11 * Based on a posting to lkml by Austin Zhang <austin.zhang@intel.com>
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
21 bool crc32c_intel_available = false;
23 #ifdef ARCH_HAVE_SSE4_2
25 #if BITS_PER_LONG == 64
26 #define REX_PRE "0x48, "
33 static bool crc32c_probed;
35 static uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data,
40 ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
51 * Steps through buffer one byte at at time, calculates reflected
54 uint32_t crc32c_intel(unsigned char const *data, unsigned long length)
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;
61 uint32_t *ptmp = (uint32_t *) data;
67 ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
75 crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
81 void crc32c_intel_probe(void)
84 unsigned int eax, ebx, ecx = 0, edx;
88 do_cpuid(&eax, &ebx, &ecx, &edx);
89 crc32c_intel_available = (ecx & (1 << 20)) != 0;
94 #endif /* ARCH_HAVE_SSE */