Revision: 17632
Author: [email protected]
Date: Tue Nov 12 09:08:51 2013 UTC
Log: Refine CopyBytes macro instruction in IA32/X64
Use DWORD/QWORD copy for more short cases
BUG=
[email protected]
Review URL: https://codereview.chromium.org/66073003
Patch from Weiliang Lin <[email protected]>.
http://code.google.com/p/v8/source/detail?r=17632
Modified:
/branches/bleeding_edge/src/ia32/macro-assembler-ia32.cc
/branches/bleeding_edge/src/x64/macro-assembler-x64.cc
=======================================
--- /branches/bleeding_edge/src/ia32/macro-assembler-ia32.cc Fri Nov 8
17:35:58 2013 UTC
+++ /branches/bleeding_edge/src/ia32/macro-assembler-ia32.cc Tue Nov 12
09:08:51 2013 UTC
@@ -2010,30 +2010,48 @@
Register destination,
Register length,
Register scratch) {
- Label loop, done, short_string, short_loop;
- // Experimentation shows that the short string loop is faster if length
< 10.
- cmp(length, Immediate(10));
- j(less_equal, &short_string);
-
+ Label short_loop, len4, len8, len12, done, short_string;
ASSERT(source.is(esi));
ASSERT(destination.is(edi));
ASSERT(length.is(ecx));
+ cmp(length, Immediate(4));
+ j(below, &short_string, Label::kNear);
// Because source is 4-byte aligned in our uses of this function,
// we keep source aligned for the rep_movs call by copying the odd bytes
// at the end of the ranges.
mov(scratch, Operand(source, length, times_1, -4));
mov(Operand(destination, length, times_1, -4), scratch);
+
+ cmp(length, Immediate(8));
+ j(below_equal, &len4, Label::kNear);
+ cmp(length, Immediate(12));
+ j(below_equal, &len8, Label::kNear);
+ cmp(length, Immediate(16));
+ j(below_equal, &len12, Label::kNear);
+
mov(scratch, ecx);
shr(ecx, 2);
rep_movs();
and_(scratch, Immediate(0x3));
add(destination, scratch);
- jmp(&done);
+ jmp(&done, Label::kNear);
+
+ bind(&len12);
+ mov(scratch, Operand(source, 8));
+ mov(Operand(destination, 8), scratch);
+ bind(&len8);
+ mov(scratch, Operand(source, 4));
+ mov(Operand(destination, 4), scratch);
+ bind(&len4);
+ mov(scratch, Operand(source, 0));
+ mov(Operand(destination, 0), scratch);
+ add(destination, length);
+ jmp(&done, Label::kNear);
bind(&short_string);
test(length, length);
- j(zero, &done);
+ j(zero, &done, Label::kNear);
bind(&short_loop);
mov_b(scratch, Operand(source, 0));
=======================================
--- /branches/bleeding_edge/src/x64/macro-assembler-x64.cc Mon Nov 11
18:00:52 2013 UTC
+++ /branches/bleeding_edge/src/x64/macro-assembler-x64.cc Tue Nov 12
09:08:51 2013 UTC
@@ -4415,18 +4415,27 @@
cmpl(length, Immediate(min_length));
Assert(greater_equal, kInvalidMinLength);
}
- Label loop, done, short_string, short_loop;
+ Label short_loop, len8, len16, len24, done, short_string;
- const int kLongStringLimit = 20;
+ const int kLongStringLimit = 4 * kPointerSize;
if (min_length <= kLongStringLimit) {
- cmpl(length, Immediate(kLongStringLimit));
- j(less_equal, &short_string);
+ cmpl(length, Immediate(kPointerSize));
+ j(below, &short_string, Label::kNear);
}
ASSERT(source.is(rsi));
ASSERT(destination.is(rdi));
ASSERT(length.is(rcx));
+ if (min_length <= kLongStringLimit) {
+ cmpl(length, Immediate(2 * kPointerSize));
+ j(below_equal, &len8, Label::kNear);
+ cmpl(length, Immediate(3 * kPointerSize));
+ j(below_equal, &len16, Label::kNear);
+ cmpl(length, Immediate(4 * kPointerSize));
+ j(below_equal, &len24, Label::kNear);
+ }
+
// Because source is 8-byte aligned in our uses of this function,
// we keep source aligned for the rep movs operation by copying the odd
bytes
// at the end of the ranges.
@@ -4440,25 +4449,38 @@
addq(destination, scratch);
if (min_length <= kLongStringLimit) {
- jmp(&done);
+ jmp(&done, Label::kNear);
+ bind(&len24);
+ movq(scratch, Operand(source, 2 * kPointerSize));
+ movq(Operand(destination, 2 * kPointerSize), scratch);
+ bind(&len16);
+ movq(scratch, Operand(source, kPointerSize));
+ movq(Operand(destination, kPointerSize), scratch);
+ bind(&len8);
+ movq(scratch, Operand(source, 0));
+ movq(Operand(destination, 0), scratch);
+ // Move remaining bytes of length.
+ movq(scratch, Operand(source, length, times_1, -kPointerSize));
+ movq(Operand(destination, length, times_1, -kPointerSize), scratch);
+ addq(destination, length);
+ jmp(&done, Label::kNear);
bind(&short_string);
if (min_length == 0) {
testl(length, length);
- j(zero, &done);
+ j(zero, &done, Label::kNear);
}
- lea(scratch, Operand(destination, length, times_1, 0));
bind(&short_loop);
- movb(length, Operand(source, 0));
- movb(Operand(destination, 0), length);
+ movb(scratch, Operand(source, 0));
+ movb(Operand(destination, 0), scratch);
incq(source);
incq(destination);
- cmpq(destination, scratch);
- j(not_equal, &short_loop);
+ decl(length);
+ j(not_zero, &short_loop);
+ }
- bind(&done);
- }
+ bind(&done);
}
--
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