1 // Copyright 2011 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 #include "textflag.h" 6 7 // func castagnoliSSE42(crc uint32, p []byte) uint32 8 TEXT castagnoliSSE42(SB),NOSPLIT,$0 9 MOVL crc+0(FP), AX // CRC value 10 MOVL p+4(FP), SI // data pointer 11 MOVL p_len+8(FP), CX // len(p) 12 13 NOTL AX 14 15 /* If there's less than 8 bytes to process, we do it byte-by-byte. */ 16 CMPQ CX, $8 17 JL cleanup 18 19 /* Process individual bytes until the input is 8-byte aligned. */ 20 startup: 21 MOVQ SI, BX 22 ANDQ $7, BX 23 JZ aligned 24 25 CRC32B (SI), AX 26 DECQ CX 27 INCQ SI 28 JMP startup 29 30 aligned: 31 /* The input is now 8-byte aligned and we can process 8-byte chunks. */ 32 CMPQ CX, $8 33 JL cleanup 34 35 CRC32Q (SI), AX 36 ADDQ $8, SI 37 SUBQ $8, CX 38 JMP aligned 39 40 cleanup: 41 /* We may have some bytes left over that we process one at a time. */ 42 CMPQ CX, $0 43 JE done 44 45 CRC32B (SI), AX 46 INCQ SI 47 DECQ CX 48 JMP cleanup 49 50 done: 51 NOTL AX 52 MOVL AX, ret+16(FP) 53 RET 54 55 // func haveSSE42() bool 56 TEXT haveSSE42(SB),NOSPLIT,$0 57 XORQ AX, AX 58 INCL AX 59 CPUID 60 SHRQ $20, CX 61 ANDQ $1, CX 62 MOVB CX, ret+0(FP) 63 RET 64 65
