#define VEC8_ROT(A, IMM) \
    _mm256_or_si256(_mm256_slli_epi32(A, IMM), _mm256_srli_epi32(A, (32 - IMM)))

/* implements a vector quarter round by-the-book (naive!) */
#define VEC8_QUARTERROUND_NAIVE(A, B, C, D) \
    x_##A = _mm256_add_epi32(x_##A, x_##B); \
    t_##A = _mm256_xor_si256(x_##D, x_##A); \
    x_##D = VEC8_ROT(t_##A, 16);            \
    x_##C = _mm256_add_epi32(x_##C, x_##D); \
    t_##C = _mm256_xor_si256(x_##B, x_##C); \
    x_##B = VEC8_ROT(t_##C, 12);            \
    x_##A = _mm256_add_epi32(x_##A, x_##B); \
    t_##A = _mm256_xor_si256(x_##D, x_##A); \
    x_##D = VEC8_ROT(t_##A, 8);             \
    x_##C = _mm256_add_epi32(x_##C, x_##D); \
    t_##C = _mm256_xor_si256(x_##B, x_##C); \
    x_##B = VEC8_ROT(t_##C, 7)

/* same, but replace 2 of the shift/shift/or "rotation" by byte shuffles (8 &
 * 16) (better) */
#define VEC8_QUARTERROUND_SHUFFLE(A, B, C, D)  \
    x_##A = _mm256_add_epi32(x_##A, x_##B);    \
    t_##A = _mm256_xor_si256(x_##D, x_##A);    \
    x_##D = _mm256_shuffle_epi8(t_##A, rot16); \
    x_##C = _mm256_add_epi32(x_##C, x_##D);    \
    t_##C = _mm256_xor_si256(x_##B, x_##C);    \
    x_##B = VEC8_ROT(t_##C, 12);               \
    x_##A = _mm256_add_epi32(x_##A, x_##B);    \
    t_##A = _mm256_xor_si256(x_##D, x_##A);    \
    x_##D = _mm256_shuffle_epi8(t_##A, rot8);  \
    x_##C = _mm256_add_epi32(x_##C, x_##D);    \
    t_##C = _mm256_xor_si256(x_##B, x_##C);    \
    x_##B = VEC8_ROT(t_##C, 7)

/* same, but replace 2 of the shift/shift/or "rotation" by byte & word shuffles
 * (8 & 16) (not as good as previous) */
#define VEC8_QUARTERROUND_SHUFFLE2(A, B, C, D)                                 \
    x_##A = _mm256_add_epi32(x_##A, x_##B);                                    \
    t_##A = _mm256_xor_si256(x_##D, x_##A);                                    \
    x_##D = _mm256_shufflehi_epi16(_mm256_shufflelo_epi16(t_##A, 0xb1), 0xb1); \
    x_##C = _mm256_add_epi32(x_##C, x_##D);                                    \
    t_##C = _mm256_xor_si256(x_##B, x_##C);                                    \
    x_##B = VEC8_ROT(t_##C, 12);                                               \
    x_##A = _mm256_add_epi32(x_##A, x_##B);                                    \
    t_##A = _mm256_xor_si256(x_##D, x_##A);                                    \
    x_##D = _mm256_shuffle_epi8(t_##A, rot8);                                  \
    x_##C = _mm256_add_epi32(x_##C, x_##D);                                    \
    t_##C = _mm256_xor_si256(x_##B, x_##C);                                    \
    x_##B = VEC8_ROT(t_##C, 7)

#define VEC8_QUARTERROUND(A, B, C, D) VEC8_QUARTERROUND_SHUFFLE(A, B, C, D)

#define VEC8_LINE1(A, B, C, D)              \
    x_##A = _mm256_add_epi32(x_##A, x_##B); \
    x_##D = _mm256_shuffle_epi8(_mm256_xor_si256(x_##D, x_##A), rot16)
#define VEC8_LINE2(A, B, C, D)              \
    x_##C = _mm256_add_epi32(x_##C, x_##D); \
    x_##B = VEC8_ROT(_mm256_xor_si256(x_##B, x_##C), 12)
#define VEC8_LINE3(A, B, C, D)              \
    x_##A = _mm256_add_epi32(x_##A, x_##B); \
    x_##D = _mm256_shuffle_epi8(_mm256_xor_si256(x_##D, x_##A), rot8)
#define VEC8_LINE4(A, B, C, D)              \
    x_##C = _mm256_add_epi32(x_##C, x_##D); \
    x_##B = VEC8_ROT(_mm256_xor_si256(x_##B, x_##C), 7)

#define VEC8_ROUND_SEQ(A1, B1, C1, D1, A2, B2, C2, D2, A3, B3, C3, D3, A4, B4, \
                       C4, D4)                                                 \
    VEC8_LINE1(A1, B1, C1, D1);                                                \
    VEC8_LINE1(A2, B2, C2, D2);                                                \
    VEC8_LINE1(A3, B3, C3, D3);                                                \
    VEC8_LINE1(A4, B4, C4, D4);                                                \
    VEC8_LINE2(A1, B1, C1, D1);                                                \
    VEC8_LINE2(A2, B2, C2, D2);                                                \
    VEC8_LINE2(A3, B3, C3, D3);                                                \
    VEC8_LINE2(A4, B4, C4, D4);                                                \
    VEC8_LINE3(A1, B1, C1, D1);                                                \
    VEC8_LINE3(A2, B2, C2, D2);                                                \
    VEC8_LINE3(A3, B3, C3, D3);                                                \
    VEC8_LINE3(A4, B4, C4, D4);                                                \
    VEC8_LINE4(A1, B1, C1, D1);                                                \
    VEC8_LINE4(A2, B2, C2, D2);                                                \
    VEC8_LINE4(A3, B3, C3, D3);                                                \
    VEC8_LINE4(A4, B4, C4, D4)

#define VEC8_ROUND_HALF(A1, B1, C1, D1, A2, B2, C2, D2, A3, B3, C3, D3, A4, \
                        B4, C4, D4)                                         \
    VEC8_LINE1(A1, B1, C1, D1);                                             \
    VEC8_LINE1(A2, B2, C2, D2);                                             \
    VEC8_LINE2(A1, B1, C1, D1);                                             \
    VEC8_LINE2(A2, B2, C2, D2);                                             \
    VEC8_LINE3(A1, B1, C1, D1);                                             \
    VEC8_LINE3(A2, B2, C2, D2);                                             \
    VEC8_LINE4(A1, B1, C1, D1);                                             \
    VEC8_LINE4(A2, B2, C2, D2);                                             \
    VEC8_LINE1(A3, B3, C3, D3);                                             \
    VEC8_LINE1(A4, B4, C4, D4);                                             \
    VEC8_LINE2(A3, B3, C3, D3);                                             \
    VEC8_LINE2(A4, B4, C4, D4);                                             \
    VEC8_LINE3(A3, B3, C3, D3);                                             \
    VEC8_LINE3(A4, B4, C4, D4);                                             \
    VEC8_LINE4(A3, B3, C3, D3);                                             \
    VEC8_LINE4(A4, B4, C4, D4)

#define VEC8_ROUND_HALFANDHALF(A1, B1, C1, D1, A2, B2, C2, D2, A3, B3, C3, D3, \
                               A4, B4, C4, D4)                                 \
    VEC8_LINE1(A1, B1, C1, D1);                                                \
    VEC8_LINE1(A2, B2, C2, D2);                                                \
    VEC8_LINE2(A1, B1, C1, D1);                                                \
    VEC8_LINE2(A2, B2, C2, D2);                                                \
    VEC8_LINE1(A3, B3, C3, D3);                                                \
    VEC8_LINE1(A4, B4, C4, D4);                                                \
    VEC8_LINE2(A3, B3, C3, D3);                                                \
    VEC8_LINE2(A4, B4, C4, D4);                                                \
    VEC8_LINE3(A1, B1, C1, D1);                                                \
    VEC8_LINE3(A2, B2, C2, D2);                                                \
    VEC8_LINE4(A1, B1, C1, D1);                                                \
    VEC8_LINE4(A2, B2, C2, D2);                                                \
    VEC8_LINE3(A3, B3, C3, D3);                                                \
    VEC8_LINE3(A4, B4, C4, D4);                                                \
    VEC8_LINE4(A3, B3, C3, D3);                                                \
    VEC8_LINE4(A4, B4, C4, D4)

#define VEC8_ROUND(A1, B1, C1, D1, A2, B2, C2, D2, A3, B3, C3, D3, A4, B4, C4, \
                   D4)                                                         \
    VEC8_ROUND_SEQ(A1, B1, C1, D1, A2, B2, C2, D2, A3, B3, C3, D3, A4, B4, C4, \
                   D4)

if (bytes >= 512) {
    /* constant for shuffling bytes (replacing multiple-of-8 rotates) */
    __m256i rot16 =
        _mm256_set_epi8(13, 12, 15, 14, 9, 8, 11, 10, 5, 4, 7, 6, 1, 0, 3, 2,
                        13, 12, 15, 14, 9, 8, 11, 10, 5, 4, 7, 6, 1, 0, 3, 2);
    __m256i rot8 =
        _mm256_set_epi8(14, 13, 12, 15, 10, 9, 8, 11, 6, 5, 4, 7, 2, 1, 0, 3,
                        14, 13, 12, 15, 10, 9, 8, 11, 6, 5, 4, 7, 2, 1, 0, 3);
    uint32_t in12, in13;

    /* the naive way seems as fast (if not a bit faster) than the vector way */
    __m256i x_0  = _mm256_set1_epi32(x[0]);
    __m256i x_1  = _mm256_set1_epi32(x[1]);
    __m256i x_2  = _mm256_set1_epi32(x[2]);
    __m256i x_3  = _mm256_set1_epi32(x[3]);
    __m256i x_4  = _mm256_set1_epi32(x[4]);
    __m256i x_5  = _mm256_set1_epi32(x[5]);
    __m256i x_6  = _mm256_set1_epi32(x[6]);
    __m256i x_7  = _mm256_set1_epi32(x[7]);
    __m256i x_8  = _mm256_set1_epi32(x[8]);
    __m256i x_9  = _mm256_set1_epi32(x[9]);
    __m256i x_10 = _mm256_set1_epi32(x[10]);
    __m256i x_11 = _mm256_set1_epi32(x[11]);
    __m256i x_12;
    __m256i x_13;
    __m256i x_14 = _mm256_set1_epi32(x[14]);
    __m256i x_15 = _mm256_set1_epi32(x[15]);

    __m256i orig0  = x_0;
    __m256i orig1  = x_1;
    __m256i orig2  = x_2;
    __m256i orig3  = x_3;
    __m256i orig4  = x_4;
    __m256i orig5  = x_5;
    __m256i orig6  = x_6;
    __m256i orig7  = x_7;
    __m256i orig8  = x_8;
    __m256i orig9  = x_9;
    __m256i orig10 = x_10;
    __m256i orig11 = x_11;
    __m256i orig12;
    __m256i orig13;
    __m256i orig14 = x_14;
    __m256i orig15 = x_15;
    __m256i t_0, t_1, t_2, t_3, t_4, t_5, t_6, t_7, t_8, t_9, t_10, t_11, t_12,
        t_13, t_14, t_15;

    while (bytes >= 512) {
        const __m256i addv12  = _mm256_set_epi64x(3, 2, 1, 0);
        const __m256i addv13  = _mm256_set_epi64x(7, 6, 5, 4);
        const __m256i permute = _mm256_set_epi32(7, 6, 3, 2, 5, 4, 1, 0);
        __m256i       t12, t13;

        uint64_t in1213;
        int      i;

        x_0  = orig0;
        x_1  = orig1;
        x_2  = orig2;
        x_3  = orig3;
        x_4  = orig4;
        x_5  = orig5;
        x_6  = orig6;
        x_7  = orig7;
        x_8  = orig8;
        x_9  = orig9;
        x_10 = orig10;
        x_11 = orig11;
        x_14 = orig14;
        x_15 = orig15;

        in12   = x[12];
        in13   = x[13];
        in1213 = ((uint64_t) in12) | (((uint64_t) in13) << 32);
        x_12   = x_13 = _mm256_broadcastq_epi64(_mm_cvtsi64_si128(in1213));

        t12 = _mm256_add_epi64(addv12, x_12);
        t13 = _mm256_add_epi64(addv13, x_13);

        x_12 = _mm256_unpacklo_epi32(t12, t13);
        x_13 = _mm256_unpackhi_epi32(t12, t13);

        t12 = _mm256_unpacklo_epi32(x_12, x_13);
        t13 = _mm256_unpackhi_epi32(x_12, x_13);

        /* required because unpack* are intra-lane */
        x_12 = _mm256_permutevar8x32_epi32(t12, permute);
        x_13 = _mm256_permutevar8x32_epi32(t13, permute);

        orig12 = x_12;
        orig13 = x_13;

        in1213 += 8;

        x[12] = in1213 & 0xFFFFFFFF;
        x[13] = (in1213 >> 32) & 0xFFFFFFFF;

        for (i = 0; i < ROUNDS; i += 2) {
            VEC8_ROUND(0, 4, 8, 12, 1, 5, 9, 13, 2, 6, 10, 14, 3, 7, 11, 15);
            VEC8_ROUND(0, 5, 10, 15, 1, 6, 11, 12, 2, 7, 8, 13, 3, 4, 9, 14);
        }

#define ONEQUAD_TRANSPOSE(A, B, C, D)                              \
    {                                                              \
        __m128i t0, t1, t2, t3;                                    \
        x_##A = _mm256_add_epi32(x_##A, orig##A);                  \
        x_##B = _mm256_add_epi32(x_##B, orig##B);                  \
        x_##C = _mm256_add_epi32(x_##C, orig##C);                  \
        x_##D = _mm256_add_epi32(x_##D, orig##D);                  \
        t_##A = _mm256_unpacklo_epi32(x_##A, x_##B);               \
        t_##B = _mm256_unpacklo_epi32(x_##C, x_##D);               \
        t_##C = _mm256_unpackhi_epi32(x_##A, x_##B);               \
        t_##D = _mm256_unpackhi_epi32(x_##C, x_##D);               \
        x_##A = _mm256_unpacklo_epi64(t_##A, t_##B);               \
        x_##B = _mm256_unpackhi_epi64(t_##A, t_##B);               \
        x_##C = _mm256_unpacklo_epi64(t_##C, t_##D);               \
        x_##D = _mm256_unpackhi_epi64(t_##C, t_##D);               \
        t0    = _mm_xor_si128(_mm256_extracti128_si256(x_##A, 0),  \
                           _mm_loadu_si128((__m128i*) (m + 0)));   \
        _mm_storeu_si128((__m128i*) (c + 0), t0);                  \
        t1 = _mm_xor_si128(_mm256_extracti128_si256(x_##B, 0),     \
                           _mm_loadu_si128((__m128i*) (m + 64)));  \
        _mm_storeu_si128((__m128i*) (c + 64), t1);                 \
        t2 = _mm_xor_si128(_mm256_extracti128_si256(x_##C, 0),     \
                           _mm_loadu_si128((__m128i*) (m + 128))); \
        _mm_storeu_si128((__m128i*) (c + 128), t2);                \
        t3 = _mm_xor_si128(_mm256_extracti128_si256(x_##D, 0),     \
                           _mm_loadu_si128((__m128i*) (m + 192))); \
        _mm_storeu_si128((__m128i*) (c + 192), t3);                \
        t0 = _mm_xor_si128(_mm256_extracti128_si256(x_##A, 1),     \
                           _mm_loadu_si128((__m128i*) (m + 256))); \
        _mm_storeu_si128((__m128i*) (c + 256), t0);                \
        t1 = _mm_xor_si128(_mm256_extracti128_si256(x_##B, 1),     \
                           _mm_loadu_si128((__m128i*) (m + 320))); \
        _mm_storeu_si128((__m128i*) (c + 320), t1);                \
        t2 = _mm_xor_si128(_mm256_extracti128_si256(x_##C, 1),     \
                           _mm_loadu_si128((__m128i*) (m + 384))); \
        _mm_storeu_si128((__m128i*) (c + 384), t2);                \
        t3 = _mm_xor_si128(_mm256_extracti128_si256(x_##D, 1),     \
                           _mm_loadu_si128((__m128i*) (m + 448))); \
        _mm_storeu_si128((__m128i*) (c + 448), t3);                \
    }

#define ONEQUAD(A, B, C, D) ONEQUAD_TRANSPOSE(A, B, C, D)

#define ONEQUAD_UNPCK(A, B, C, D)                    \
    {                                                \
        x_##A = _mm256_add_epi32(x_##A, orig##A);    \
        x_##B = _mm256_add_epi32(x_##B, orig##B);    \
        x_##C = _mm256_add_epi32(x_##C, orig##C);    \
        x_##D = _mm256_add_epi32(x_##D, orig##D);    \
        t_##A = _mm256_unpacklo_epi32(x_##A, x_##B); \
        t_##B = _mm256_unpacklo_epi32(x_##C, x_##D); \
        t_##C = _mm256_unpackhi_epi32(x_##A, x_##B); \
        t_##D = _mm256_unpackhi_epi32(x_##C, x_##D); \
        x_##A = _mm256_unpacklo_epi64(t_##A, t_##B); \
        x_##B = _mm256_unpackhi_epi64(t_##A, t_##B); \
        x_##C = _mm256_unpacklo_epi64(t_##C, t_##D); \
        x_##D = _mm256_unpackhi_epi64(t_##C, t_##D); \
    }

#define ONEOCTO(A, B, C, D, A2, B2, C2, D2)                                    \
    {                                                                          \
        ONEQUAD_UNPCK(A, B, C, D);                                             \
        ONEQUAD_UNPCK(A2, B2, C2, D2);                                         \
        t_##A  = _mm256_permute2x128_si256(x_##A, x_##A2, 0x20);               \
        t_##A2 = _mm256_permute2x128_si256(x_##A, x_##A2, 0x31);               \
        t_##B  = _mm256_permute2x128_si256(x_##B, x_##B2, 0x20);               \
        t_##B2 = _mm256_permute2x128_si256(x_##B, x_##B2, 0x31);               \
        t_##C  = _mm256_permute2x128_si256(x_##C, x_##C2, 0x20);               \
        t_##C2 = _mm256_permute2x128_si256(x_##C, x_##C2, 0x31);               \
        t_##D  = _mm256_permute2x128_si256(x_##D, x_##D2, 0x20);               \
        t_##D2 = _mm256_permute2x128_si256(x_##D, x_##D2, 0x31);               \
        t_##A =                                                                \
            _mm256_xor_si256(t_##A, _mm256_loadu_si256((__m256i*) (m + 0)));   \
        t_##B =                                                                \
            _mm256_xor_si256(t_##B, _mm256_loadu_si256((__m256i*) (m + 64)));  \
        t_##C =                                                                \
            _mm256_xor_si256(t_##C, _mm256_loadu_si256((__m256i*) (m + 128))); \
        t_##D =                                                                \
            _mm256_xor_si256(t_##D, _mm256_loadu_si256((__m256i*) (m + 192))); \
        t_##A2 = _mm256_xor_si256(t_##A2,                                      \
                                  _mm256_loadu_si256((__m256i*) (m + 256)));   \
        t_##B2 = _mm256_xor_si256(t_##B2,                                      \
                                  _mm256_loadu_si256((__m256i*) (m + 320)));   \
        t_##C2 = _mm256_xor_si256(t_##C2,                                      \
                                  _mm256_loadu_si256((__m256i*) (m + 384)));   \
        t_##D2 = _mm256_xor_si256(t_##D2,                                      \
                                  _mm256_loadu_si256((__m256i*) (m + 448)));   \
        _mm256_storeu_si256((__m256i*) (c + 0), t_##A);                        \
        _mm256_storeu_si256((__m256i*) (c + 64), t_##B);                       \
        _mm256_storeu_si256((__m256i*) (c + 128), t_##C);                      \
        _mm256_storeu_si256((__m256i*) (c + 192), t_##D);                      \
        _mm256_storeu_si256((__m256i*) (c + 256), t_##A2);                     \
        _mm256_storeu_si256((__m256i*) (c + 320), t_##B2);                     \
        _mm256_storeu_si256((__m256i*) (c + 384), t_##C2);                     \
        _mm256_storeu_si256((__m256i*) (c + 448), t_##D2);                     \
    }

        ONEOCTO(0, 1, 2, 3, 4, 5, 6, 7);
        m += 32;
        c += 32;
        ONEOCTO(8, 9, 10, 11, 12, 13, 14, 15);
        m -= 32;
        c -= 32;

#undef ONEQUAD
#undef ONEQUAD_TRANSPOSE
#undef ONEQUAD_UNPCK
#undef ONEOCTO

        bytes -= 512;
        c += 512;
        m += 512;
    }
}
#undef VEC8_ROT
#undef VEC8_QUARTERROUND
#undef VEC8_QUARTERROUND_NAIVE
#undef VEC8_QUARTERROUND_SHUFFLE
#undef VEC8_QUARTERROUND_SHUFFLE2
#undef VEC8_LINE1
#undef VEC8_LINE2
#undef VEC8_LINE3
#undef VEC8_LINE4
#undef VEC8_ROUND
#undef VEC8_ROUND_SEQ
#undef VEC8_ROUND_HALF
#undef VEC8_ROUND_HALFANDHALF