Commit | Line | Data |
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3845591f | 1 | #include <inttypes.h> |
5d7c5d34 JA |
2 | #include <string.h> |
3 | #include <unistd.h> | |
4 | #include <stdlib.h> | |
5 | #include <signal.h> | |
6 | #include <sys/types.h> | |
7 | #include <sys/wait.h> | |
419484b9 | 8 | #include "crc32c.h" |
3845591f JA |
9 | |
10 | /* | |
11 | * Based on a posting to lkml by Austin Zhang <austin.zhang@intel.com> | |
12 | * | |
13 | * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal. | |
14 | * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE) | |
15 | * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at: | |
16 | * http://www.intel.com/products/processor/manuals/ | |
17 | * Intel(R) 64 and IA-32 Architectures Software Developer's Manual | |
18 | * Volume 2A: Instruction Set Reference, A-M | |
19 | */ | |
20 | ||
e3aaafc4 JA |
21 | int crc32c_intel_available = 0; |
22 | ||
2f68124f | 23 | #ifdef ARCH_HAVE_SSE4_2 |
419484b9 | 24 | |
3845591f JA |
25 | #if BITS_PER_LONG == 64 |
26 | #define REX_PRE "0x48, " | |
27 | #define SCALE_F 8 | |
28 | #else | |
29 | #define REX_PRE | |
30 | #define SCALE_F 4 | |
31 | #endif | |
32 | ||
e3aaafc4 JA |
33 | static int crc32c_probed; |
34 | ||
cc62ea70 JA |
35 | static uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data, |
36 | unsigned long length) | |
3845591f JA |
37 | { |
38 | while (length--) { | |
39 | __asm__ __volatile__( | |
40 | ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1" | |
41 | :"=S"(crc) | |
42 | :"0"(crc), "c"(*data) | |
43 | ); | |
44 | data++; | |
45 | } | |
46 | ||
47 | return crc; | |
48 | } | |
49 | ||
50 | /* | |
51 | * Steps through buffer one byte at at time, calculates reflected | |
52 | * crc using table. | |
53 | */ | |
54 | uint32_t crc32c_intel(unsigned char const *data, unsigned long length) | |
55 | { | |
56 | unsigned int iquotient = length / SCALE_F; | |
57 | unsigned int iremainder = length % SCALE_F; | |
58 | #if BITS_PER_LONG == 64 | |
59 | uint64_t *ptmp = (uint64_t *) data; | |
60 | #else | |
61 | uint32_t *ptmp = (uint32_t *) data; | |
62 | #endif | |
63 | uint32_t crc = ~0; | |
64 | ||
65 | while (iquotient--) { | |
66 | __asm__ __volatile__( | |
67 | ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;" | |
68 | :"=S"(crc) | |
69 | :"0"(crc), "c"(*ptmp) | |
70 | ); | |
71 | ptmp++; | |
72 | } | |
73 | ||
74 | if (iremainder) | |
75 | crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp, | |
76 | iremainder); | |
77 | ||
78 | return crc; | |
79 | } | |
419484b9 | 80 | |
e0ab5f97 JA |
81 | static void do_cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx, |
82 | unsigned int *edx) | |
5d7c5d34 | 83 | { |
e0ab5f97 JA |
84 | int id = *eax; |
85 | ||
86 | asm("movl %4, %%eax;" | |
87 | "cpuid;" | |
88 | "movl %%eax, %0;" | |
89 | "movl %%ebx, %1;" | |
90 | "movl %%ecx, %2;" | |
91 | "movl %%edx, %3;" | |
92 | : "=r" (*eax), "=r" (*ebx), "=r" (*ecx), "=r" (*edx) | |
93 | : "r" (id) | |
94 | : "eax", "ebx", "ecx", "edx"); | |
5d7c5d34 JA |
95 | } |
96 | ||
e3aaafc4 | 97 | void crc32c_intel_probe(void) |
5d7c5d34 | 98 | { |
e3aaafc4 JA |
99 | if (!crc32c_probed) { |
100 | unsigned int eax, ebx, ecx, edx; | |
419484b9 | 101 | |
e3aaafc4 | 102 | eax = 1; |
e0ab5f97 | 103 | |
e3aaafc4 JA |
104 | do_cpuid(&eax, &ebx, &ecx, &edx); |
105 | crc32c_intel_available = (ecx & (1 << 20)) != 0; | |
106 | crc32c_probed = 1; | |
107 | } | |
5d7c5d34 JA |
108 | } |
109 | ||
110 | #endif /* ARCH_HAVE_SSE */ |