Botan  1.11.15
src/lib/modes/aead/gcm/clmul/clmul.cpp
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00001 /*
00002 * CLMUL hook
00003 * (C) 2013 Jack Lloyd
00004 *
00005 * Botan is released under the Simplified BSD License (see license.txt)
00006 */
00007 
00008 #include <botan/internal/clmul.h>
00009 #include <immintrin.h>
00010 #include <wmmintrin.h>
00011 
00012 namespace Botan {
00013 
00014 void gcm_multiply_clmul(byte x[16], const byte H[16])
00015    {
00016    /*
00017    * Algorithms 1 and 5 from Intel's CLMUL guide
00018    */
00019    const __m128i BSWAP_MASK = _mm_set_epi8(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
00020 
00021    __m128i a = _mm_loadu_si128(reinterpret_cast<const __m128i*>(&x[0]));
00022    __m128i b = _mm_loadu_si128(reinterpret_cast<const __m128i*>(&H[0]));
00023 
00024    a = _mm_shuffle_epi8(a, BSWAP_MASK);
00025    b = _mm_shuffle_epi8(b, BSWAP_MASK);
00026 
00027    __m128i T0, T1, T2, T3, T4, T5;
00028 
00029    T0 = _mm_clmulepi64_si128(a, b, 0x00);
00030    T1 = _mm_clmulepi64_si128(a, b, 0x01);
00031    T2 = _mm_clmulepi64_si128(a, b, 0x10);
00032    T3 = _mm_clmulepi64_si128(a, b, 0x11);
00033 
00034    T1 = _mm_xor_si128(T1, T2);
00035    T2 = _mm_slli_si128(T1, 8);
00036    T1 = _mm_srli_si128(T1, 8);
00037    T0 = _mm_xor_si128(T0, T2);
00038    T3 = _mm_xor_si128(T3, T1);
00039 
00040    T4 = _mm_srli_epi32(T0, 31);
00041    T0 = _mm_slli_epi32(T0, 1);
00042 
00043    T5 = _mm_srli_epi32(T3, 31);
00044    T3 = _mm_slli_epi32(T3, 1);
00045 
00046    T2 = _mm_srli_si128(T4, 12);
00047    T5 = _mm_slli_si128(T5, 4);
00048    T4 = _mm_slli_si128(T4, 4);
00049    T0 = _mm_or_si128(T0, T4);
00050    T3 = _mm_or_si128(T3, T5);
00051    T3 = _mm_or_si128(T3, T2);
00052 
00053    T4 = _mm_slli_epi32(T0, 31);
00054    T5 = _mm_slli_epi32(T0, 30);
00055    T2 = _mm_slli_epi32(T0, 25);
00056 
00057    T4 = _mm_xor_si128(T4, T5);
00058    T4 = _mm_xor_si128(T4, T2);
00059    T5 = _mm_srli_si128(T4, 4);
00060    T3 = _mm_xor_si128(T3, T5);
00061    T4 = _mm_slli_si128(T4, 12);
00062    T0 = _mm_xor_si128(T0, T4);
00063    T3 = _mm_xor_si128(T3, T0);
00064 
00065    T4 = _mm_srli_epi32(T0, 1);
00066    T1 = _mm_srli_epi32(T0, 2);
00067    T2 = _mm_srli_epi32(T0, 7);
00068    T3 = _mm_xor_si128(T3, T1);
00069    T3 = _mm_xor_si128(T3, T2);
00070    T3 = _mm_xor_si128(T3, T4);
00071 
00072    T3 = _mm_shuffle_epi8(T3, BSWAP_MASK);
00073 
00074    _mm_storeu_si128(reinterpret_cast<__m128i*>(&x[0]), T3);
00075    }
00076 
00077 }