summaryrefslogtreecommitdiff
path: root/src/pkg/hash/crc32/crc32_amd64p32.s
diff options
context:
space:
mode:
Diffstat (limited to 'src/pkg/hash/crc32/crc32_amd64p32.s')
-rw-r--r--src/pkg/hash/crc32/crc32_amd64p32.s64
1 files changed, 64 insertions, 0 deletions
diff --git a/src/pkg/hash/crc32/crc32_amd64p32.s b/src/pkg/hash/crc32/crc32_amd64p32.s
new file mode 100644
index 000000000..e34f20867
--- /dev/null
+++ b/src/pkg/hash/crc32/crc32_amd64p32.s
@@ -0,0 +1,64 @@
+// 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 "../../../cmd/ld/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
+
+// func haveSSE42() bool
+TEXT ·haveSSE42(SB),NOSPLIT,$0
+ XORQ AX, AX
+ INCL AX
+ CPUID
+ SHRQ $20, CX
+ ANDQ $1, CX
+ MOVB CX, ret+0(FP)
+ RET
+