| // Copyright 2011 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| #include "textflag.h" |
| |
| // func castagnoliSSE42(crc uint32, p []byte) uint32 |
| TEXT ·castagnoliSSE42(SB),NOSPLIT,$0 |
| MOVL crc+0(FP), AX // CRC value |
| MOVL p+4(FP), SI // data pointer |
| MOVL p_len+8(FP), CX // len(p) |
| |
| NOTL AX |
| |
| /* If there's less than 8 bytes to process, we do it byte-by-byte. */ |
| CMPQ CX, $8 |
| JL cleanup |
| |
| /* Process individual bytes until the input is 8-byte aligned. */ |
| startup: |
| MOVQ SI, BX |
| ANDQ $7, BX |
| JZ aligned |
| |
| CRC32B (SI), AX |
| DECQ CX |
| INCQ SI |
| JMP startup |
| |
| aligned: |
| /* The input is now 8-byte aligned and we can process 8-byte chunks. */ |
| CMPQ CX, $8 |
| JL cleanup |
| |
| CRC32Q (SI), AX |
| ADDQ $8, SI |
| SUBQ $8, CX |
| JMP aligned |
| |
| cleanup: |
| /* We may have some bytes left over that we process one at a time. */ |
| CMPQ CX, $0 |
| JE done |
| |
| CRC32B (SI), AX |
| INCQ SI |
| DECQ CX |
| JMP cleanup |
| |
| done: |
| NOTL AX |
| MOVL AX, ret+16(FP) |
| RET |
