787 lines
17 KiB
C
787 lines
17 KiB
C
// SPDX-License-Identifier: GPL-2.0 OR MIT
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/*
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* Copyright (C) 2016-2017 INRIA and Microsoft Corporation.
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* Copyright (C) 2018-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*
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* This is a machine-generated formally verified implementation of Curve25519
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* ECDH from: <https://github.com/mitls/hacl-star>. Though originally machine
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* generated, it has been tweaked to be suitable for use in the kernel. It is
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* optimized for 64-bit machines that can efficiently work with 128-bit
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* integer types.
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*/
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#include <asm/unaligned.h>
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#include <crypto/curve25519.h>
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#include <linux/string.h>
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static __always_inline u64 u64_eq_mask(u64 a, u64 b)
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{
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u64 x = a ^ b;
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u64 minus_x = ~x + (u64)1U;
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u64 x_or_minus_x = x | minus_x;
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u64 xnx = x_or_minus_x >> (u32)63U;
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u64 c = xnx - (u64)1U;
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return c;
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}
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static __always_inline u64 u64_gte_mask(u64 a, u64 b)
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{
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u64 x = a;
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u64 y = b;
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u64 x_xor_y = x ^ y;
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u64 x_sub_y = x - y;
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u64 x_sub_y_xor_y = x_sub_y ^ y;
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u64 q = x_xor_y | x_sub_y_xor_y;
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u64 x_xor_q = x ^ q;
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u64 x_xor_q_ = x_xor_q >> (u32)63U;
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u64 c = x_xor_q_ - (u64)1U;
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return c;
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}
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static __always_inline void modulo_carry_top(u64 *b)
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{
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u64 b4 = b[4];
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u64 b0 = b[0];
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u64 b4_ = b4 & 0x7ffffffffffffLLU;
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u64 b0_ = b0 + 19 * (b4 >> 51);
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b[4] = b4_;
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b[0] = b0_;
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}
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static __always_inline void fproduct_copy_from_wide_(u64 *output, u128 *input)
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{
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{
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u128 xi = input[0];
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output[0] = ((u64)(xi));
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}
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{
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u128 xi = input[1];
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output[1] = ((u64)(xi));
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}
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{
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u128 xi = input[2];
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output[2] = ((u64)(xi));
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}
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{
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u128 xi = input[3];
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output[3] = ((u64)(xi));
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}
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{
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u128 xi = input[4];
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output[4] = ((u64)(xi));
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}
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}
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static __always_inline void
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fproduct_sum_scalar_multiplication_(u128 *output, u64 *input, u64 s)
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{
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output[0] += (u128)input[0] * s;
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output[1] += (u128)input[1] * s;
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output[2] += (u128)input[2] * s;
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output[3] += (u128)input[3] * s;
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output[4] += (u128)input[4] * s;
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}
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static __always_inline void fproduct_carry_wide_(u128 *tmp)
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{
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{
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u32 ctr = 0;
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u128 tctr = tmp[ctr];
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u128 tctrp1 = tmp[ctr + 1];
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u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU;
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u128 c = ((tctr) >> (51));
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tmp[ctr] = ((u128)(r0));
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tmp[ctr + 1] = ((tctrp1) + (c));
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}
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{
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u32 ctr = 1;
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u128 tctr = tmp[ctr];
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u128 tctrp1 = tmp[ctr + 1];
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u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU;
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u128 c = ((tctr) >> (51));
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tmp[ctr] = ((u128)(r0));
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tmp[ctr + 1] = ((tctrp1) + (c));
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}
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{
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u32 ctr = 2;
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u128 tctr = tmp[ctr];
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u128 tctrp1 = tmp[ctr + 1];
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u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU;
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u128 c = ((tctr) >> (51));
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tmp[ctr] = ((u128)(r0));
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tmp[ctr + 1] = ((tctrp1) + (c));
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}
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{
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u32 ctr = 3;
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u128 tctr = tmp[ctr];
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u128 tctrp1 = tmp[ctr + 1];
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u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU;
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u128 c = ((tctr) >> (51));
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tmp[ctr] = ((u128)(r0));
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tmp[ctr + 1] = ((tctrp1) + (c));
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}
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}
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static __always_inline void fmul_shift_reduce(u64 *output)
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{
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u64 tmp = output[4];
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u64 b0;
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{
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u32 ctr = 5 - 0 - 1;
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u64 z = output[ctr - 1];
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output[ctr] = z;
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}
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{
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u32 ctr = 5 - 1 - 1;
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u64 z = output[ctr - 1];
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output[ctr] = z;
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}
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{
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u32 ctr = 5 - 2 - 1;
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u64 z = output[ctr - 1];
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output[ctr] = z;
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}
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{
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u32 ctr = 5 - 3 - 1;
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u64 z = output[ctr - 1];
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output[ctr] = z;
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}
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output[0] = tmp;
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b0 = output[0];
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output[0] = 19 * b0;
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}
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static __always_inline void fmul_mul_shift_reduce_(u128 *output, u64 *input,
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u64 *input21)
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{
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u32 i;
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u64 input2i;
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{
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u64 input2i = input21[0];
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fproduct_sum_scalar_multiplication_(output, input, input2i);
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fmul_shift_reduce(input);
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}
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{
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u64 input2i = input21[1];
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fproduct_sum_scalar_multiplication_(output, input, input2i);
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fmul_shift_reduce(input);
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}
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{
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u64 input2i = input21[2];
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fproduct_sum_scalar_multiplication_(output, input, input2i);
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fmul_shift_reduce(input);
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}
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{
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u64 input2i = input21[3];
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fproduct_sum_scalar_multiplication_(output, input, input2i);
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fmul_shift_reduce(input);
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}
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i = 4;
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input2i = input21[i];
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fproduct_sum_scalar_multiplication_(output, input, input2i);
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}
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static __always_inline void fmul_fmul(u64 *output, u64 *input, u64 *input21)
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{
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u64 tmp[5] = { input[0], input[1], input[2], input[3], input[4] };
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{
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u128 b4;
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u128 b0;
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u128 b4_;
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u128 b0_;
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u64 i0;
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u64 i1;
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u64 i0_;
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u64 i1_;
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u128 t[5] = { 0 };
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fmul_mul_shift_reduce_(t, tmp, input21);
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fproduct_carry_wide_(t);
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b4 = t[4];
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b0 = t[0];
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b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU))));
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b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51))))))));
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t[4] = b4_;
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t[0] = b0_;
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fproduct_copy_from_wide_(output, t);
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i0 = output[0];
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i1 = output[1];
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i0_ = i0 & 0x7ffffffffffffLLU;
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i1_ = i1 + (i0 >> 51);
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output[0] = i0_;
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output[1] = i1_;
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}
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}
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static __always_inline void fsquare_fsquare__(u128 *tmp, u64 *output)
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{
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u64 r0 = output[0];
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u64 r1 = output[1];
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u64 r2 = output[2];
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u64 r3 = output[3];
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u64 r4 = output[4];
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u64 d0 = r0 * 2;
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u64 d1 = r1 * 2;
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u64 d2 = r2 * 2 * 19;
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u64 d419 = r4 * 19;
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u64 d4 = d419 * 2;
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u128 s0 = ((((((u128)(r0) * (r0))) + (((u128)(d4) * (r1))))) +
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(((u128)(d2) * (r3))));
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u128 s1 = ((((((u128)(d0) * (r1))) + (((u128)(d4) * (r2))))) +
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(((u128)(r3 * 19) * (r3))));
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u128 s2 = ((((((u128)(d0) * (r2))) + (((u128)(r1) * (r1))))) +
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(((u128)(d4) * (r3))));
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u128 s3 = ((((((u128)(d0) * (r3))) + (((u128)(d1) * (r2))))) +
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(((u128)(r4) * (d419))));
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u128 s4 = ((((((u128)(d0) * (r4))) + (((u128)(d1) * (r3))))) +
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(((u128)(r2) * (r2))));
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tmp[0] = s0;
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tmp[1] = s1;
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tmp[2] = s2;
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tmp[3] = s3;
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tmp[4] = s4;
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}
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static __always_inline void fsquare_fsquare_(u128 *tmp, u64 *output)
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{
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u128 b4;
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u128 b0;
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u128 b4_;
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u128 b0_;
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u64 i0;
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u64 i1;
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u64 i0_;
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u64 i1_;
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fsquare_fsquare__(tmp, output);
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fproduct_carry_wide_(tmp);
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b4 = tmp[4];
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b0 = tmp[0];
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b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU))));
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b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51))))))));
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tmp[4] = b4_;
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tmp[0] = b0_;
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fproduct_copy_from_wide_(output, tmp);
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i0 = output[0];
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i1 = output[1];
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i0_ = i0 & 0x7ffffffffffffLLU;
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i1_ = i1 + (i0 >> 51);
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output[0] = i0_;
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output[1] = i1_;
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}
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static __always_inline void fsquare_fsquare_times_(u64 *output, u128 *tmp,
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u32 count1)
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{
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u32 i;
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fsquare_fsquare_(tmp, output);
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for (i = 1; i < count1; ++i)
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fsquare_fsquare_(tmp, output);
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}
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static __always_inline void fsquare_fsquare_times(u64 *output, u64 *input,
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u32 count1)
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{
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u128 t[5];
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memcpy(output, input, 5 * sizeof(*input));
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fsquare_fsquare_times_(output, t, count1);
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}
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static __always_inline void fsquare_fsquare_times_inplace(u64 *output,
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u32 count1)
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{
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u128 t[5];
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fsquare_fsquare_times_(output, t, count1);
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}
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static __always_inline void crecip_crecip(u64 *out, u64 *z)
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{
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u64 buf[20] = { 0 };
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u64 *a0 = buf;
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u64 *t00 = buf + 5;
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u64 *b0 = buf + 10;
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u64 *t01;
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u64 *b1;
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u64 *c0;
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u64 *a;
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u64 *t0;
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u64 *b;
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u64 *c;
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fsquare_fsquare_times(a0, z, 1);
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fsquare_fsquare_times(t00, a0, 2);
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fmul_fmul(b0, t00, z);
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fmul_fmul(a0, b0, a0);
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fsquare_fsquare_times(t00, a0, 1);
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fmul_fmul(b0, t00, b0);
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fsquare_fsquare_times(t00, b0, 5);
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t01 = buf + 5;
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b1 = buf + 10;
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c0 = buf + 15;
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fmul_fmul(b1, t01, b1);
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fsquare_fsquare_times(t01, b1, 10);
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fmul_fmul(c0, t01, b1);
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fsquare_fsquare_times(t01, c0, 20);
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fmul_fmul(t01, t01, c0);
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fsquare_fsquare_times_inplace(t01, 10);
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fmul_fmul(b1, t01, b1);
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fsquare_fsquare_times(t01, b1, 50);
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a = buf;
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t0 = buf + 5;
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b = buf + 10;
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c = buf + 15;
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fmul_fmul(c, t0, b);
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fsquare_fsquare_times(t0, c, 100);
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fmul_fmul(t0, t0, c);
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fsquare_fsquare_times_inplace(t0, 50);
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fmul_fmul(t0, t0, b);
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fsquare_fsquare_times_inplace(t0, 5);
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fmul_fmul(out, t0, a);
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}
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static __always_inline void fsum(u64 *a, u64 *b)
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{
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a[0] += b[0];
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a[1] += b[1];
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a[2] += b[2];
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a[3] += b[3];
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a[4] += b[4];
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}
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static __always_inline void fdifference(u64 *a, u64 *b)
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{
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u64 tmp[5] = { 0 };
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u64 b0;
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u64 b1;
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u64 b2;
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u64 b3;
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u64 b4;
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memcpy(tmp, b, 5 * sizeof(*b));
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b0 = tmp[0];
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b1 = tmp[1];
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b2 = tmp[2];
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b3 = tmp[3];
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b4 = tmp[4];
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tmp[0] = b0 + 0x3fffffffffff68LLU;
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tmp[1] = b1 + 0x3ffffffffffff8LLU;
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tmp[2] = b2 + 0x3ffffffffffff8LLU;
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tmp[3] = b3 + 0x3ffffffffffff8LLU;
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tmp[4] = b4 + 0x3ffffffffffff8LLU;
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{
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u64 xi = a[0];
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u64 yi = tmp[0];
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a[0] = yi - xi;
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}
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{
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u64 xi = a[1];
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u64 yi = tmp[1];
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a[1] = yi - xi;
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}
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{
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u64 xi = a[2];
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u64 yi = tmp[2];
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a[2] = yi - xi;
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}
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{
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u64 xi = a[3];
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u64 yi = tmp[3];
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a[3] = yi - xi;
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}
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{
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u64 xi = a[4];
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u64 yi = tmp[4];
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a[4] = yi - xi;
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}
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}
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static __always_inline void fscalar(u64 *output, u64 *b, u64 s)
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{
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u128 tmp[5];
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u128 b4;
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u128 b0;
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u128 b4_;
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u128 b0_;
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{
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u64 xi = b[0];
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tmp[0] = ((u128)(xi) * (s));
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}
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{
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u64 xi = b[1];
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tmp[1] = ((u128)(xi) * (s));
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}
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{
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u64 xi = b[2];
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tmp[2] = ((u128)(xi) * (s));
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}
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{
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u64 xi = b[3];
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tmp[3] = ((u128)(xi) * (s));
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}
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{
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u64 xi = b[4];
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tmp[4] = ((u128)(xi) * (s));
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}
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fproduct_carry_wide_(tmp);
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b4 = tmp[4];
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b0 = tmp[0];
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b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU))));
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b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51))))))));
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tmp[4] = b4_;
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tmp[0] = b0_;
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fproduct_copy_from_wide_(output, tmp);
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}
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static __always_inline void fmul(u64 *output, u64 *a, u64 *b)
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{
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fmul_fmul(output, a, b);
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}
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static __always_inline void crecip(u64 *output, u64 *input)
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{
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crecip_crecip(output, input);
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}
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static __always_inline void point_swap_conditional_step(u64 *a, u64 *b,
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u64 swap1, u32 ctr)
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{
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u32 i = ctr - 1;
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u64 ai = a[i];
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u64 bi = b[i];
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u64 x = swap1 & (ai ^ bi);
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u64 ai1 = ai ^ x;
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u64 bi1 = bi ^ x;
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a[i] = ai1;
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b[i] = bi1;
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}
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static __always_inline void point_swap_conditional5(u64 *a, u64 *b, u64 swap1)
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{
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point_swap_conditional_step(a, b, swap1, 5);
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point_swap_conditional_step(a, b, swap1, 4);
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point_swap_conditional_step(a, b, swap1, 3);
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point_swap_conditional_step(a, b, swap1, 2);
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point_swap_conditional_step(a, b, swap1, 1);
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}
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static __always_inline void point_swap_conditional(u64 *a, u64 *b, u64 iswap)
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{
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u64 swap1 = 0 - iswap;
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point_swap_conditional5(a, b, swap1);
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point_swap_conditional5(a + 5, b + 5, swap1);
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}
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static __always_inline void point_copy(u64 *output, u64 *input)
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{
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memcpy(output, input, 5 * sizeof(*input));
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memcpy(output + 5, input + 5, 5 * sizeof(*input));
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}
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static __always_inline void addanddouble_fmonty(u64 *pp, u64 *ppq, u64 *p,
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u64 *pq, u64 *qmqp)
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{
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u64 *qx = qmqp;
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u64 *x2 = pp;
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u64 *z2 = pp + 5;
|
|
u64 *x3 = ppq;
|
|
u64 *z3 = ppq + 5;
|
|
u64 *x = p;
|
|
u64 *z = p + 5;
|
|
u64 *xprime = pq;
|
|
u64 *zprime = pq + 5;
|
|
u64 buf[40] = { 0 };
|
|
u64 *origx = buf;
|
|
u64 *origxprime0 = buf + 5;
|
|
u64 *xxprime0;
|
|
u64 *zzprime0;
|
|
u64 *origxprime;
|
|
xxprime0 = buf + 25;
|
|
zzprime0 = buf + 30;
|
|
memcpy(origx, x, 5 * sizeof(*x));
|
|
fsum(x, z);
|
|
fdifference(z, origx);
|
|
memcpy(origxprime0, xprime, 5 * sizeof(*xprime));
|
|
fsum(xprime, zprime);
|
|
fdifference(zprime, origxprime0);
|
|
fmul(xxprime0, xprime, z);
|
|
fmul(zzprime0, x, zprime);
|
|
origxprime = buf + 5;
|
|
{
|
|
u64 *xx0;
|
|
u64 *zz0;
|
|
u64 *xxprime;
|
|
u64 *zzprime;
|
|
u64 *zzzprime;
|
|
xx0 = buf + 15;
|
|
zz0 = buf + 20;
|
|
xxprime = buf + 25;
|
|
zzprime = buf + 30;
|
|
zzzprime = buf + 35;
|
|
memcpy(origxprime, xxprime, 5 * sizeof(*xxprime));
|
|
fsum(xxprime, zzprime);
|
|
fdifference(zzprime, origxprime);
|
|
fsquare_fsquare_times(x3, xxprime, 1);
|
|
fsquare_fsquare_times(zzzprime, zzprime, 1);
|
|
fmul(z3, zzzprime, qx);
|
|
fsquare_fsquare_times(xx0, x, 1);
|
|
fsquare_fsquare_times(zz0, z, 1);
|
|
{
|
|
u64 *zzz;
|
|
u64 *xx;
|
|
u64 *zz;
|
|
u64 scalar;
|
|
zzz = buf + 10;
|
|
xx = buf + 15;
|
|
zz = buf + 20;
|
|
fmul(x2, xx, zz);
|
|
fdifference(zz, xx);
|
|
scalar = 121665;
|
|
fscalar(zzz, zz, scalar);
|
|
fsum(zzz, xx);
|
|
fmul(z2, zzz, zz);
|
|
}
|
|
}
|
|
}
|
|
|
|
static __always_inline void
|
|
ladder_smallloop_cmult_small_loop_step(u64 *nq, u64 *nqpq, u64 *nq2, u64 *nqpq2,
|
|
u64 *q, u8 byt)
|
|
{
|
|
u64 bit0 = (u64)(byt >> 7);
|
|
u64 bit;
|
|
point_swap_conditional(nq, nqpq, bit0);
|
|
addanddouble_fmonty(nq2, nqpq2, nq, nqpq, q);
|
|
bit = (u64)(byt >> 7);
|
|
point_swap_conditional(nq2, nqpq2, bit);
|
|
}
|
|
|
|
static __always_inline void
|
|
ladder_smallloop_cmult_small_loop_double_step(u64 *nq, u64 *nqpq, u64 *nq2,
|
|
u64 *nqpq2, u64 *q, u8 byt)
|
|
{
|
|
u8 byt1;
|
|
ladder_smallloop_cmult_small_loop_step(nq, nqpq, nq2, nqpq2, q, byt);
|
|
byt1 = byt << 1;
|
|
ladder_smallloop_cmult_small_loop_step(nq2, nqpq2, nq, nqpq, q, byt1);
|
|
}
|
|
|
|
static __always_inline void
|
|
ladder_smallloop_cmult_small_loop(u64 *nq, u64 *nqpq, u64 *nq2, u64 *nqpq2,
|
|
u64 *q, u8 byt, u32 i)
|
|
{
|
|
while (i--) {
|
|
ladder_smallloop_cmult_small_loop_double_step(nq, nqpq, nq2,
|
|
nqpq2, q, byt);
|
|
byt <<= 2;
|
|
}
|
|
}
|
|
|
|
static __always_inline void ladder_bigloop_cmult_big_loop(u8 *n1, u64 *nq,
|
|
u64 *nqpq, u64 *nq2,
|
|
u64 *nqpq2, u64 *q,
|
|
u32 i)
|
|
{
|
|
while (i--) {
|
|
u8 byte = n1[i];
|
|
ladder_smallloop_cmult_small_loop(nq, nqpq, nq2, nqpq2, q,
|
|
byte, 4);
|
|
}
|
|
}
|
|
|
|
static void ladder_cmult(u64 *result, u8 *n1, u64 *q)
|
|
{
|
|
u64 point_buf[40] = { 0 };
|
|
u64 *nq = point_buf;
|
|
u64 *nqpq = point_buf + 10;
|
|
u64 *nq2 = point_buf + 20;
|
|
u64 *nqpq2 = point_buf + 30;
|
|
point_copy(nqpq, q);
|
|
nq[0] = 1;
|
|
ladder_bigloop_cmult_big_loop(n1, nq, nqpq, nq2, nqpq2, q, 32);
|
|
point_copy(result, nq);
|
|
}
|
|
|
|
static __always_inline void format_fexpand(u64 *output, const u8 *input)
|
|
{
|
|
const u8 *x00 = input + 6;
|
|
const u8 *x01 = input + 12;
|
|
const u8 *x02 = input + 19;
|
|
const u8 *x0 = input + 24;
|
|
u64 i0, i1, i2, i3, i4, output0, output1, output2, output3, output4;
|
|
i0 = get_unaligned_le64(input);
|
|
i1 = get_unaligned_le64(x00);
|
|
i2 = get_unaligned_le64(x01);
|
|
i3 = get_unaligned_le64(x02);
|
|
i4 = get_unaligned_le64(x0);
|
|
output0 = i0 & 0x7ffffffffffffLLU;
|
|
output1 = i1 >> 3 & 0x7ffffffffffffLLU;
|
|
output2 = i2 >> 6 & 0x7ffffffffffffLLU;
|
|
output3 = i3 >> 1 & 0x7ffffffffffffLLU;
|
|
output4 = i4 >> 12 & 0x7ffffffffffffLLU;
|
|
output[0] = output0;
|
|
output[1] = output1;
|
|
output[2] = output2;
|
|
output[3] = output3;
|
|
output[4] = output4;
|
|
}
|
|
|
|
static __always_inline void format_fcontract_first_carry_pass(u64 *input)
|
|
{
|
|
u64 t0 = input[0];
|
|
u64 t1 = input[1];
|
|
u64 t2 = input[2];
|
|
u64 t3 = input[3];
|
|
u64 t4 = input[4];
|
|
u64 t1_ = t1 + (t0 >> 51);
|
|
u64 t0_ = t0 & 0x7ffffffffffffLLU;
|
|
u64 t2_ = t2 + (t1_ >> 51);
|
|
u64 t1__ = t1_ & 0x7ffffffffffffLLU;
|
|
u64 t3_ = t3 + (t2_ >> 51);
|
|
u64 t2__ = t2_ & 0x7ffffffffffffLLU;
|
|
u64 t4_ = t4 + (t3_ >> 51);
|
|
u64 t3__ = t3_ & 0x7ffffffffffffLLU;
|
|
input[0] = t0_;
|
|
input[1] = t1__;
|
|
input[2] = t2__;
|
|
input[3] = t3__;
|
|
input[4] = t4_;
|
|
}
|
|
|
|
static __always_inline void format_fcontract_first_carry_full(u64 *input)
|
|
{
|
|
format_fcontract_first_carry_pass(input);
|
|
modulo_carry_top(input);
|
|
}
|
|
|
|
static __always_inline void format_fcontract_second_carry_pass(u64 *input)
|
|
{
|
|
u64 t0 = input[0];
|
|
u64 t1 = input[1];
|
|
u64 t2 = input[2];
|
|
u64 t3 = input[3];
|
|
u64 t4 = input[4];
|
|
u64 t1_ = t1 + (t0 >> 51);
|
|
u64 t0_ = t0 & 0x7ffffffffffffLLU;
|
|
u64 t2_ = t2 + (t1_ >> 51);
|
|
u64 t1__ = t1_ & 0x7ffffffffffffLLU;
|
|
u64 t3_ = t3 + (t2_ >> 51);
|
|
u64 t2__ = t2_ & 0x7ffffffffffffLLU;
|
|
u64 t4_ = t4 + (t3_ >> 51);
|
|
u64 t3__ = t3_ & 0x7ffffffffffffLLU;
|
|
input[0] = t0_;
|
|
input[1] = t1__;
|
|
input[2] = t2__;
|
|
input[3] = t3__;
|
|
input[4] = t4_;
|
|
}
|
|
|
|
static __always_inline void format_fcontract_second_carry_full(u64 *input)
|
|
{
|
|
u64 i0;
|
|
u64 i1;
|
|
u64 i0_;
|
|
u64 i1_;
|
|
format_fcontract_second_carry_pass(input);
|
|
modulo_carry_top(input);
|
|
i0 = input[0];
|
|
i1 = input[1];
|
|
i0_ = i0 & 0x7ffffffffffffLLU;
|
|
i1_ = i1 + (i0 >> 51);
|
|
input[0] = i0_;
|
|
input[1] = i1_;
|
|
}
|
|
|
|
static __always_inline void format_fcontract_trim(u64 *input)
|
|
{
|
|
u64 a0 = input[0];
|
|
u64 a1 = input[1];
|
|
u64 a2 = input[2];
|
|
u64 a3 = input[3];
|
|
u64 a4 = input[4];
|
|
u64 mask0 = u64_gte_mask(a0, 0x7ffffffffffedLLU);
|
|
u64 mask1 = u64_eq_mask(a1, 0x7ffffffffffffLLU);
|
|
u64 mask2 = u64_eq_mask(a2, 0x7ffffffffffffLLU);
|
|
u64 mask3 = u64_eq_mask(a3, 0x7ffffffffffffLLU);
|
|
u64 mask4 = u64_eq_mask(a4, 0x7ffffffffffffLLU);
|
|
u64 mask = (((mask0 & mask1) & mask2) & mask3) & mask4;
|
|
u64 a0_ = a0 - (0x7ffffffffffedLLU & mask);
|
|
u64 a1_ = a1 - (0x7ffffffffffffLLU & mask);
|
|
u64 a2_ = a2 - (0x7ffffffffffffLLU & mask);
|
|
u64 a3_ = a3 - (0x7ffffffffffffLLU & mask);
|
|
u64 a4_ = a4 - (0x7ffffffffffffLLU & mask);
|
|
input[0] = a0_;
|
|
input[1] = a1_;
|
|
input[2] = a2_;
|
|
input[3] = a3_;
|
|
input[4] = a4_;
|
|
}
|
|
|
|
static __always_inline void format_fcontract_store(u8 *output, u64 *input)
|
|
{
|
|
u64 t0 = input[0];
|
|
u64 t1 = input[1];
|
|
u64 t2 = input[2];
|
|
u64 t3 = input[3];
|
|
u64 t4 = input[4];
|
|
u64 o0 = t1 << 51 | t0;
|
|
u64 o1 = t2 << 38 | t1 >> 13;
|
|
u64 o2 = t3 << 25 | t2 >> 26;
|
|
u64 o3 = t4 << 12 | t3 >> 39;
|
|
u8 *b0 = output;
|
|
u8 *b1 = output + 8;
|
|
u8 *b2 = output + 16;
|
|
u8 *b3 = output + 24;
|
|
put_unaligned_le64(o0, b0);
|
|
put_unaligned_le64(o1, b1);
|
|
put_unaligned_le64(o2, b2);
|
|
put_unaligned_le64(o3, b3);
|
|
}
|
|
|
|
static __always_inline void format_fcontract(u8 *output, u64 *input)
|
|
{
|
|
format_fcontract_first_carry_full(input);
|
|
format_fcontract_second_carry_full(input);
|
|
format_fcontract_trim(input);
|
|
format_fcontract_store(output, input);
|
|
}
|
|
|
|
static __always_inline void format_scalar_of_point(u8 *scalar, u64 *point)
|
|
{
|
|
u64 *x = point;
|
|
u64 *z = point + 5;
|
|
u64 buf[10] __aligned(32) = { 0 };
|
|
u64 *zmone = buf;
|
|
u64 *sc = buf + 5;
|
|
crecip(zmone, z);
|
|
fmul(sc, x, zmone);
|
|
format_fcontract(scalar, sc);
|
|
}
|
|
|
|
void curve25519_generic(u8 mypublic[CURVE25519_KEY_SIZE],
|
|
const u8 secret[CURVE25519_KEY_SIZE],
|
|
const u8 basepoint[CURVE25519_KEY_SIZE])
|
|
{
|
|
u64 buf0[10] __aligned(32) = { 0 };
|
|
u64 *x0 = buf0;
|
|
u64 *z = buf0 + 5;
|
|
u64 *q;
|
|
format_fexpand(x0, basepoint);
|
|
z[0] = 1;
|
|
q = buf0;
|
|
{
|
|
u8 e[32] __aligned(32) = { 0 };
|
|
u8 *scalar;
|
|
memcpy(e, secret, 32);
|
|
curve25519_clamp_secret(e);
|
|
scalar = e;
|
|
{
|
|
u64 buf[15] = { 0 };
|
|
u64 *nq = buf;
|
|
u64 *x = nq;
|
|
x[0] = 1;
|
|
ladder_cmult(nq, scalar, q);
|
|
format_scalar_of_point(mypublic, nq);
|
|
memzero_explicit(buf, sizeof(buf));
|
|
}
|
|
memzero_explicit(e, sizeof(e));
|
|
}
|
|
memzero_explicit(buf0, sizeof(buf0));
|
|
}
|