}
-// -------------------------------------------------------------------------
-// StringCharAtGenerator
-
-void StringCharAtGenerator::GenerateFast(MacroAssembler* masm) {
- char_code_at_generator_.GenerateFast(masm);
- char_from_code_generator_.GenerateFast(masm);
-}
-
-
-void StringCharAtGenerator::GenerateSlow(
- MacroAssembler* masm,
- const RuntimeCallHelper& call_helper) {
- char_code_at_generator_.GenerateSlow(masm, call_helper);
- char_from_code_generator_.GenerateSlow(masm, call_helper);
-}
-
-
void StringHelper::GenerateCopyCharacters(MacroAssembler* masm,
Register dest,
Register src,
__ Branch(&runtime, ne, t0, Operand(zero_reg));
+ Label single_char;
+ __ Branch(&single_char, eq, a2, Operand(1));
+
// Short-cut for the case of trivial substring.
Label return_v0;
// v0: original string
// Just jump to runtime to create the sub string.
__ bind(&runtime);
__ TailCallRuntime(Runtime::kSubString, 3, 1);
+
+ __ bind(&single_char);
+ // v0: original string
+ // a1: instance type
+ // a2: length
+ // a3: from index (untagged)
+ __ SmiTag(a3, a3);
+ StringCharAtGenerator generator(
+ v0, a3, a2, v0, &runtime, &runtime, &runtime, STRING_INDEX_IS_NUMBER);
+ generator.GenerateFast(masm);
+ __ DropAndRet(3);
+ generator.SkipSlow(masm, &runtime);
}