Commit | Line | Data |
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3845591f | 1 | #include <inttypes.h> |
419484b9 | 2 | #include "crc32c.h" |
3845591f JA |
3 | |
4 | /* | |
5 | * Based on a posting to lkml by Austin Zhang <austin.zhang@intel.com> | |
6 | * | |
7 | * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal. | |
8 | * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE) | |
9 | * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at: | |
10 | * http://www.intel.com/products/processor/manuals/ | |
11 | * Intel(R) 64 and IA-32 Architectures Software Developer's Manual | |
12 | * Volume 2A: Instruction Set Reference, A-M | |
13 | */ | |
14 | ||
419484b9 AC |
15 | #ifdef ARCH_HAVE_SSE |
16 | ||
3845591f JA |
17 | #if BITS_PER_LONG == 64 |
18 | #define REX_PRE "0x48, " | |
19 | #define SCALE_F 8 | |
20 | #else | |
21 | #define REX_PRE | |
22 | #define SCALE_F 4 | |
23 | #endif | |
24 | ||
25 | uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data, | |
26 | unsigned long length) | |
27 | { | |
28 | while (length--) { | |
29 | __asm__ __volatile__( | |
30 | ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1" | |
31 | :"=S"(crc) | |
32 | :"0"(crc), "c"(*data) | |
33 | ); | |
34 | data++; | |
35 | } | |
36 | ||
37 | return crc; | |
38 | } | |
39 | ||
40 | /* | |
41 | * Steps through buffer one byte at at time, calculates reflected | |
42 | * crc using table. | |
43 | */ | |
44 | uint32_t crc32c_intel(unsigned char const *data, unsigned long length) | |
45 | { | |
46 | unsigned int iquotient = length / SCALE_F; | |
47 | unsigned int iremainder = length % SCALE_F; | |
48 | #if BITS_PER_LONG == 64 | |
49 | uint64_t *ptmp = (uint64_t *) data; | |
50 | #else | |
51 | uint32_t *ptmp = (uint32_t *) data; | |
52 | #endif | |
53 | uint32_t crc = ~0; | |
54 | ||
55 | while (iquotient--) { | |
56 | __asm__ __volatile__( | |
57 | ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;" | |
58 | :"=S"(crc) | |
59 | :"0"(crc), "c"(*ptmp) | |
60 | ); | |
61 | ptmp++; | |
62 | } | |
63 | ||
64 | if (iremainder) | |
65 | crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp, | |
66 | iremainder); | |
67 | ||
68 | return crc; | |
69 | } | |
419484b9 AC |
70 | |
71 | #endif /* ARCH_HAVE_SSE */ | |
72 |