| // 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. |
| |
| // See memclrNoHeapPointers Go doc for important implementation constraints. |
| |
| // 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 |
