Revision: 13396
Author: [email protected]
Date: Wed Jan 16 03:45:08 2013
Log: Revert "Optimize the emitted instruction of random function for
X64"
This reverts r13393.
Review URL: https://codereview.chromium.org/11967009
http://code.google.com/p/v8/source/detail?r=13396
Modified:
/branches/bleeding_edge/src/x64/assembler-x64.cc
/branches/bleeding_edge/src/x64/assembler-x64.h
/branches/bleeding_edge/src/x64/lithium-codegen-x64.cc
=======================================
--- /branches/bleeding_edge/src/x64/assembler-x64.cc Wed Jan 16 02:35:24
2013
+++ /branches/bleeding_edge/src/x64/assembler-x64.cc Wed Jan 16 03:45:08
2013
@@ -1644,15 +1644,6 @@
emit(0xB7);
emit_operand(dst, src);
}
-
-
-void Assembler::movzxwl(Register dst, Register src) {
- EnsureSpace ensure_space(this);
- emit_optional_rex_32(dst, src);
- emit(0x0F);
- emit(0xB7);
- emit_modrm(dst, src);
-}
void Assembler::repmovsb() {
=======================================
--- /branches/bleeding_edge/src/x64/assembler-x64.h Wed Jan 16 02:35:24 2013
+++ /branches/bleeding_edge/src/x64/assembler-x64.h Wed Jan 16 03:45:08 2013
@@ -732,7 +732,6 @@
void movzxbl(Register dst, const Operand& src);
void movzxwq(Register dst, const Operand& src);
void movzxwl(Register dst, const Operand& src);
- void movzxwl(Register dst, Register src);
// Repeated moves.
=======================================
--- /branches/bleeding_edge/src/x64/lithium-codegen-x64.cc Wed Jan 16
02:35:24 2013
+++ /branches/bleeding_edge/src/x64/lithium-codegen-x64.cc Wed Jan 16
03:45:08 2013
@@ -3594,43 +3594,45 @@
// rbx: FixedArray of the native context's random seeds
// Load state[0].
- __ movl(rcx, FieldOperand(rbx, ByteArray::kHeaderSize));
+ __ movl(rax, FieldOperand(rbx, ByteArray::kHeaderSize));
// If state[0] == 0, call runtime to initialize seeds.
- __ testl(rcx, rcx);
+ __ testl(rax, rax);
__ j(zero, deferred->entry());
// Load state[1].
- __ movl(rax, FieldOperand(rbx, ByteArray::kHeaderSize + kSeedSize));
+ __ movl(rcx, FieldOperand(rbx, ByteArray::kHeaderSize + kSeedSize));
// state[0] = 18273 * (state[0] & 0xFFFF) + (state[0] >> 16)
- // Only operate on the lower 32 bit of rcx.
- __ movzxwl(rdx, rcx);
+ // Only operate on the lower 32 bit of rax.
+ __ movl(rdx, rax);
+ __ andl(rdx, Immediate(0xFFFF));
__ imull(rdx, rdx, Immediate(18273));
- __ shrl(rcx, Immediate(16));
- __ addl(rcx, rdx);
+ __ shrl(rax, Immediate(16));
+ __ addl(rax, rdx);
// Save state[0].
- __ movl(FieldOperand(rbx, ByteArray::kHeaderSize), rcx);
+ __ movl(FieldOperand(rbx, ByteArray::kHeaderSize), rax);
// state[1] = 36969 * (state[1] & 0xFFFF) + (state[1] >> 16)
- __ movzxwl(rdx, rax);
+ __ movl(rdx, rcx);
+ __ andl(rdx, Immediate(0xFFFF));
__ imull(rdx, rdx, Immediate(36969));
- __ shrl(rax, Immediate(16));
- __ addl(rax, rdx);
+ __ shrl(rcx, Immediate(16));
+ __ addl(rcx, rdx);
// Save state[1].
- __ movl(FieldOperand(rbx, ByteArray::kHeaderSize + kSeedSize), rax);
+ __ movl(FieldOperand(rbx, ByteArray::kHeaderSize + kSeedSize), rcx);
// Random bit pattern = (state[0] << 14) + (state[1] & 0x3FFFF)
- __ shll(rcx, Immediate(14));
- __ andl(rax, Immediate(0x3FFFF));
- __ addl(rcx, rax);
+ __ shll(rax, Immediate(14));
+ __ andl(rcx, Immediate(0x3FFFF));
+ __ addl(rax, rcx);
__ bind(deferred->exit());
- // Convert 32 random bits in rcx to 0.(32 random bits) in a double
+ // Convert 32 random bits in rax to 0.(32 random bits) in a double
// by computing:
// ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
- __ movq(rax, V8_INT64_C(0x4130000000000000),
- RelocInfo::NONE64); // 1.0 x 2^20 as double
- __ movq(xmm2, rax);
- __ movd(xmm1, rcx);
+ __ movl(rcx, Immediate(0x49800000)); // 1.0 x 2^20 as single.
+ __ movd(xmm2, rcx);
+ __ movd(xmm1, rax);
+ __ cvtss2sd(xmm2, xmm2);
__ xorps(xmm1, xmm2);
__ subsd(xmm1, xmm2);
}
--
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