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/*
* (C) 2018 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/chacha.h>
#include <botan/internal/simd_avx2.h>
namespace Botan {
//static
BOTAN_FUNC_ISA("avx2")
void ChaCha::chacha_avx2_x8(uint8_t output[64*8], uint32_t state[16], size_t rounds)
{
SIMD_8x32::reset_registers();
BOTAN_ASSERT(rounds % 2 == 0, "Valid rounds");
const SIMD_8x32 CTR0 = SIMD_8x32(0, 1, 2, 3, 4, 5, 6, 7);
const uint32_t C = 0xFFFFFFFF - state[12];
const SIMD_8x32 CTR1 = SIMD_8x32(0, C < 1, C < 2, C < 3, C < 4, C < 5, C < 6, C < 7);
SIMD_8x32 R00 = SIMD_8x32::splat(state[ 0]);
SIMD_8x32 R01 = SIMD_8x32::splat(state[ 1]);
SIMD_8x32 R02 = SIMD_8x32::splat(state[ 2]);
SIMD_8x32 R03 = SIMD_8x32::splat(state[ 3]);
SIMD_8x32 R04 = SIMD_8x32::splat(state[ 4]);
SIMD_8x32 R05 = SIMD_8x32::splat(state[ 5]);
SIMD_8x32 R06 = SIMD_8x32::splat(state[ 6]);
SIMD_8x32 R07 = SIMD_8x32::splat(state[ 7]);
SIMD_8x32 R08 = SIMD_8x32::splat(state[ 8]);
SIMD_8x32 R09 = SIMD_8x32::splat(state[ 9]);
SIMD_8x32 R10 = SIMD_8x32::splat(state[10]);
SIMD_8x32 R11 = SIMD_8x32::splat(state[11]);
SIMD_8x32 R12 = SIMD_8x32::splat(state[12]) + CTR0;
SIMD_8x32 R13 = SIMD_8x32::splat(state[13]) + CTR1;
SIMD_8x32 R14 = SIMD_8x32::splat(state[14]);
SIMD_8x32 R15 = SIMD_8x32::splat(state[15]);
for(size_t r = 0; r != rounds / 2; ++r)
{
R00 += R04;
R01 += R05;
R02 += R06;
R03 += R07;
R12 ^= R00;
R13 ^= R01;
R14 ^= R02;
R15 ^= R03;
R12 = R12.rotl<16>();
R13 = R13.rotl<16>();
R14 = R14.rotl<16>();
R15 = R15.rotl<16>();
R08 += R12;
R09 += R13;
R10 += R14;
R11 += R15;
R04 ^= R08;
R05 ^= R09;
R06 ^= R10;
R07 ^= R11;
R04 = R04.rotl<12>();
R05 = R05.rotl<12>();
R06 = R06.rotl<12>();
R07 = R07.rotl<12>();
R00 += R04;
R01 += R05;
R02 += R06;
R03 += R07;
R12 ^= R00;
R13 ^= R01;
R14 ^= R02;
R15 ^= R03;
R12 = R12.rotl<8>();
R13 = R13.rotl<8>();
R14 = R14.rotl<8>();
R15 = R15.rotl<8>();
R08 += R12;
R09 += R13;
R10 += R14;
R11 += R15;
R04 ^= R08;
R05 ^= R09;
R06 ^= R10;
R07 ^= R11;
R04 = R04.rotl<7>();
R05 = R05.rotl<7>();
R06 = R06.rotl<7>();
R07 = R07.rotl<7>();
R00 += R05;
R01 += R06;
R02 += R07;
R03 += R04;
R15 ^= R00;
R12 ^= R01;
R13 ^= R02;
R14 ^= R03;
R15 = R15.rotl<16>();
R12 = R12.rotl<16>();
R13 = R13.rotl<16>();
R14 = R14.rotl<16>();
R10 += R15;
R11 += R12;
R08 += R13;
R09 += R14;
R05 ^= R10;
R06 ^= R11;
R07 ^= R08;
R04 ^= R09;
R05 = R05.rotl<12>();
R06 = R06.rotl<12>();
R07 = R07.rotl<12>();
R04 = R04.rotl<12>();
R00 += R05;
R01 += R06;
R02 += R07;
R03 += R04;
R15 ^= R00;
R12 ^= R01;
R13 ^= R02;
R14 ^= R03;
R15 = R15.rotl<8>();
R12 = R12.rotl<8>();
R13 = R13.rotl<8>();
R14 = R14.rotl<8>();
R10 += R15;
R11 += R12;
R08 += R13;
R09 += R14;
R05 ^= R10;
R06 ^= R11;
R07 ^= R08;
R04 ^= R09;
R05 = R05.rotl<7>();
R06 = R06.rotl<7>();
R07 = R07.rotl<7>();
R04 = R04.rotl<7>();
}
R00 += SIMD_8x32::splat(state[0]);
R01 += SIMD_8x32::splat(state[1]);
R02 += SIMD_8x32::splat(state[2]);
R03 += SIMD_8x32::splat(state[3]);
R04 += SIMD_8x32::splat(state[4]);
R05 += SIMD_8x32::splat(state[5]);
R06 += SIMD_8x32::splat(state[6]);
R07 += SIMD_8x32::splat(state[7]);
R08 += SIMD_8x32::splat(state[8]);
R09 += SIMD_8x32::splat(state[9]);
R10 += SIMD_8x32::splat(state[10]);
R11 += SIMD_8x32::splat(state[11]);
R12 += SIMD_8x32::splat(state[12]) + CTR0;
R13 += SIMD_8x32::splat(state[13]) + CTR1;
R14 += SIMD_8x32::splat(state[14]);
R15 += SIMD_8x32::splat(state[15]);
SIMD_8x32::transpose(R00, R01, R02, R03, R04, R05, R06, R07);
SIMD_8x32::transpose(R08, R09, R10, R11, R12, R13, R14, R15);
R00.store_le(output);
R08.store_le(output + 32*1);
R01.store_le(output + 32*2);
R09.store_le(output + 32*3);
R02.store_le(output + 32*4);
R10.store_le(output + 32*5);
R03.store_le(output + 32*6);
R11.store_le(output + 32*7);
R04.store_le(output + 32*8);
R12.store_le(output + 32*9);
R05.store_le(output + 32*10);
R13.store_le(output + 32*11);
R06.store_le(output + 32*12);
R14.store_le(output + 32*13);
R07.store_le(output + 32*14);
R15.store_le(output + 32*15);
SIMD_8x32::zero_registers();
state[12] += 8;
if(state[12] < 8)
state[13]++;
}
}