X87: implement MathPow stub for X87.

src/x87/code-stubs-x87.cc

 // Copyright 2012 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 "src/v8.h"
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 307 matching lines @@
   __ mov(scratch, FieldOperand(eax, HeapObject::kMapOffset));
   __ cmp(scratch, factory->heap_number_map());
   __ j(not_equal, non_float);  // argument in eax is not a number -> NaN
 
   // Fall-through: Both operands are numbers.
   __ bind(&done);
 }
 
 
 void MathPowStub::Generate(MacroAssembler* masm) {
-  // No SSE2 support
-  UNREACHABLE();
+  const Register base = edx;
+  const Register scratch = ecx;
+  Counters* counters = isolate()->counters();
+  Label call_runtime;
+
+  // We will call runtime helper function directly.
+  if (exponent_type() == ON_STACK) {
+    // The arguments are still on the stack.
+    __ bind(&call_runtime);
+    __ TailCallRuntime(Runtime::kMathPowRT, 2, 1);
+
+    // The stub is called from non-optimized code, which expects the result
+    // as heap number in exponent.
+    __ AllocateHeapNumber(eax, scratch, base, &call_runtime);
+    __ fstp_d(FieldOperand(eax, HeapNumber::kValueOffset));
+    __ IncrementCounter(counters->math_pow(), 1);
+    __ ret(2 * kPointerSize);
+  } else {
+    // Currently it's only called from full-compiler and exponent type is
+    // ON_STACK.
+    UNIMPLEMENTED();
+  }
 }
 
 
 void FunctionPrototypeStub::Generate(MacroAssembler* masm) {
   Label miss;
   Register receiver = LoadDescriptor::ReceiverRegister();
   // With careful management, we won't have to save slot and vector on
   // the stack. Simply handle the possibly missing case first.
   // TODO(mvstanton): this code can be more efficient.
   __ cmp(FieldOperand(receiver, JSFunction::kPrototypeOrInitialMapOffset),
@@ skipping 4984 matching lines @@
                            Operand(ebp, 7 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87