/*

* Hook for CLMUL/PMULL/VPMSUM

* (C) 2013,2017,2019,2020 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/internal/ghash.h>

#include <botan/internal/simd_32.h>

#if defined(BOTAN_SIMD_USE_SSE2)

   #include <immintrin.h>

   #include <wmmintrin.h>

#endif

namespace Botan {

namespace {

BOTAN_FORCE_INLINE SIMD_4x32 BOTAN_FUNC_ISA(BOTAN_VPERM_ISA) reverse_vector(const SIMD_4x32& in) {

#if defined(BOTAN_SIMD_USE_SSE2)

   const __m128i BSWAP_MASK = _mm_set_epi8(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);

   return SIMD_4x32(_mm_shuffle_epi8(in.raw(), BSWAP_MASK));

#elif defined(BOTAN_SIMD_USE_NEON)

   const uint8_t maskb[16] = {15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0};

   const uint8x16_t mask = vld1q_u8(maskb);

   return SIMD_4x32(vreinterpretq_u32_u8(vqtbl1q_u8(vreinterpretq_u8_u32(in.raw()), mask)));

#elif defined(BOTAN_SIMD_USE_ALTIVEC)

   const __vector unsigned char mask = {15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0};

   return SIMD_4x32(vec_perm(in.raw(), in.raw(), mask));

#endif

}

template <int M>

BOTAN_FORCE_INLINE SIMD_4x32 BOTAN_FUNC_ISA(BOTAN_CLMUL_ISA) clmul(const SIMD_4x32& H, const SIMD_4x32& x) {

   static_assert(M == 0x00 || M == 0x01 || M == 0x10 || M == 0x11, "Valid clmul mode");

#if defined(BOTAN_SIMD_USE_SSE2)

   return SIMD_4x32(_mm_clmulepi64_si128(x.raw(), H.raw(), M));

#elif defined(BOTAN_SIMD_USE_NEON)

   const uint64_t a = vgetq_lane_u64(vreinterpretq_u64_u32(x.raw()), M & 0x01);

   const uint64_t b = vgetq_lane_u64(vreinterpretq_u64_u32(H.raw()), (M & 0x10) >> 4);

   return SIMD_4x32(reinterpret_cast<uint32x4_t>(vmull_p64(a, b)));

#elif defined(BOTAN_SIMD_USE_ALTIVEC)

   const SIMD_4x32 mask_lo = SIMD_4x32(0, 0, 0xFFFFFFFF, 0xFFFFFFFF);

   SIMD_4x32 i1 = x;

   SIMD_4x32 i2 = H;

   if(M == 0x11) {

      i1 &= mask_lo;

      i2 &= mask_lo;

   } else if(M == 0x10) {

      i1 = i1.shift_elems_left<2>();

   } else if(M == 0x01) {

      i2 = i2.shift_elems_left<2>();

   } else if(M == 0x00) {

      i1 = mask_lo.andc(i1);

      i2 = mask_lo.andc(i2);

   }

   auto i1v = reinterpret_cast<__vector unsigned long long>(i1.raw());

   auto i2v = reinterpret_cast<__vector unsigned long long>(i2.raw());

   #if BOTAN_COMPILER_HAS_BUILTIN(__builtin_crypto_vpmsumd)

   auto rv = __builtin_crypto_vpmsumd(i1v, i2v);

   #else

   auto rv = __builtin_altivec_crypto_vpmsumd(i1v, i2v);

   #endif

   return SIMD_4x32(reinterpret_cast<__vector unsigned int>(rv));

#endif

}

Unexecuted instantiation: ghash_cpu.cpp:Botan::SIMD_4x32 Botan::(anonymous namespace)::clmul<17>(Botan::SIMD_4x32 const&, Botan::SIMD_4x32 const&)

Unexecuted instantiation: ghash_cpu.cpp:Botan::SIMD_4x32 Botan::(anonymous namespace)::clmul<16>(Botan::SIMD_4x32 const&, Botan::SIMD_4x32 const&)

Unexecuted instantiation: ghash_cpu.cpp:Botan::SIMD_4x32 Botan::(anonymous namespace)::clmul<1>(Botan::SIMD_4x32 const&, Botan::SIMD_4x32 const&)

Unexecuted instantiation: ghash_cpu.cpp:Botan::SIMD_4x32 Botan::(anonymous namespace)::clmul<0>(Botan::SIMD_4x32 const&, Botan::SIMD_4x32 const&)

inline SIMD_4x32 gcm_reduce(const SIMD_4x32& B0, const SIMD_4x32& B1) {

   SIMD_4x32 X0 = B1.shr<31>();

   SIMD_4x32 X1 = B1.shl<1>();

   SIMD_4x32 X2 = B0.shr<31>();

   SIMD_4x32 X3 = B0.shl<1>();

   X3 |= X0.shift_elems_right<3>();

   X3 |= X2.shift_elems_left<1>();

   X1 |= X0.shift_elems_left<1>();

   X0 = X1.shl<31>() ^ X1.shl<30>() ^ X1.shl<25>();

   X1 ^= X0.shift_elems_left<3>();

   X0 = X1 ^ X3 ^ X0.shift_elems_right<1>();

   X0 ^= X1.shr<7>() ^ X1.shr<2>() ^ X1.shr<1>();

   return X0;

}

inline SIMD_4x32 BOTAN_FUNC_ISA(BOTAN_CLMUL_ISA) gcm_multiply(const SIMD_4x32& H, const SIMD_4x32& x) {

   SIMD_4x32 T0 = clmul<0x11>(H, x);

   SIMD_4x32 T1 = clmul<0x10>(H, x);

   SIMD_4x32 T2 = clmul<0x01>(H, x);

   SIMD_4x32 T3 = clmul<0x00>(H, x);

   T1 ^= T2;

   T0 ^= T1.shift_elems_right<2>();

   T3 ^= T1.shift_elems_left<2>();

   return gcm_reduce(T0, T3);

}

inline SIMD_4x32 BOTAN_FUNC_ISA(BOTAN_CLMUL_ISA) gcm_multiply_x4(const SIMD_4x32& H1,

                                                                 const SIMD_4x32& H2,

                                                                 const SIMD_4x32& H3,

                                                                 const SIMD_4x32& H4,

                                                                 const SIMD_4x32& X1,

                                                                 const SIMD_4x32& X2,

                                                                 const SIMD_4x32& X3,

                                                                 const SIMD_4x32& X4) {

   /*

   * Mutiply with delayed reduction, algorithm by Krzysztof Jankowski

   * and Pierre Laurent of Intel

   */

   const SIMD_4x32 lo = (clmul<0x00>(H1, X1) ^ clmul<0x00>(H2, X2)) ^ (clmul<0x00>(H3, X3) ^ clmul<0x00>(H4, X4));

   const SIMD_4x32 hi = (clmul<0x11>(H1, X1) ^ clmul<0x11>(H2, X2)) ^ (clmul<0x11>(H3, X3) ^ clmul<0x11>(H4, X4));

   SIMD_4x32 T;

   T ^= clmul<0x00>(H1 ^ H1.shift_elems_right<2>(), X1 ^ X1.shift_elems_right<2>());

   T ^= clmul<0x00>(H2 ^ H2.shift_elems_right<2>(), X2 ^ X2.shift_elems_right<2>());

   T ^= clmul<0x00>(H3 ^ H3.shift_elems_right<2>(), X3 ^ X3.shift_elems_right<2>());

   T ^= clmul<0x00>(H4 ^ H4.shift_elems_right<2>(), X4 ^ X4.shift_elems_right<2>());

   T ^= lo;

   T ^= hi;

   return gcm_reduce(hi ^ T.shift_elems_right<2>(), lo ^ T.shift_elems_left<2>());

}

}  // namespace

BOTAN_FUNC_ISA(BOTAN_VPERM_ISA) void GHASH::ghash_precompute_cpu(const uint8_t H_bytes[16], uint64_t H_pow[4 * 2]) {

   const SIMD_4x32 H1 = reverse_vector(SIMD_4x32::load_le(H_bytes));

   const SIMD_4x32 H2 = gcm_multiply(H1, H1);

   const SIMD_4x32 H3 = gcm_multiply(H1, H2);

   const SIMD_4x32 H4 = gcm_multiply(H2, H2);

   H1.store_le(H_pow);

   H2.store_le(H_pow + 2);

   H3.store_le(H_pow + 4);

   H4.store_le(H_pow + 6);

}

BOTAN_FUNC_ISA(BOTAN_VPERM_ISA)

void GHASH::ghash_multiply_cpu(uint8_t x[16], const uint64_t H_pow[8], const uint8_t input[], size_t blocks) {

   /*

   * Algorithms 1 and 5 from Intel's CLMUL guide

   */

   const SIMD_4x32 H1 = SIMD_4x32::load_le(H_pow);

   SIMD_4x32 a = reverse_vector(SIMD_4x32::load_le(x));

   if(blocks >= 4) {

      const SIMD_4x32 H2 = SIMD_4x32::load_le(H_pow + 2);

      const SIMD_4x32 H3 = SIMD_4x32::load_le(H_pow + 4);

      const SIMD_4x32 H4 = SIMD_4x32::load_le(H_pow + 6);

      while(blocks >= 4) {

         const SIMD_4x32 m0 = reverse_vector(SIMD_4x32::load_le(input));

         const SIMD_4x32 m1 = reverse_vector(SIMD_4x32::load_le(input + 16 * 1));

         const SIMD_4x32 m2 = reverse_vector(SIMD_4x32::load_le(input + 16 * 2));

         const SIMD_4x32 m3 = reverse_vector(SIMD_4x32::load_le(input + 16 * 3));

         a ^= m0;

         a = gcm_multiply_x4(H1, H2, H3, H4, m3, m2, m1, a);

         input += 4 * 16;

         blocks -= 4;

      }

   }

   for(size_t i = 0; i != blocks; ++i) {

      const SIMD_4x32 m = reverse_vector(SIMD_4x32::load_le(input + 16 * i));

      a ^= m;

      a = gcm_multiply(H1, a);

   }

   a = reverse_vector(a);

   a.store_le(x);

}

}  // namespace Botan