mirror of
https://github.com/golang/go
synced 2024-10-03 10:31:21 -06:00
b55791e200
I removed support for jumping between functions years ago, as part of doing the instruction layout for each function separately. Given that, it makes sense to treat labels as function-scoped. This lets each function have its own 'loop' label, for example. Makes the assembly much cleaner and removes the last reason anyone would reach for the 123(PC) form instead. Note that this is on the dev.power64 branch, but it changes all the assemblers. The change will ship in Go 1.5 (perhaps after being ported into the new assembler). Came up as part of CL 167730043. LGTM=r R=r CC=austin, dave, golang-codereviews, minux https://golang.org/cl/159670043
120 lines
2.1 KiB
ArmAsm
120 lines
2.1 KiB
ArmAsm
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build !plan9
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#include "textflag.h"
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// NOTE: Windows externalthreadhandler expects memclr to preserve DX.
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// void runtime·memclr(void*, uintptr)
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TEXT runtime·memclr(SB), NOSPLIT, $0-16
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MOVQ ptr+0(FP), DI
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MOVQ n+8(FP), BX
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XORQ AX, AX
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// MOVOU seems always faster than REP STOSQ.
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tail:
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TESTQ BX, BX
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JEQ _0
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CMPQ BX, $2
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JBE _1or2
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CMPQ BX, $4
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JBE _3or4
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CMPQ BX, $8
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JBE _5through8
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CMPQ BX, $16
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JBE _9through16
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PXOR X0, X0
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CMPQ BX, $32
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JBE _17through32
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CMPQ BX, $64
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JBE _33through64
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CMPQ BX, $128
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JBE _65through128
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CMPQ BX, $256
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JBE _129through256
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// TODO: use branch table and BSR to make this just a single dispatch
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// TODO: for really big clears, use MOVNTDQ.
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loop:
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MOVOU X0, 0(DI)
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MOVOU X0, 16(DI)
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MOVOU X0, 32(DI)
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MOVOU X0, 48(DI)
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MOVOU X0, 64(DI)
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MOVOU X0, 80(DI)
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MOVOU X0, 96(DI)
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MOVOU X0, 112(DI)
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MOVOU X0, 128(DI)
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MOVOU X0, 144(DI)
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MOVOU X0, 160(DI)
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MOVOU X0, 176(DI)
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MOVOU X0, 192(DI)
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MOVOU X0, 208(DI)
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MOVOU X0, 224(DI)
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MOVOU X0, 240(DI)
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SUBQ $256, BX
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ADDQ $256, DI
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CMPQ BX, $256
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JAE loop
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JMP tail
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_1or2:
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MOVB AX, (DI)
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MOVB AX, -1(DI)(BX*1)
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RET
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_0:
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RET
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_3or4:
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MOVW AX, (DI)
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MOVW AX, -2(DI)(BX*1)
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RET
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_5through8:
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MOVL AX, (DI)
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MOVL AX, -4(DI)(BX*1)
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RET
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_9through16:
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MOVQ AX, (DI)
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MOVQ AX, -8(DI)(BX*1)
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RET
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_17through32:
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MOVOU X0, (DI)
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MOVOU X0, -16(DI)(BX*1)
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RET
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_33through64:
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MOVOU X0, (DI)
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MOVOU X0, 16(DI)
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MOVOU X0, -32(DI)(BX*1)
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MOVOU X0, -16(DI)(BX*1)
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RET
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_65through128:
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MOVOU X0, (DI)
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MOVOU X0, 16(DI)
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MOVOU X0, 32(DI)
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MOVOU X0, 48(DI)
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MOVOU X0, -64(DI)(BX*1)
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MOVOU X0, -48(DI)(BX*1)
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MOVOU X0, -32(DI)(BX*1)
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MOVOU X0, -16(DI)(BX*1)
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RET
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_129through256:
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MOVOU X0, (DI)
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MOVOU X0, 16(DI)
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MOVOU X0, 32(DI)
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MOVOU X0, 48(DI)
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MOVOU X0, 64(DI)
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MOVOU X0, 80(DI)
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MOVOU X0, 96(DI)
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MOVOU X0, 112(DI)
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MOVOU X0, -128(DI)(BX*1)
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MOVOU X0, -112(DI)(BX*1)
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MOVOU X0, -96(DI)(BX*1)
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MOVOU X0, -80(DI)(BX*1)
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MOVOU X0, -64(DI)(BX*1)
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MOVOU X0, -48(DI)(BX*1)
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MOVOU X0, -32(DI)(BX*1)
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MOVOU X0, -16(DI)(BX*1)
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RET
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