Author: [email protected]
Date: Fri Feb 20 06:23:54 2009
New Revision: 1331
Modified:
branches/bleeding_edge/src/codegen-ia32.cc
Log:
Simplify non-smi bit operation optimization. The explicit range
checks are not needed. If we fail to store the float as a 64-bit
integer, we just go to the runtime system. The only extra case in
which we enter the runtime system is for NaN which should not matter.
Review URL: http://codereview.chromium.org/21539
Modified: branches/bleeding_edge/src/codegen-ia32.cc
==============================================================================
--- branches/bleeding_edge/src/codegen-ia32.cc (original)
+++ branches/bleeding_edge/src/codegen-ia32.cc Fri Feb 20 06:23:54 2009
@@ -4482,57 +4482,23 @@
FloatingPointHelper::CheckFloatOperands(masm, &call_runtime, ebx);
FloatingPointHelper::LoadFloatOperands(masm, ecx);
- Label non_smi_result, skip_allocation, operands_too_large;
-
- // Make sure that the operands can be truncated into 64-bit
- // integers. Otherwise, the fistt instruction will signal an IA
- // exception which will cause us to overwrite the operand with
- // zero.
- __ push(Immediate(0x7fffffff));
- __ push(Immediate(-1));
- __ fild_d(Operand(esp, 0));
- __ add(Operand(esp), Immediate(2 * kPointerSize));
-
- // Convert the operands to absolute values before comparing
- // against the limit.
- __ fld(2);
- __ fabs();
- __ fld(2);
- __ fabs();
-
- // Do the comparison. If the operands are too large we go
- // slow-case through the runtime system.
- __ fucomp(2);
- __ fnstsw_ax();
- __ sahf();
- __ j(above, &operands_too_large);
- __ fucompp();
- __ fnstsw_ax();
- __ sahf();
- __ j(above, &operands_too_large);
+ Label non_smi_result, skip_allocation, operands_failed_conversion;
// Reserve space for converted numbers.
__ sub(Operand(esp), Immediate(4 * kPointerSize));
// Convert right operand to int32.
- Label done_right;
__ fnclex();
__ fisttp_d(Operand(esp, 2 * kPointerSize));
__ fnstsw_ax();
__ test(eax, Immediate(1));
- __ j(zero, &done_right);
- __ fnclex();
- __ mov(Operand(esp, 2 * kPointerSize), Immediate(0));
- __ bind(&done_right);
+ __ j(not_zero, &operands_failed_conversion);
// Convert left operand to int32.
- Label done_left;
__ fisttp_d(Operand(esp, 0 * kPointerSize));
__ fnstsw_ax();
__ test(eax, Immediate(1));
- __ j(zero, &done_left);
- __ mov(Operand(esp, 0 * kPointerSize), Immediate(0));
- __ bind(&done_left);
+ __ j(not_zero, &operands_failed_conversion);
// Get int32 operands and perform bitop.
__ pop(eax);
@@ -4587,10 +4553,10 @@
__ ret(2 * kPointerSize);
}
- // Free ST(0) and ST(1) before calling runtime.
- __ bind(&operands_too_large);
+ // Free ST(0) before calling runtime.
+ __ bind(&operands_failed_conversion);
+ __ add(Operand(esp), Immediate(4 * kPointerSize));
__ ffree(0);
- __ ffree(1);
// SHR should return uint32 - go to runtime for non-smi/negative
result.
if (op_ == Token::SHR) __ bind(&non_smi_result);
--~--~---------~--~----~------------~-------~--~----~
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
-~----------~----~----~----~------~----~------~--~---
