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589 lines
24 KiB
589 lines
24 KiB
/* crc32 for POWER8 using VSX instructions |
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* Copyright (C) 2021 IBM Corporation |
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* |
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* Author: Rogerio Alves <rogealve@br.ibm.com> |
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* |
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* For conditions of distribution and use, see copyright notice in zlib.h |
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* |
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* Calculate the checksum of data that is 16 byte aligned and a multiple of |
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* 16 bytes. |
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* |
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* The first step is to reduce it to 1024 bits. We do this in 8 parallel |
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* chunks in order to mask the latency of the vpmsum instructions. If we |
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* have more than 32 kB of data to checksum we repeat this step multiple |
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* times, passing in the previous 1024 bits. |
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* |
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* The next step is to reduce the 1024 bits to 64 bits. This step adds |
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* 32 bits of 0s to the end - this matches what a CRC does. We just |
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* calculate constants that land the data in this 32 bits. |
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* |
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* We then use fixed point Barrett reduction to compute a mod n over GF(2) |
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* for n = CRC using POWER8 instructions. We use x = 32. |
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* |
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* http://en.wikipedia.org/wiki/Barrett_reduction |
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* |
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* This code uses gcc vector builtins instead using assembly directly. |
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*/ |
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#include <altivec.h> |
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#include "zendian.h" |
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#include "zbuild.h" |
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#include "crc32_constants.h" |
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#include "crc32_braid_tbl.h" |
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#if defined (__clang__) |
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#include "fallback_builtins.h" |
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#endif |
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#define MAX_SIZE 32768 |
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#define VMX_ALIGN 16 |
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#define VMX_ALIGN_MASK (VMX_ALIGN-1) |
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static unsigned int crc32_align(unsigned int crc, const unsigned char *p, unsigned long len) { |
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while (len--) |
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crc = crc_table[(crc ^ *p++) & 0xff] ^ (crc >> 8); |
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return crc; |
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} |
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static unsigned int ALIGNED_(32) __crc32_vpmsum(unsigned int crc, const void* p, unsigned long len); |
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Z_INTERNAL uint32_t crc32_power8(uint32_t crc, const unsigned char *p, size_t _len) { |
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unsigned int prealign; |
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unsigned int tail; |
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unsigned long len = (unsigned long) _len; |
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if (p == (const unsigned char *) 0x0) |
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return 0; |
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crc ^= 0xffffffff; |
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if (len < VMX_ALIGN + VMX_ALIGN_MASK) { |
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crc = crc32_align(crc, p, len); |
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goto out; |
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} |
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if ((unsigned long)p & VMX_ALIGN_MASK) { |
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prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK); |
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crc = crc32_align(crc, p, prealign); |
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len -= prealign; |
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p += prealign; |
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} |
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crc = __crc32_vpmsum(crc, p, len & ~VMX_ALIGN_MASK); |
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tail = len & VMX_ALIGN_MASK; |
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if (tail) { |
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p += len & ~VMX_ALIGN_MASK; |
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crc = crc32_align(crc, p, tail); |
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} |
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out: |
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crc ^= 0xffffffff; |
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return crc; |
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} |
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/* When we have a load-store in a single-dispatch group and address overlap |
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* such that forward is not allowed (load-hit-store) the group must be flushed. |
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* A group ending NOP prevents the flush. |
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*/ |
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#define GROUP_ENDING_NOP __asm__("ori 2,2,0" ::: "memory") |
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#if BYTE_ORDER == BIG_ENDIAN |
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#define BYTESWAP_DATA |
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#endif |
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#ifdef BYTESWAP_DATA |
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#define VEC_PERM(vr, va, vb, vc) vr = vec_perm(va, vb, (__vector unsigned char) vc) |
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#if BYTE_ORDER == LITTLE_ENDIAN |
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/* Byte reverse permute constant LE. */ |
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static const __vector unsigned long long vperm_const ALIGNED_(16) = { 0x08090A0B0C0D0E0FUL, 0x0001020304050607UL }; |
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#else |
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static const __vector unsigned long long vperm_const ALIGNED_(16) = { 0x0F0E0D0C0B0A0908UL, 0X0706050403020100UL }; |
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#endif |
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#else |
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#define VEC_PERM(vr, va, vb, vc) |
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#endif |
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static unsigned int ALIGNED_(32) __crc32_vpmsum(unsigned int crc, const void* p, unsigned long len) { |
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const __vector unsigned long long vzero = {0,0}; |
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const __vector unsigned long long vones = {0xffffffffffffffffUL, 0xffffffffffffffffUL}; |
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const __vector unsigned long long vmask_32bit = |
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(__vector unsigned long long)vec_sld((__vector unsigned char)vzero, (__vector unsigned char)vones, 4); |
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const __vector unsigned long long vmask_64bit = |
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(__vector unsigned long long)vec_sld((__vector unsigned char)vzero, (__vector unsigned char)vones, 8); |
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__vector unsigned long long vcrc; |
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__vector unsigned long long vconst1, vconst2; |
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/* vdata0-vdata7 will contain our data (p). */ |
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__vector unsigned long long vdata0, vdata1, vdata2, vdata3, vdata4, vdata5, vdata6, vdata7; |
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/* v0-v7 will contain our checksums */ |
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__vector unsigned long long v0 = {0,0}; |
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__vector unsigned long long v1 = {0,0}; |
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__vector unsigned long long v2 = {0,0}; |
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__vector unsigned long long v3 = {0,0}; |
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__vector unsigned long long v4 = {0,0}; |
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__vector unsigned long long v5 = {0,0}; |
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__vector unsigned long long v6 = {0,0}; |
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__vector unsigned long long v7 = {0,0}; |
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/* Vector auxiliary variables. */ |
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__vector unsigned long long va0, va1, va2, va3, va4, va5, va6, va7; |
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unsigned int offset; /* Constant table offset. */ |
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unsigned long i; /* Counter. */ |
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unsigned long chunks; |
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unsigned long block_size; |
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int next_block = 0; |
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/* Align by 128 bits. The last 128 bit block will be processed at end. */ |
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unsigned long length = len & 0xFFFFFFFFFFFFFF80UL; |
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vcrc = (__vector unsigned long long)__builtin_pack_vector_int128(0UL, crc); |
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/* Short version. */ |
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if (len < 256) { |
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/* Calculate where in the constant table we need to start. */ |
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offset = 256 - len; |
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vconst1 = vec_ld(offset, vcrc_short_const); |
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vdata0 = vec_ld(0, (__vector unsigned long long*) p); |
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VEC_PERM(vdata0, vdata0, vconst1, vperm_const); |
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/* xor initial value */ |
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vdata0 = vec_xor(vdata0, vcrc); |
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vdata0 = (__vector unsigned long long) __builtin_crypto_vpmsumw( |
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(__vector unsigned int)vdata0, (__vector unsigned int)vconst1); |
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v0 = vec_xor(v0, vdata0); |
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for (i = 16; i < len; i += 16) { |
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vconst1 = vec_ld(offset + i, vcrc_short_const); |
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vdata0 = vec_ld(i, (__vector unsigned long long*) p); |
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VEC_PERM(vdata0, vdata0, vconst1, vperm_const); |
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vdata0 = (__vector unsigned long long) __builtin_crypto_vpmsumw( |
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(__vector unsigned int)vdata0, (__vector unsigned int)vconst1); |
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v0 = vec_xor(v0, vdata0); |
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} |
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} else { |
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/* Load initial values. */ |
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vdata0 = vec_ld(0, (__vector unsigned long long*) p); |
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vdata1 = vec_ld(16, (__vector unsigned long long*) p); |
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VEC_PERM(vdata0, vdata0, vdata0, vperm_const); |
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VEC_PERM(vdata1, vdata1, vdata1, vperm_const); |
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vdata2 = vec_ld(32, (__vector unsigned long long*) p); |
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vdata3 = vec_ld(48, (__vector unsigned long long*) p); |
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VEC_PERM(vdata2, vdata2, vdata2, vperm_const); |
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VEC_PERM(vdata3, vdata3, vdata3, vperm_const); |
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vdata4 = vec_ld(64, (__vector unsigned long long*) p); |
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vdata5 = vec_ld(80, (__vector unsigned long long*) p); |
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VEC_PERM(vdata4, vdata4, vdata4, vperm_const); |
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VEC_PERM(vdata5, vdata5, vdata5, vperm_const); |
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vdata6 = vec_ld(96, (__vector unsigned long long*) p); |
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vdata7 = vec_ld(112, (__vector unsigned long long*) p); |
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VEC_PERM(vdata6, vdata6, vdata6, vperm_const); |
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VEC_PERM(vdata7, vdata7, vdata7, vperm_const); |
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/* xor in initial value */ |
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vdata0 = vec_xor(vdata0, vcrc); |
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p = (char *)p + 128; |
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do { |
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/* Checksum in blocks of MAX_SIZE. */ |
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block_size = length; |
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if (block_size > MAX_SIZE) { |
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block_size = MAX_SIZE; |
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} |
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length = length - block_size; |
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/* |
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* Work out the offset into the constants table to start at. Each |
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* constant is 16 bytes, and it is used against 128 bytes of input |
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* data - 128 / 16 = 8 |
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*/ |
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offset = (MAX_SIZE/8) - (block_size/8); |
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/* We reduce our final 128 bytes in a separate step */ |
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chunks = (block_size/128)-1; |
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vconst1 = vec_ld(offset, vcrc_const); |
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va0 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata0, |
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(__vector unsigned long long)vconst1); |
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va1 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata1, |
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(__vector unsigned long long)vconst1); |
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va2 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata2, |
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(__vector unsigned long long)vconst1); |
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va3 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata3, |
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(__vector unsigned long long)vconst1); |
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va4 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata4, |
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(__vector unsigned long long)vconst1); |
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va5 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata5, |
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(__vector unsigned long long)vconst1); |
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va6 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata6, |
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(__vector unsigned long long)vconst1); |
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va7 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata7, |
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(__vector unsigned long long)vconst1); |
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if (chunks > 1) { |
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offset += 16; |
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vconst2 = vec_ld(offset, vcrc_const); |
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GROUP_ENDING_NOP; |
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vdata0 = vec_ld(0, (__vector unsigned long long*) p); |
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VEC_PERM(vdata0, vdata0, vdata0, vperm_const); |
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vdata1 = vec_ld(16, (__vector unsigned long long*) p); |
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VEC_PERM(vdata1, vdata1, vdata1, vperm_const); |
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vdata2 = vec_ld(32, (__vector unsigned long long*) p); |
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VEC_PERM(vdata2, vdata2, vdata2, vperm_const); |
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vdata3 = vec_ld(48, (__vector unsigned long long*) p); |
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VEC_PERM(vdata3, vdata3, vdata3, vperm_const); |
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vdata4 = vec_ld(64, (__vector unsigned long long*) p); |
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VEC_PERM(vdata4, vdata4, vdata4, vperm_const); |
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vdata5 = vec_ld(80, (__vector unsigned long long*) p); |
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VEC_PERM(vdata5, vdata5, vdata5, vperm_const); |
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vdata6 = vec_ld(96, (__vector unsigned long long*) p); |
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VEC_PERM(vdata6, vdata6, vdata6, vperm_const); |
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vdata7 = vec_ld(112, (__vector unsigned long long*) p); |
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VEC_PERM(vdata7, vdata7, vdata7, vperm_const); |
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p = (char *)p + 128; |
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/* |
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* main loop. Each iteration calculates the CRC for a 128-byte |
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* block. |
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*/ |
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for (i = 0; i < chunks-2; i++) { |
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vconst1 = vec_ld(offset, vcrc_const); |
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offset += 16; |
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GROUP_ENDING_NOP; |
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v0 = vec_xor(v0, va0); |
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va0 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata0, |
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(__vector unsigned long long)vconst2); |
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vdata0 = vec_ld(0, (__vector unsigned long long*) p); |
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VEC_PERM(vdata0, vdata0, vdata0, vperm_const); |
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GROUP_ENDING_NOP; |
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v1 = vec_xor(v1, va1); |
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va1 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata1, |
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(__vector unsigned long long)vconst2); |
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vdata1 = vec_ld(16, (__vector unsigned long long*) p); |
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VEC_PERM(vdata1, vdata1, vdata1, vperm_const); |
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GROUP_ENDING_NOP; |
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v2 = vec_xor(v2, va2); |
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va2 = __builtin_crypto_vpmsumd((__vector unsigned long long) |
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vdata2, (__vector unsigned long long)vconst2); |
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vdata2 = vec_ld(32, (__vector unsigned long long*) p); |
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VEC_PERM(vdata2, vdata2, vdata2, vperm_const); |
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GROUP_ENDING_NOP; |
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v3 = vec_xor(v3, va3); |
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va3 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata3, |
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(__vector unsigned long long)vconst2); |
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vdata3 = vec_ld(48, (__vector unsigned long long*) p); |
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VEC_PERM(vdata3, vdata3, vdata3, vperm_const); |
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vconst2 = vec_ld(offset, vcrc_const); |
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GROUP_ENDING_NOP; |
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v4 = vec_xor(v4, va4); |
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va4 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata4, |
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(__vector unsigned long long)vconst1); |
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vdata4 = vec_ld(64, (__vector unsigned long long*) p); |
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VEC_PERM(vdata4, vdata4, vdata4, vperm_const); |
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GROUP_ENDING_NOP; |
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v5 = vec_xor(v5, va5); |
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va5 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata5, |
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(__vector unsigned long long)vconst1); |
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vdata5 = vec_ld(80, (__vector unsigned long long*) p); |
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VEC_PERM(vdata5, vdata5, vdata5, vperm_const); |
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GROUP_ENDING_NOP; |
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v6 = vec_xor(v6, va6); |
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va6 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata6, |
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(__vector unsigned long long)vconst1); |
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vdata6 = vec_ld(96, (__vector unsigned long long*) p); |
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VEC_PERM(vdata6, vdata6, vdata6, vperm_const); |
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GROUP_ENDING_NOP; |
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v7 = vec_xor(v7, va7); |
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va7 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata7, |
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(__vector unsigned long long)vconst1); |
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vdata7 = vec_ld(112, (__vector unsigned long long*) p); |
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VEC_PERM(vdata7, vdata7, vdata7, vperm_const); |
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p = (char *)p + 128; |
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} |
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/* First cool down */ |
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vconst1 = vec_ld(offset, vcrc_const); |
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offset += 16; |
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v0 = vec_xor(v0, va0); |
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va0 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata0, |
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(__vector unsigned long long)vconst1); |
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GROUP_ENDING_NOP; |
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v1 = vec_xor(v1, va1); |
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va1 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata1, |
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(__vector unsigned long long)vconst1); |
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GROUP_ENDING_NOP; |
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v2 = vec_xor(v2, va2); |
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va2 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata2, |
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(__vector unsigned long long)vconst1); |
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GROUP_ENDING_NOP; |
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v3 = vec_xor(v3, va3); |
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va3 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata3, |
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(__vector unsigned long long)vconst1); |
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GROUP_ENDING_NOP; |
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v4 = vec_xor(v4, va4); |
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va4 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata4, |
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(__vector unsigned long long)vconst1); |
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GROUP_ENDING_NOP; |
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v5 = vec_xor(v5, va5); |
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va5 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata5, |
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(__vector unsigned long long)vconst1); |
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GROUP_ENDING_NOP; |
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v6 = vec_xor(v6, va6); |
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va6 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata6, |
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(__vector unsigned long long)vconst1); |
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GROUP_ENDING_NOP; |
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v7 = vec_xor(v7, va7); |
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va7 = __builtin_crypto_vpmsumd((__vector unsigned long long)vdata7, |
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(__vector unsigned long long)vconst1); |
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}/* else */ |
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/* Second cool down. */ |
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v0 = vec_xor(v0, va0); |
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v1 = vec_xor(v1, va1); |
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v2 = vec_xor(v2, va2); |
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v3 = vec_xor(v3, va3); |
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v4 = vec_xor(v4, va4); |
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v5 = vec_xor(v5, va5); |
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v6 = vec_xor(v6, va6); |
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v7 = vec_xor(v7, va7); |
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/* |
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* vpmsumd produces a 96 bit result in the least significant bits |
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* of the register. Since we are bit reflected we have to shift it |
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* left 32 bits so it occupies the least significant bits in the |
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* bit reflected domain. |
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*/ |
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v0 = (__vector unsigned long long)vec_sld((__vector unsigned char)v0, |
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(__vector unsigned char)vzero, 4); |
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v1 = (__vector unsigned long long)vec_sld((__vector unsigned char)v1, |
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(__vector unsigned char)vzero, 4); |
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v2 = (__vector unsigned long long)vec_sld((__vector unsigned char)v2, |
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(__vector unsigned char)vzero, 4); |
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v3 = (__vector unsigned long long)vec_sld((__vector unsigned char)v3, |
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(__vector unsigned char)vzero, 4); |
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v4 = (__vector unsigned long long)vec_sld((__vector unsigned char)v4, |
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(__vector unsigned char)vzero, 4); |
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v5 = (__vector unsigned long long)vec_sld((__vector unsigned char)v5, |
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(__vector unsigned char)vzero, 4); |
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v6 = (__vector unsigned long long)vec_sld((__vector unsigned char)v6, |
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(__vector unsigned char)vzero, 4); |
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v7 = (__vector unsigned long long)vec_sld((__vector unsigned char)v7, |
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(__vector unsigned char)vzero, 4); |
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/* xor with the last 1024 bits. */ |
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va0 = vec_ld(0, (__vector unsigned long long*) p); |
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VEC_PERM(va0, va0, va0, vperm_const); |
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va1 = vec_ld(16, (__vector unsigned long long*) p); |
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VEC_PERM(va1, va1, va1, vperm_const); |
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va2 = vec_ld(32, (__vector unsigned long long*) p); |
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VEC_PERM(va2, va2, va2, vperm_const); |
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va3 = vec_ld(48, (__vector unsigned long long*) p); |
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VEC_PERM(va3, va3, va3, vperm_const); |
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va4 = vec_ld(64, (__vector unsigned long long*) p); |
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VEC_PERM(va4, va4, va4, vperm_const); |
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va5 = vec_ld(80, (__vector unsigned long long*) p); |
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VEC_PERM(va5, va5, va5, vperm_const); |
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va6 = vec_ld(96, (__vector unsigned long long*) p); |
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VEC_PERM(va6, va6, va6, vperm_const); |
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va7 = vec_ld(112, (__vector unsigned long long*) p); |
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VEC_PERM(va7, va7, va7, vperm_const); |
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p = (char *)p + 128; |
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vdata0 = vec_xor(v0, va0); |
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vdata1 = vec_xor(v1, va1); |
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vdata2 = vec_xor(v2, va2); |
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vdata3 = vec_xor(v3, va3); |
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vdata4 = vec_xor(v4, va4); |
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vdata5 = vec_xor(v5, va5); |
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vdata6 = vec_xor(v6, va6); |
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vdata7 = vec_xor(v7, va7); |
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/* Check if we have more blocks to process */ |
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next_block = 0; |
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if (length != 0) { |
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next_block = 1; |
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/* zero v0-v7 */ |
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v0 = vec_xor(v0, v0); |
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v1 = vec_xor(v1, v1); |
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v2 = vec_xor(v2, v2); |
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v3 = vec_xor(v3, v3); |
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v4 = vec_xor(v4, v4); |
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v5 = vec_xor(v5, v5); |
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v6 = vec_xor(v6, v6); |
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v7 = vec_xor(v7, v7); |
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} |
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length = length + 128; |
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|
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} while (next_block); |
|
|
|
/* Calculate how many bytes we have left. */ |
|
length = (len & 127); |
|
|
|
/* Calculate where in (short) constant table we need to start. */ |
|
offset = 128 - length; |
|
|
|
v0 = vec_ld(offset, vcrc_short_const); |
|
v1 = vec_ld(offset + 16, vcrc_short_const); |
|
v2 = vec_ld(offset + 32, vcrc_short_const); |
|
v3 = vec_ld(offset + 48, vcrc_short_const); |
|
v4 = vec_ld(offset + 64, vcrc_short_const); |
|
v5 = vec_ld(offset + 80, vcrc_short_const); |
|
v6 = vec_ld(offset + 96, vcrc_short_const); |
|
v7 = vec_ld(offset + 112, vcrc_short_const); |
|
|
|
offset += 128; |
|
|
|
v0 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata0, (__vector unsigned int)v0); |
|
v1 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata1, (__vector unsigned int)v1); |
|
v2 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata2, (__vector unsigned int)v2); |
|
v3 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata3, (__vector unsigned int)v3); |
|
v4 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata4, (__vector unsigned int)v4); |
|
v5 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata5, (__vector unsigned int)v5); |
|
v6 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata6, (__vector unsigned int)v6); |
|
v7 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata7, (__vector unsigned int)v7); |
|
|
|
/* Now reduce the tail (0-112 bytes). */ |
|
for (i = 0; i < length; i+=16) { |
|
vdata0 = vec_ld(i,(__vector unsigned long long*)p); |
|
VEC_PERM(vdata0, vdata0, vdata0, vperm_const); |
|
va0 = vec_ld(offset + i,vcrc_short_const); |
|
va0 = (__vector unsigned long long)__builtin_crypto_vpmsumw( |
|
(__vector unsigned int)vdata0, (__vector unsigned int)va0); |
|
v0 = vec_xor(v0, va0); |
|
} |
|
|
|
/* xor all parallel chunks together. */ |
|
v0 = vec_xor(v0, v1); |
|
v2 = vec_xor(v2, v3); |
|
v4 = vec_xor(v4, v5); |
|
v6 = vec_xor(v6, v7); |
|
|
|
v0 = vec_xor(v0, v2); |
|
v4 = vec_xor(v4, v6); |
|
|
|
v0 = vec_xor(v0, v4); |
|
} |
|
|
|
/* Barrett Reduction */ |
|
vconst1 = vec_ld(0, v_Barrett_const); |
|
vconst2 = vec_ld(16, v_Barrett_const); |
|
|
|
v1 = (__vector unsigned long long)vec_sld((__vector unsigned char)v0, |
|
(__vector unsigned char)v0, 8); |
|
v0 = vec_xor(v1,v0); |
|
|
|
/* shift left one bit */ |
|
__vector unsigned char vsht_splat = vec_splat_u8 (1); |
|
v0 = (__vector unsigned long long)vec_sll((__vector unsigned char)v0, vsht_splat); |
|
|
|
v0 = vec_and(v0, vmask_64bit); |
|
|
|
/* |
|
* The reflected version of Barrett reduction. Instead of bit |
|
* reflecting our data (which is expensive to do), we bit reflect our |
|
* constants and our algorithm, which means the intermediate data in |
|
* our vector registers goes from 0-63 instead of 63-0. We can reflect |
|
* the algorithm because we don't carry in mod 2 arithmetic. |
|
*/ |
|
|
|
/* bottom 32 bits of a */ |
|
v1 = vec_and(v0, vmask_32bit); |
|
|
|
/* ma */ |
|
v1 = __builtin_crypto_vpmsumd((__vector unsigned long long)v1, |
|
(__vector unsigned long long)vconst1); |
|
|
|
/* bottom 32bits of ma */ |
|
v1 = vec_and(v1, vmask_32bit); |
|
/* qn */ |
|
v1 = __builtin_crypto_vpmsumd((__vector unsigned long long)v1, |
|
(__vector unsigned long long)vconst2); |
|
/* a - qn, subtraction is xor in GF(2) */ |
|
v0 = vec_xor (v0, v1); |
|
|
|
/* |
|
* Since we are bit reflected, the result (ie the low 32 bits) is in |
|
* the high 32 bits. We just need to shift it left 4 bytes |
|
* V0 [ 0 1 X 3 ] |
|
* V0 [ 0 X 2 3 ] |
|
*/ |
|
|
|
/* shift result into top 64 bits of */ |
|
v0 = (__vector unsigned long long)vec_sld((__vector unsigned char)v0, |
|
(__vector unsigned char)vzero, 4); |
|
|
|
#if BYTE_ORDER == BIG_ENDIAN |
|
return v0[0]; |
|
#else |
|
return v0[1]; |
|
#endif |
|
}
|
|
|