EmitLog(CallRuntime* expr) {
 }
 
 
-void FullCodeGenerator::EmitRandomHeapNumber(CallRuntime* expr) {
-  ASSERT(expr->arguments()->length() == 0);
-
-  Label slow_allocate_heapnumber;
-  Label heapnumber_allocated;
-
-  __ AllocateHeapNumber(rbx, rcx, &slow_allocate_heapnumber);
-  __ jmp(&heapnumber_allocated);
-
-  __ bind(&slow_allocate_heapnumber);
-  // Allocate a heap number.
-  __ CallRuntime(Runtime::kNumberAlloc, 0);
-  __ movq(rbx, rax);
-
-  __ bind(&heapnumber_allocated);
-
-  // Return a random uint32 number in rax.
-  // The fresh HeapNumber is in rbx, which is callee-save on both x64 ABIs.
-  __ PrepareCallCFunction(1);
-  __ movq(arg_reg_1,
-          ContextOperand(context_register(), Context::GLOBAL_OBJECT_INDEX));
-  __ movq(arg_reg_1,
-          FieldOperand(arg_reg_1, GlobalObject::kNativeContextOffset));
-  __ CallCFunction(ExternalReference::random_uint32_function(isolate()), 1);
-
-  // Convert 32 random bits in rax to 0.(32 random bits) in a double
-  // by computing:
-  // ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
-  __ movl(rcx, Immediate(0x49800000));  // 1.0 x 2^20 as single.
-  __ movd(xmm1, rcx);
-  __ movd(xmm0, rax);
-  __ cvtss2sd(xmm1, xmm1);
-  __ xorps(xmm0, xmm1);
-  __ subsd(xmm0, xmm1);
-  __ movsd(FieldOperand(rbx, HeapNumber::kValueOffset), xmm0);
-
-  __ movq(rax, rbx);
-  context()->Plug(rax);
-}
-
-
 void FullCodeGenerator::EmitSubString(CallRuntime* expr) {
   // Load the arguments on the stack and call the stub.
   SubStringStub stub;