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// Derived from Inferno's libkern/memmove-386.s (adapted for amd64)
// http://code.google.com/p/inferno-os/source/browse/libkern/memmove-386.s
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com). All rights reserved.
// Portions Copyright 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
// +build !plan9
#include "textflag.h"
// void runtime·memmove(void*, void*, uintptr)
TEXT runtime·memmove(SB), NOSPLIT, $0-24
MOVQ to+0(FP), DI
MOVQ from+8(FP), SI
MOVQ n+16(FP), BX
// REP instructions have a high startup cost, so we handle small sizes
// with some straightline code. The REP MOVSQ instruction is really fast
// for large sizes. The cutover is approximately 2K.
tail:
// move_129through256 or smaller work whether or not the source and the
// destination memory regions overlap because they load all data into
// registers before writing it back. move_256through2048 on the other
// hand can be used only when the memory regions don't overlap or the copy
// direction is forward.
TESTQ BX, BX
JEQ move_0
CMPQ BX, $2
JBE move_1or2
CMPQ BX, $4
JBE move_3or4
CMPQ BX, $8
JBE move_5through8
CMPQ BX, $16
JBE move_9through16
CMPQ BX, $32
JBE move_17through32
CMPQ BX, $64
JBE move_33through64
CMPQ BX, $128
JBE move_65through128
CMPQ BX, $256
JBE move_129through256
// TODO: use branch table and BSR to make this just a single dispatch
/*
* check and set for backwards
*/
CMPQ SI, DI
JLS back
/*
* forward copy loop
*/
forward:
CMPQ BX, $2048
JLS move_256through2048
MOVQ BX, CX
SHRQ $3, CX
ANDQ $7, BX
REP; MOVSQ
JMP tail
back:
/*
* check overlap
*/
MOVQ SI, CX
ADDQ BX, CX
CMPQ CX, DI
JLS forward
/*
* whole thing backwards has
* adjusted addresses
*/
ADDQ BX, DI
ADDQ BX, SI
STD
/*
* copy
*/
MOVQ BX, CX
SHRQ $3, CX
ANDQ $7, BX
SUBQ $8, DI
SUBQ $8, SI
REP; MOVSQ
CLD
ADDQ $8, DI
ADDQ $8, SI
SUBQ BX, DI
SUBQ BX, SI
JMP tail
move_1or2:
MOVB (SI), AX
MOVB -1(SI)(BX*1), CX
MOVB AX, (DI)
MOVB CX, -1(DI)(BX*1)
RET
move_0:
RET
move_3or4:
MOVW (SI), AX
MOVW -2(SI)(BX*1), CX
MOVW AX, (DI)
MOVW CX, -2(DI)(BX*1)
RET
move_5through8:
MOVL (SI), AX
MOVL -4(SI)(BX*1), CX
MOVL AX, (DI)
MOVL CX, -4(DI)(BX*1)
RET
move_9through16:
MOVQ (SI), AX
MOVQ -8(SI)(BX*1), CX
MOVQ AX, (DI)
MOVQ CX, -8(DI)(BX*1)
RET
move_17through32:
MOVOU (SI), X0
MOVOU -16(SI)(BX*1), X1
MOVOU X0, (DI)
MOVOU X1, -16(DI)(BX*1)
RET
move_33through64:
MOVOU (SI), X0
MOVOU 16(SI), X1
MOVOU -32(SI)(BX*1), X2
MOVOU -16(SI)(BX*1), X3
MOVOU X0, (DI)
MOVOU X1, 16(DI)
MOVOU X2, -32(DI)(BX*1)
MOVOU X3, -16(DI)(BX*1)
RET
move_65through128:
MOVOU (SI), X0
MOVOU 16(SI), X1
MOVOU 32(SI), X2
MOVOU 48(SI), X3
MOVOU -64(SI)(BX*1), X4
MOVOU -48(SI)(BX*1), X5
MOVOU -32(SI)(BX*1), X6
MOVOU -16(SI)(BX*1), X7
MOVOU X0, (DI)
MOVOU X1, 16(DI)
MOVOU X2, 32(DI)
MOVOU X3, 48(DI)
MOVOU X4, -64(DI)(BX*1)
MOVOU X5, -48(DI)(BX*1)
MOVOU X6, -32(DI)(BX*1)
MOVOU X7, -16(DI)(BX*1)
RET
move_129through256:
MOVOU (SI), X0
MOVOU 16(SI), X1
MOVOU 32(SI), X2
MOVOU 48(SI), X3
MOVOU 64(SI), X4
MOVOU 80(SI), X5
MOVOU 96(SI), X6
MOVOU 112(SI), X7
MOVOU -128(SI)(BX*1), X8
MOVOU -112(SI)(BX*1), X9
MOVOU -96(SI)(BX*1), X10
MOVOU -80(SI)(BX*1), X11
MOVOU -64(SI)(BX*1), X12
MOVOU -48(SI)(BX*1), X13
MOVOU -32(SI)(BX*1), X14
MOVOU -16(SI)(BX*1), X15
MOVOU X0, (DI)
MOVOU X1, 16(DI)
MOVOU X2, 32(DI)
MOVOU X3, 48(DI)
MOVOU X4, 64(DI)
MOVOU X5, 80(DI)
MOVOU X6, 96(DI)
MOVOU X7, 112(DI)
MOVOU X8, -128(DI)(BX*1)
MOVOU X9, -112(DI)(BX*1)
MOVOU X10, -96(DI)(BX*1)
MOVOU X11, -80(DI)(BX*1)
MOVOU X12, -64(DI)(BX*1)
MOVOU X13, -48(DI)(BX*1)
MOVOU X14, -32(DI)(BX*1)
MOVOU X15, -16(DI)(BX*1)
RET
move_256through2048:
SUBQ $256, BX
MOVOU (SI), X0
MOVOU 16(SI), X1
MOVOU 32(SI), X2
MOVOU 48(SI), X3
MOVOU 64(SI), X4
MOVOU 80(SI), X5
MOVOU 96(SI), X6
MOVOU 112(SI), X7
MOVOU 128(SI), X8
MOVOU 144(SI), X9
MOVOU 160(SI), X10
MOVOU 176(SI), X11
MOVOU 192(SI), X12
MOVOU 208(SI), X13
MOVOU 224(SI), X14
MOVOU 240(SI), X15
MOVOU X0, (DI)
MOVOU X1, 16(DI)
MOVOU X2, 32(DI)
MOVOU X3, 48(DI)
MOVOU X4, 64(DI)
MOVOU X5, 80(DI)
MOVOU X6, 96(DI)
MOVOU X7, 112(DI)
MOVOU X8, 128(DI)
MOVOU X9, 144(DI)
MOVOU X10, 160(DI)
MOVOU X11, 176(DI)
MOVOU X12, 192(DI)
MOVOU X13, 208(DI)
MOVOU X14, 224(DI)
MOVOU X15, 240(DI)
CMPQ BX, $256
LEAQ 256(SI), SI
LEAQ 256(DI), DI
JGE move_256through2048
JMP tail
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