| // 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 "../../cmd/ld/textflag.h" |
| |
| // void runtime·memmove(void*, void*, uintptr) |
| TEXT runtime·memmove(SB), NOSPLIT, $0-24 |
| |
| MOVQ to+0(FP), DI |
| MOVQ fr+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 1K. We implement up to |
| // 256 because that is the maximum SSE register load (loading all data |
| // into registers lets us ignore copy direction). |
| tail: |
| 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: |
| 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) |
| 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 |
