Revision: 16976
Author: [email protected]
Date: Fri Sep 27 07:46:52 2013 UTC
Log: Tweak SmiSub for X64
[email protected]
Review URL: https://codereview.chromium.org/24965002
http://code.google.com/p/v8/source/detail?r=16976
Modified:
/branches/bleeding_edge/src/x64/macro-assembler-x64.cc
/branches/bleeding_edge/src/x64/macro-assembler-x64.h
=======================================
--- /branches/bleeding_edge/src/x64/macro-assembler-x64.cc Thu Sep 19
06:07:23 2013 UTC
+++ /branches/bleeding_edge/src/x64/macro-assembler-x64.cc Fri Sep 27
07:46:52 2013 UTC
@@ -1697,6 +1697,29 @@
Assert(no_overflow, kSmiAdditionOverflow);
}
}
+
+
+template<class T>
+static void SmiSubHelper(MacroAssembler* masm,
+ Register dst,
+ Register src1,
+ T src2,
+ Label* on_not_smi_result,
+ Label::Distance near_jump) {
+ if (dst.is(src1)) {
+ Label done;
+ masm->subq(dst, src2);
+ masm->j(no_overflow, &done, Label::kNear);
+ // Restore src1.
+ masm->addq(dst, src2);
+ masm->jmp(on_not_smi_result, near_jump);
+ masm->bind(&done);
+ } else {
+ masm->movq(dst, src1);
+ masm->subq(dst, src2);
+ masm->j(overflow, on_not_smi_result, near_jump);
+ }
+}
void MacroAssembler::SmiSub(Register dst,
@@ -1706,27 +1729,7 @@
Label::Distance near_jump) {
ASSERT_NOT_NULL(on_not_smi_result);
ASSERT(!dst.is(src2));
- if (dst.is(src1)) {
- cmpq(dst, src2);
- j(overflow, on_not_smi_result, near_jump);
- subq(dst, src2);
- } else {
- movq(dst, src1);
- subq(dst, src2);
- j(overflow, on_not_smi_result, near_jump);
- }
-}
-
-
-void MacroAssembler::SmiSub(Register dst, Register src1, Register src2) {
- // No overflow checking. Use only when it's known that
- // overflowing is impossible (e.g., subtracting two positive smis).
- ASSERT(!dst.is(src2));
- if (!dst.is(src1)) {
- movq(dst, src1);
- }
- subq(dst, src2);
- Assert(no_overflow, kSmiSubtractionOverflow);
+ SmiSubHelper<Register>(this, dst, src1, src2, on_not_smi_result,
near_jump);
}
@@ -1736,29 +1739,36 @@
Label* on_not_smi_result,
Label::Distance near_jump) {
ASSERT_NOT_NULL(on_not_smi_result);
- if (dst.is(src1)) {
- movq(kScratchRegister, src2);
- cmpq(src1, kScratchRegister);
- j(overflow, on_not_smi_result, near_jump);
- subq(src1, kScratchRegister);
- } else {
- movq(dst, src1);
- subq(dst, src2);
- j(overflow, on_not_smi_result, near_jump);
+ ASSERT(!src2.AddressUsesRegister(dst));
+ SmiSubHelper<Operand>(this, dst, src1, src2, on_not_smi_result,
near_jump);
+}
+
+
+template<class T>
+static void SmiSubNoOverflowHelper(MacroAssembler* masm,
+ Register dst,
+ Register src1,
+ T src2) {
+ // No overflow checking. Use only when it's known that
+ // overflowing is impossible (e.g., subtracting two positive smis).
+ if (!dst.is(src1)) {
+ masm->movq(dst, src1);
}
+ masm->subq(dst, src2);
+ masm->Assert(no_overflow, kSmiSubtractionOverflow);
+}
+
+
+void MacroAssembler::SmiSub(Register dst, Register src1, Register src2) {
+ ASSERT(!dst.is(src2));
+ SmiSubNoOverflowHelper<Register>(this, dst, src1, src2);
}
void MacroAssembler::SmiSub(Register dst,
Register src1,
const Operand& src2) {
- // No overflow checking. Use only when it's known that
- // overflowing is impossible (e.g., subtracting two positive smis).
- if (!dst.is(src1)) {
- movq(dst, src1);
- }
- subq(dst, src2);
- Assert(no_overflow, kSmiSubtractionOverflow);
+ SmiSubNoOverflowHelper<Operand>(this, dst, src1, src2);
}
=======================================
--- /branches/bleeding_edge/src/x64/macro-assembler-x64.h Thu Sep 19
06:07:23 2013 UTC
+++ /branches/bleeding_edge/src/x64/macro-assembler-x64.h Fri Sep 27
07:46:52 2013 UTC
@@ -596,23 +596,22 @@
Register src2);
// Subtracts smi values and return the result as a smi.
- // If dst is src1, then src1 will be destroyed, even if
- // the operation is unsuccessful.
+ // If dst is src1, then src1 will be destroyed if the operation is
+ // successful, otherwise kept intact.
void SmiSub(Register dst,
Register src1,
Register src2,
Label* on_not_smi_result,
Label::Distance near_jump = Label::kFar);
-
void SmiSub(Register dst,
Register src1,
- Register src2);
+ const Operand& src2,
+ Label* on_not_smi_result,
+ Label::Distance near_jump = Label::kFar);
void SmiSub(Register dst,
Register src1,
- const Operand& src2,
- Label* on_not_smi_result,
- Label::Distance near_jump = Label::kFar);
+ Register src2);
void SmiSub(Register dst,
Register src1,
--
--
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