| // Derived from Inferno's libkern/memmove-386.s (adapted for amd64) |
| // https://bitbucket.org/inferno-os/inferno-os/src/default/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 "go_asm.h" |
| #include "textflag.h" |
| |
| // See memmove Go doc for important implementation constraints. |
| |
| // func memmove(to, from unsafe.Pointer, n 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. |
| // |
| // BSR+branch table make almost all memmove/memclr benchmarks worse. Not worth doing. |
| TESTQ BX, BX |
| JEQ move_0 |
| CMPQ BX, $2 |
| JBE move_1or2 |
| CMPQ BX, $4 |
| JB move_3 |
| JBE move_4 |
| CMPQ BX, $8 |
| JB move_5through7 |
| JE move_8 |
| 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 |
| |
| TESTB $1, runtime·useAVXmemmove(SB) |
| JNZ avxUnaligned |
| |
| /* |
| * check and set for backwards |
| */ |
| CMPQ SI, DI |
| JLS back |
| |
| /* |
| * forward copy loop |
| */ |
| forward: |
| CMPQ BX, $2048 |
| JLS move_256through2048 |
| |
| // If REP MOVSB isn't fast, don't use it |
| CMPB internal∕cpu·X86+const_offsetX86HasERMS(SB), $1 // enhanced REP MOVSB/STOSB |
| JNE fwdBy8 |
| |
| // Check alignment |
| MOVL SI, AX |
| ORL DI, AX |
| TESTL $7, AX |
| JEQ fwdBy8 |
| |
| // Do 1 byte at a time |
| MOVQ BX, CX |
| REP; MOVSB |
| RET |
| |
| fwdBy8: |
| // Do 8 bytes at a time |
| 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_4: |
| MOVL (SI), AX |
| MOVL AX, (DI) |
| RET |
| move_3: |
| MOVW (SI), AX |
| MOVB 2(SI), CX |
| MOVW AX, (DI) |
| MOVB CX, 2(DI) |
| RET |
| move_5through7: |
| MOVL (SI), AX |
| MOVL -4(SI)(BX*1), CX |
| MOVL AX, (DI) |
| MOVL CX, -4(DI)(BX*1) |
| RET |
| move_8: |
| // We need a separate case for 8 to make sure we write pointers atomically. |
| MOVQ (SI), AX |
| MOVQ AX, (DI) |
| 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 |
| |
| avxUnaligned: |
| // There are two implementations of move algorithm. |
| // The first one for non-overlapped memory regions. It uses forward copying. |
| // The second one for overlapped regions. It uses backward copying |
| MOVQ DI, CX |
| SUBQ SI, CX |
| // Now CX contains distance between SRC and DEST |
| CMPQ CX, BX |
| // If the distance lesser than region length it means that regions are overlapped |
| JC copy_backward |
| |
| // Non-temporal copy would be better for big sizes. |
| CMPQ BX, $0x100000 |
| JAE gobble_big_data_fwd |
| |
| // Memory layout on the source side |
| // SI CX |
| // |<---------BX before correction--------->| |
| // | |<--BX corrected-->| | |
| // | | |<--- AX --->| |
| // |<-R11->| |<-128 bytes->| |
| // +----------------------------------------+ |
| // | Head | Body | Tail | |
| // +-------+------------------+-------------+ |
| // ^ ^ ^ |
| // | | | |
| // Save head into Y4 Save tail into X5..X12 |
| // | |
| // SI+R11, where R11 = ((DI & -32) + 32) - DI |
| // Algorithm: |
| // 1. Unaligned save of the tail's 128 bytes |
| // 2. Unaligned save of the head's 32 bytes |
| // 3. Destination-aligned copying of body (128 bytes per iteration) |
| // 4. Put head on the new place |
| // 5. Put the tail on the new place |
| // It can be important to satisfy processor's pipeline requirements for |
| // small sizes as the cost of unaligned memory region copying is |
| // comparable with the cost of main loop. So code is slightly messed there. |
| // There is more clean implementation of that algorithm for bigger sizes |
| // where the cost of unaligned part copying is negligible. |
| // You can see it after gobble_big_data_fwd label. |
| LEAQ (SI)(BX*1), CX |
| MOVQ DI, R10 |
| // CX points to the end of buffer so we need go back slightly. We will use negative offsets there. |
| MOVOU -0x80(CX), X5 |
| MOVOU -0x70(CX), X6 |
| MOVQ $0x80, AX |
| // Align destination address |
| ANDQ $-32, DI |
| ADDQ $32, DI |
| // Continue tail saving. |
| MOVOU -0x60(CX), X7 |
| MOVOU -0x50(CX), X8 |
| // Make R11 delta between aligned and unaligned destination addresses. |
| MOVQ DI, R11 |
| SUBQ R10, R11 |
| // Continue tail saving. |
| MOVOU -0x40(CX), X9 |
| MOVOU -0x30(CX), X10 |
| // Let's make bytes-to-copy value adjusted as we've prepared unaligned part for copying. |
| SUBQ R11, BX |
| // Continue tail saving. |
| MOVOU -0x20(CX), X11 |
| MOVOU -0x10(CX), X12 |
| // The tail will be put on its place after main body copying. |
| // It's time for the unaligned heading part. |
| VMOVDQU (SI), Y4 |
| // Adjust source address to point past head. |
| ADDQ R11, SI |
| SUBQ AX, BX |
| // Aligned memory copying there |
| gobble_128_loop: |
| VMOVDQU (SI), Y0 |
| VMOVDQU 0x20(SI), Y1 |
| VMOVDQU 0x40(SI), Y2 |
| VMOVDQU 0x60(SI), Y3 |
| ADDQ AX, SI |
| VMOVDQA Y0, (DI) |
| VMOVDQA Y1, 0x20(DI) |
| VMOVDQA Y2, 0x40(DI) |
| VMOVDQA Y3, 0x60(DI) |
| ADDQ AX, DI |
| SUBQ AX, BX |
| JA gobble_128_loop |
| // Now we can store unaligned parts. |
| ADDQ AX, BX |
| ADDQ DI, BX |
| VMOVDQU Y4, (R10) |
| VZEROUPPER |
| MOVOU X5, -0x80(BX) |
| MOVOU X6, -0x70(BX) |
| MOVOU X7, -0x60(BX) |
| MOVOU X8, -0x50(BX) |
| MOVOU X9, -0x40(BX) |
| MOVOU X10, -0x30(BX) |
| MOVOU X11, -0x20(BX) |
| MOVOU X12, -0x10(BX) |
| RET |
| |
| gobble_big_data_fwd: |
| // There is forward copying for big regions. |
| // It uses non-temporal mov instructions. |
| // Details of this algorithm are commented previously for small sizes. |
| LEAQ (SI)(BX*1), CX |
| MOVOU -0x80(SI)(BX*1), X5 |
| MOVOU -0x70(CX), X6 |
| MOVOU -0x60(CX), X7 |
| MOVOU -0x50(CX), X8 |
| MOVOU -0x40(CX), X9 |
| MOVOU -0x30(CX), X10 |
| MOVOU -0x20(CX), X11 |
| MOVOU -0x10(CX), X12 |
| VMOVDQU (SI), Y4 |
| MOVQ DI, R8 |
| ANDQ $-32, DI |
| ADDQ $32, DI |
| MOVQ DI, R10 |
| SUBQ R8, R10 |
| SUBQ R10, BX |
| ADDQ R10, SI |
| LEAQ (DI)(BX*1), CX |
| SUBQ $0x80, BX |
| gobble_mem_fwd_loop: |
| PREFETCHNTA 0x1C0(SI) |
| PREFETCHNTA 0x280(SI) |
| // Prefetch values were chosen empirically. |
| // Approach for prefetch usage as in 7.6.6 of [1] |
| // [1] 64-ia-32-architectures-optimization-manual.pdf |
| // https://www.intel.ru/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-optimization-manual.pdf |
| VMOVDQU (SI), Y0 |
| VMOVDQU 0x20(SI), Y1 |
| VMOVDQU 0x40(SI), Y2 |
| VMOVDQU 0x60(SI), Y3 |
| ADDQ $0x80, SI |
| VMOVNTDQ Y0, (DI) |
| VMOVNTDQ Y1, 0x20(DI) |
| VMOVNTDQ Y2, 0x40(DI) |
| VMOVNTDQ Y3, 0x60(DI) |
| ADDQ $0x80, DI |
| SUBQ $0x80, BX |
| JA gobble_mem_fwd_loop |
| // NT instructions don't follow the normal cache-coherency rules. |
| // We need SFENCE there to make copied data available timely. |
| SFENCE |
| VMOVDQU Y4, (R8) |
| VZEROUPPER |
| MOVOU X5, -0x80(CX) |
| MOVOU X6, -0x70(CX) |
| MOVOU X7, -0x60(CX) |
| MOVOU X8, -0x50(CX) |
| MOVOU X9, -0x40(CX) |
| MOVOU X10, -0x30(CX) |
| MOVOU X11, -0x20(CX) |
| MOVOU X12, -0x10(CX) |
| RET |
| |
| copy_backward: |
| MOVQ DI, AX |
| // Backward copying is about the same as the forward one. |
| // Firstly we load unaligned tail in the beginning of region. |
| MOVOU (SI), X5 |
| MOVOU 0x10(SI), X6 |
| ADDQ BX, DI |
| MOVOU 0x20(SI), X7 |
| MOVOU 0x30(SI), X8 |
| LEAQ -0x20(DI), R10 |
| MOVQ DI, R11 |
| MOVOU 0x40(SI), X9 |
| MOVOU 0x50(SI), X10 |
| ANDQ $0x1F, R11 |
| MOVOU 0x60(SI), X11 |
| MOVOU 0x70(SI), X12 |
| XORQ R11, DI |
| // Let's point SI to the end of region |
| ADDQ BX, SI |
| // and load unaligned head into X4. |
| VMOVDQU -0x20(SI), Y4 |
| SUBQ R11, SI |
| SUBQ R11, BX |
| // If there is enough data for non-temporal moves go to special loop |
| CMPQ BX, $0x100000 |
| JA gobble_big_data_bwd |
| SUBQ $0x80, BX |
| gobble_mem_bwd_loop: |
| VMOVDQU -0x20(SI), Y0 |
| VMOVDQU -0x40(SI), Y1 |
| VMOVDQU -0x60(SI), Y2 |
| VMOVDQU -0x80(SI), Y3 |
| SUBQ $0x80, SI |
| VMOVDQA Y0, -0x20(DI) |
| VMOVDQA Y1, -0x40(DI) |
| VMOVDQA Y2, -0x60(DI) |
| VMOVDQA Y3, -0x80(DI) |
| SUBQ $0x80, DI |
| SUBQ $0x80, BX |
| JA gobble_mem_bwd_loop |
| // Let's store unaligned data |
| VMOVDQU Y4, (R10) |
| VZEROUPPER |
| MOVOU X5, (AX) |
| MOVOU X6, 0x10(AX) |
| MOVOU X7, 0x20(AX) |
| MOVOU X8, 0x30(AX) |
| MOVOU X9, 0x40(AX) |
| MOVOU X10, 0x50(AX) |
| MOVOU X11, 0x60(AX) |
| MOVOU X12, 0x70(AX) |
| RET |
| |
| gobble_big_data_bwd: |
| SUBQ $0x80, BX |
| gobble_big_mem_bwd_loop: |
| PREFETCHNTA -0x1C0(SI) |
| PREFETCHNTA -0x280(SI) |
| VMOVDQU -0x20(SI), Y0 |
| VMOVDQU -0x40(SI), Y1 |
| VMOVDQU -0x60(SI), Y2 |
| VMOVDQU -0x80(SI), Y3 |
| SUBQ $0x80, SI |
| VMOVNTDQ Y0, -0x20(DI) |
| VMOVNTDQ Y1, -0x40(DI) |
| VMOVNTDQ Y2, -0x60(DI) |
| VMOVNTDQ Y3, -0x80(DI) |
| SUBQ $0x80, DI |
| SUBQ $0x80, BX |
| JA gobble_big_mem_bwd_loop |
| SFENCE |
| VMOVDQU Y4, (R10) |
| VZEROUPPER |
| MOVOU X5, (AX) |
| MOVOU X6, 0x10(AX) |
| MOVOU X7, 0x20(AX) |
| MOVOU X8, 0x30(AX) |
| MOVOU X9, 0x40(AX) |
| MOVOU X10, 0x50(AX) |
| MOVOU X11, 0x60(AX) |
| MOVOU X12, 0x70(AX) |
| RET |
