[runtime] Implement %_ToLength via ToLengthStub.

src/mips64/code-stubs-mips64.cc

Index: src/mips64/code-stubs-mips64.cc
diff --git a/src/mips64/code-stubs-mips64.cc b/src/mips64/code-stubs-mips64.cc
index d1bdd7d901b7063beb3407d1a3cb7d407df66d37..bb6deb92c2443d508c53546f00df5daf691dbe11 100644
--- a/src/mips64/code-stubs-mips64.cc
+++ b/src/mips64/code-stubs-mips64.cc
@@ -3348,6 +3348,23 @@ void ToNumberStub::Generate(MacroAssembler* masm) {
 }
 
 
+void ToLengthStub::Generate(MacroAssembler* masm) {
+  // The ToLength stub takes on argument in a0.
+  Label not_smi, positive_smi;
+  __ JumpIfNotSmi(a0, &not_smi);
+  STATIC_ASSERT(kSmiTag == 0);
+  __ Branch(&positive_smi, ge, a0, Operand(zero_reg));
+  __ mov(a0, zero_reg);
+  __ bind(&positive_smi);
+  __ Ret(USE_DELAY_SLOT);
+  __ mov(v0, a0);
+  __ bind(&not_smi);
+
+  __ push(a0);  // Push argument.
+  __ TailCallRuntime(Runtime::kToLength, 1, 1);
+}
+
+
 void ToStringStub::Generate(MacroAssembler* masm) {
   // The ToString stub takes on argument in a0.
   Label is_number;