| // 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 "textflag.h" |
| |
| // NOTE: Windows externalthreadhandler expects memclr to preserve DX. |
| |
| // void runtime·memclr(void*, uintptr) |
| TEXT runtime·memclr(SB), NOSPLIT, $0-16 |
| MOVQ ptr+0(FP), DI |
| MOVQ n+8(FP), BX |
| XORQ AX, AX |
| |
| // MOVOU seems always faster than REP STOSQ. |
| clr_tail: |
| TESTQ BX, BX |
| JEQ clr_0 |
| CMPQ BX, $2 |
| JBE clr_1or2 |
| CMPQ BX, $4 |
| JBE clr_3or4 |
| CMPQ BX, $8 |
| JBE clr_5through8 |
| CMPQ BX, $16 |
| JBE clr_9through16 |
| PXOR X0, X0 |
| CMPQ BX, $32 |
| JBE clr_17through32 |
| CMPQ BX, $64 |
| JBE clr_33through64 |
| CMPQ BX, $128 |
| JBE clr_65through128 |
| CMPQ BX, $256 |
| JBE clr_129through256 |
| // TODO: use branch table and BSR to make this just a single dispatch |
| // TODO: for really big clears, use MOVNTDQ. |
| |
| clr_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) |
| SUBQ $256, BX |
| ADDQ $256, DI |
| CMPQ BX, $256 |
| JAE clr_loop |
| JMP clr_tail |
| |
| clr_1or2: |
| MOVB AX, (DI) |
| MOVB AX, -1(DI)(BX*1) |
| RET |
| clr_0: |
| RET |
| clr_3or4: |
| MOVW AX, (DI) |
| MOVW AX, -2(DI)(BX*1) |
| RET |
| clr_5through8: |
| MOVL AX, (DI) |
| MOVL AX, -4(DI)(BX*1) |
| RET |
| clr_9through16: |
| MOVQ AX, (DI) |
| MOVQ AX, -8(DI)(BX*1) |
| RET |
| clr_17through32: |
| MOVOU X0, (DI) |
| MOVOU X0, -16(DI)(BX*1) |
| RET |
| clr_33through64: |
| MOVOU X0, (DI) |
| MOVOU X0, 16(DI) |
| MOVOU X0, -32(DI)(BX*1) |
| MOVOU X0, -16(DI)(BX*1) |
| RET |
| clr_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 |
| clr_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 |
