Implement Math.random() purely in JavaScript.

src/x64/full-codegen-x64.cc

 // 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:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3228 matching lines @@
     VisitForStackValue(args->at(1));
     VisitForStackValue(args->at(2));
     __ CallRuntime(Runtime::kLog, 2);
   }
   // Finally, we're expected to leave a value on the top of the stack.
   __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
   context()->Plug(rax);
 }
 
 
-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;
   ZoneList<Expression*>* args = expr->arguments();
   ASSERT(args->length() == 3);
   VisitForStackValue(args->at(0));
   VisitForStackValue(args->at(1));
   VisitForStackValue(args->at(2));
   __ CallStub(&stub);
   context()->Plug(rax);
@@ skipping 1651 matching lines @@
 
   ASSERT_EQ(isolate->builtins()->OsrAfterStackCheck()->entry(),
             Assembler::target_address_at(call_target_address));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64