/*
 * Copyright (c) 2024 Lucas Gabriel Vuotto <lucas@lgv5.net>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stddef.h>
#include <stdint.h>

#include "impl_sha512.h"
#include "util.h"


static const uint64_t K[SHA512_ROUNDS] = {
	0x428a2f98d728ae22, 0x7137449123ef65cd,
	0xb5c0fbcfec4d3b2f, 0xe9b5dba58189dbbc,
	0x3956c25bf348b538, 0x59f111f1b605d019,
	0x923f82a4af194f9b, 0xab1c5ed5da6d8118,
	0xd807aa98a3030242, 0x12835b0145706fbe,
	0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2,
	0x72be5d74f27b896f, 0x80deb1fe3b1696b1,
	0x9bdc06a725c71235, 0xc19bf174cf692694,
	0xe49b69c19ef14ad2, 0xefbe4786384f25e3,
	0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65,
	0x2de92c6f592b0275, 0x4a7484aa6ea6e483,
	0x5cb0a9dcbd41fbd4, 0x76f988da831153b5,
	0x983e5152ee66dfab, 0xa831c66d2db43210,
	0xb00327c898fb213f, 0xbf597fc7beef0ee4,
	0xc6e00bf33da88fc2, 0xd5a79147930aa725,
	0x06ca6351e003826f, 0x142929670a0e6e70,
	0x27b70a8546d22ffc, 0x2e1b21385c26c926,
	0x4d2c6dfc5ac42aed, 0x53380d139d95b3df,
	0x650a73548baf63de, 0x766a0abb3c77b2a8,
	0x81c2c92e47edaee6, 0x92722c851482353b,
	0xa2bfe8a14cf10364, 0xa81a664bbc423001,
	0xc24b8b70d0f89791, 0xc76c51a30654be30,
	0xd192e819d6ef5218, 0xd69906245565a910,
	0xf40e35855771202a, 0x106aa07032bbd1b8,
	0x19a4c116b8d2d0c8, 0x1e376c085141ab53,
	0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8,
	0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb,
	0x5b9cca4f7763e373, 0x682e6ff3d6b2b8a3,
	0x748f82ee5defb2fc, 0x78a5636f43172f60,
	0x84c87814a1f0ab72, 0x8cc702081a6439ec,
	0x90befffa23631e28, 0xa4506cebde82bde9,
	0xbef9a3f7b2c67915, 0xc67178f2e372532b,
	0xca273eceea26619c, 0xd186b8c721c0c207,
	0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178,
	0x06f067aa72176fba, 0x0a637dc5a2c898a6,
	0x113f9804bef90dae, 0x1b710b35131c471b,
	0x28db77f523047d84, 0x32caab7b40c72493,
	0x3c9ebe0a15c9bebc, 0x431d67c49c100d4c,
	0x4cc5d4becb3e42b6, 0x597f299cfc657e2a,
	0x5fcb6fab3ad6faec, 0x6c44198c4a475817,
};

#define CH(x, y, z)	((x & y) ^ (~x & z))
#define MAJ(x, y, z)	((x & y) ^ (x & z) ^ (y & z))
#define BSIG0(x)	(rotr64(x, 28) ^ rotr64(x, 34) ^ rotr64(x, 39))
#define BSIG1(x)	(rotr64(x, 14) ^ rotr64(x, 18) ^ rotr64(x, 41))
#define SSIG0(x)	(rotr64(x, 1) ^ rotr64(x, 8) ^ (x >> 7))
#define SSIG1(x)	(rotr64(x, 19) ^ rotr64(x, 61) ^ (x >> 6))

void
sha512_block(struct sha512_state *state)
{
	uint64_t	m[SHA512_BLOCKLEN_WORDS], W[SHA512_ROUNDS];
	uint64_t	a, b, c, d, e, f, g, h, T1, T2;
	size_t		i;

	for (i = 0; i < SHA512_BLOCKLEN_WORDS; i++)
		W[i] = m[i] = load64be(&state->b[i * 8]);
	for (; i < SHA512_ROUNDS; i++)
		W[i] = SSIG1(W[i - 2]) + W[i - 7] + SSIG0(W[i - 15]) +
		    W[i - 16];

	a = state->h0;
	b = state->h1;
	c = state->h2;
	d = state->h3;
	e = state->h4;
	f = state->h5;
	g = state->h6;
	h = state->h7;

	for (i = 0; i < SHA512_ROUNDS; i++) {
		T1 = h + BSIG1(e) + CH(e, f, g) + K[i] + W[i];
		T2 = BSIG0(a) + MAJ(a, b, c);
		h = g;
		g = f;
		f = e;
		e = d + T1;
		d = c;
		c = b;
		b = a;
		a = T1 + T2;
	}

	state->h0 += a;
	state->h1 += b;
	state->h2 += c;
	state->h3 += d;
	state->h4 += e;
	state->h5 += f;
	state->h6 += g;
	state->h7 += h;
}