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| // Copyright 2014 The Go Authors. All rights reserved.
| // Use of this source code is governed by a BSD-style
| // license that can be found in the LICENSE file.
|
| // +build !plan9
|
| #include "go_asm.h"
| #include "textflag.h"
|
| // NOTE: Windows externalthreadhandler expects memclr to preserve DX.
|
| // func memclrNoHeapPointers(ptr unsafe.Pointer, n uintptr)
| TEXT runtime·memclrNoHeapPointers(SB), NOSPLIT, $0-8
| MOVL ptr+0(FP), DI
| MOVL n+4(FP), BX
| XORL AX, AX
|
| // MOVOU seems always faster than REP STOSL.
| tail:
| // BSR+branch table make almost all memmove/memclr benchmarks worse. Not worth doing.
| TESTL BX, BX
| JEQ _0
| CMPL BX, $2
| JBE _1or2
| CMPL BX, $4
| JB _3
| JE _4
| CMPL BX, $8
| JBE _5through8
| CMPL BX, $16
| JBE _9through16
| CMPB internal∕cpu·X86+const_offsetX86HasSSE2(SB), $1
| JNE nosse2
| PXOR X0, X0
| CMPL BX, $32
| JBE _17through32
| CMPL BX, $64
| JBE _33through64
| CMPL BX, $128
| JBE _65through128
| CMPL BX, $256
| JBE _129through256
|
| loop:
| MOVOU X0, 0(DI)
| MOVOU X0, 16(DI)
| MOVOU X0, 32(DI)
| MOVOU X0, 48(DI)
| MOVOU X0, 64(DI)
| MOVOU X0, 80(DI)
| MOVOU X0, 96(DI)
| MOVOU X0, 112(DI)
| MOVOU X0, 128(DI)
| MOVOU X0, 144(DI)
| MOVOU X0, 160(DI)
| MOVOU X0, 176(DI)
| MOVOU X0, 192(DI)
| MOVOU X0, 208(DI)
| MOVOU X0, 224(DI)
| MOVOU X0, 240(DI)
| SUBL $256, BX
| ADDL $256, DI
| CMPL BX, $256
| JAE loop
| JMP tail
|
| _1or2:
| MOVB AX, (DI)
| MOVB AX, -1(DI)(BX*1)
| RET
| _0:
| RET
| _3:
| MOVW AX, (DI)
| MOVB AX, 2(DI)
| RET
| _4:
| // We need a separate case for 4 to make sure we clear pointers atomically.
| MOVL AX, (DI)
| RET
| _5through8:
| MOVL AX, (DI)
| MOVL AX, -4(DI)(BX*1)
| RET
| _9through16:
| MOVL AX, (DI)
| MOVL AX, 4(DI)
| MOVL AX, -8(DI)(BX*1)
| MOVL AX, -4(DI)(BX*1)
| RET
| _17through32:
| MOVOU X0, (DI)
| MOVOU X0, -16(DI)(BX*1)
| RET
| _33through64:
| MOVOU X0, (DI)
| MOVOU X0, 16(DI)
| MOVOU X0, -32(DI)(BX*1)
| MOVOU X0, -16(DI)(BX*1)
| RET
| _65through128:
| MOVOU X0, (DI)
| MOVOU X0, 16(DI)
| MOVOU X0, 32(DI)
| MOVOU X0, 48(DI)
| MOVOU X0, -64(DI)(BX*1)
| MOVOU X0, -48(DI)(BX*1)
| MOVOU X0, -32(DI)(BX*1)
| MOVOU X0, -16(DI)(BX*1)
| RET
| _129through256:
| MOVOU X0, (DI)
| MOVOU X0, 16(DI)
| MOVOU X0, 32(DI)
| MOVOU X0, 48(DI)
| MOVOU X0, 64(DI)
| MOVOU X0, 80(DI)
| MOVOU X0, 96(DI)
| MOVOU X0, 112(DI)
| MOVOU X0, -128(DI)(BX*1)
| MOVOU X0, -112(DI)(BX*1)
| MOVOU X0, -96(DI)(BX*1)
| MOVOU X0, -80(DI)(BX*1)
| MOVOU X0, -64(DI)(BX*1)
| MOVOU X0, -48(DI)(BX*1)
| MOVOU X0, -32(DI)(BX*1)
| MOVOU X0, -16(DI)(BX*1)
| RET
| nosse2:
| MOVL BX, CX
| SHRL $2, CX
| REP
| STOSL
| ANDL $3, BX
| JNE tail
| RET
|
|
