github.com/razvanm/vanadium-go-1.3@v0.0.0-20160721203343-4a65068e5915/src/runtime/memclr_386.s (about) 1 // Copyright 2014 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // +build !plan9 6 7 #include "textflag.h" 8 9 // NOTE: Windows externalthreadhandler expects memclr to preserve DX. 10 11 // void runtime·memclr(void*, uintptr) 12 TEXT runtime·memclr(SB), NOSPLIT, $0-8 13 MOVL ptr+0(FP), DI 14 MOVL n+4(FP), BX 15 XORL AX, AX 16 17 // MOVOU seems always faster than REP STOSL. 18 clr_tail: 19 TESTL BX, BX 20 JEQ clr_0 21 CMPL BX, $2 22 JBE clr_1or2 23 CMPL BX, $4 24 JBE clr_3or4 25 CMPL BX, $8 26 JBE clr_5through8 27 CMPL BX, $16 28 JBE clr_9through16 29 TESTL $0x4000000, runtime·cpuid_edx(SB) // check for sse2 30 JEQ nosse2 31 PXOR X0, X0 32 CMPL BX, $32 33 JBE clr_17through32 34 CMPL BX, $64 35 JBE clr_33through64 36 CMPL BX, $128 37 JBE clr_65through128 38 CMPL BX, $256 39 JBE clr_129through256 40 // TODO: use branch table and BSR to make this just a single dispatch 41 42 clr_loop: 43 MOVOU X0, 0(DI) 44 MOVOU X0, 16(DI) 45 MOVOU X0, 32(DI) 46 MOVOU X0, 48(DI) 47 MOVOU X0, 64(DI) 48 MOVOU X0, 80(DI) 49 MOVOU X0, 96(DI) 50 MOVOU X0, 112(DI) 51 MOVOU X0, 128(DI) 52 MOVOU X0, 144(DI) 53 MOVOU X0, 160(DI) 54 MOVOU X0, 176(DI) 55 MOVOU X0, 192(DI) 56 MOVOU X0, 208(DI) 57 MOVOU X0, 224(DI) 58 MOVOU X0, 240(DI) 59 SUBL $256, BX 60 ADDL $256, DI 61 CMPL BX, $256 62 JAE clr_loop 63 JMP clr_tail 64 65 clr_1or2: 66 MOVB AX, (DI) 67 MOVB AX, -1(DI)(BX*1) 68 RET 69 clr_0: 70 RET 71 clr_3or4: 72 MOVW AX, (DI) 73 MOVW AX, -2(DI)(BX*1) 74 RET 75 clr_5through8: 76 MOVL AX, (DI) 77 MOVL AX, -4(DI)(BX*1) 78 RET 79 clr_9through16: 80 MOVL AX, (DI) 81 MOVL AX, 4(DI) 82 MOVL AX, -8(DI)(BX*1) 83 MOVL AX, -4(DI)(BX*1) 84 RET 85 clr_17through32: 86 MOVOU X0, (DI) 87 MOVOU X0, -16(DI)(BX*1) 88 RET 89 clr_33through64: 90 MOVOU X0, (DI) 91 MOVOU X0, 16(DI) 92 MOVOU X0, -32(DI)(BX*1) 93 MOVOU X0, -16(DI)(BX*1) 94 RET 95 clr_65through128: 96 MOVOU X0, (DI) 97 MOVOU X0, 16(DI) 98 MOVOU X0, 32(DI) 99 MOVOU X0, 48(DI) 100 MOVOU X0, -64(DI)(BX*1) 101 MOVOU X0, -48(DI)(BX*1) 102 MOVOU X0, -32(DI)(BX*1) 103 MOVOU X0, -16(DI)(BX*1) 104 RET 105 clr_129through256: 106 MOVOU X0, (DI) 107 MOVOU X0, 16(DI) 108 MOVOU X0, 32(DI) 109 MOVOU X0, 48(DI) 110 MOVOU X0, 64(DI) 111 MOVOU X0, 80(DI) 112 MOVOU X0, 96(DI) 113 MOVOU X0, 112(DI) 114 MOVOU X0, -128(DI)(BX*1) 115 MOVOU X0, -112(DI)(BX*1) 116 MOVOU X0, -96(DI)(BX*1) 117 MOVOU X0, -80(DI)(BX*1) 118 MOVOU X0, -64(DI)(BX*1) 119 MOVOU X0, -48(DI)(BX*1) 120 MOVOU X0, -32(DI)(BX*1) 121 MOVOU X0, -16(DI)(BX*1) 122 RET 123 nosse2: 124 MOVL BX, CX 125 SHRL $2, CX 126 REP 127 STOSL 128 ANDL $3, BX 129 JNE clr_tail 130 RET