/*
 * Copyright 2009 Colin Percival, 2011 ArtForz, 2012-2013 pooler
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file was originally written by Colin Percival as part of the Tarsnap
 * online backup system.
 */

#include "crypto/scrypt.h"
#include "support/experimental.h"
#include <stdlib.h>
#include <stdint.h>
#include <string.h>

#include <emmintrin.h>

// this entire functionality is experimental
EXPERIMENTAL_FEATURE

static inline void xor_salsa8_sse2(__m128i B[4], const __m128i Bx[4])
{
	__m128i X0, X1, X2, X3;
	__m128i T;
	int i;

	X0 = B[0] = _mm_xor_si128(B[0], Bx[0]);
	X1 = B[1] = _mm_xor_si128(B[1], Bx[1]);
	X2 = B[2] = _mm_xor_si128(B[2], Bx[2]);
	X3 = B[3] = _mm_xor_si128(B[3], Bx[3]);

	for (i = 0; i < 8; i += 2) {
		/* Operate on "columns". */
		T = _mm_add_epi32(X0, X3);
		X1 = _mm_xor_si128(X1, _mm_slli_epi32(T, 7));
		X1 = _mm_xor_si128(X1, _mm_srli_epi32(T, 25));
		T = _mm_add_epi32(X1, X0);
		X2 = _mm_xor_si128(X2, _mm_slli_epi32(T, 9));
		X2 = _mm_xor_si128(X2, _mm_srli_epi32(T, 23));
		T = _mm_add_epi32(X2, X1);
		X3 = _mm_xor_si128(X3, _mm_slli_epi32(T, 13));
		X3 = _mm_xor_si128(X3, _mm_srli_epi32(T, 19));
		T = _mm_add_epi32(X3, X2);
		X0 = _mm_xor_si128(X0, _mm_slli_epi32(T, 18));
		X0 = _mm_xor_si128(X0, _mm_srli_epi32(T, 14));

		/* Rearrange data. */
		X1 = _mm_shuffle_epi32(X1, 0x93);
		X2 = _mm_shuffle_epi32(X2, 0x4E);
		X3 = _mm_shuffle_epi32(X3, 0x39);

		/* Operate on "rows". */
		T = _mm_add_epi32(X0, X1);
		X3 = _mm_xor_si128(X3, _mm_slli_epi32(T, 7));
		X3 = _mm_xor_si128(X3, _mm_srli_epi32(T, 25));
		T = _mm_add_epi32(X3, X0);
		X2 = _mm_xor_si128(X2, _mm_slli_epi32(T, 9));
		X2 = _mm_xor_si128(X2, _mm_srli_epi32(T, 23));
		T = _mm_add_epi32(X2, X3);
		X1 = _mm_xor_si128(X1, _mm_slli_epi32(T, 13));
		X1 = _mm_xor_si128(X1, _mm_srli_epi32(T, 19));
		T = _mm_add_epi32(X1, X2);
		X0 = _mm_xor_si128(X0, _mm_slli_epi32(T, 18));
		X0 = _mm_xor_si128(X0, _mm_srli_epi32(T, 14));

		/* Rearrange data. */
		X1 = _mm_shuffle_epi32(X1, 0x39);
		X2 = _mm_shuffle_epi32(X2, 0x4E);
		X3 = _mm_shuffle_epi32(X3, 0x93);
	}

	B[0] = _mm_add_epi32(B[0], X0);
	B[1] = _mm_add_epi32(B[1], X1);
	B[2] = _mm_add_epi32(B[2], X2);
	B[3] = _mm_add_epi32(B[3], X3);
}

void scrypt_1024_1_1_256_sp_sse2(const char *input, char *output, char *scratchpad)
{
	uint8_t B[128];
	union {
		__m128i i128[8];
		uint32_t u32[32];
	} X;
	__m128i *V;
	uint32_t i, j, k;

	V = (__m128i *)(((uintptr_t)(scratchpad) + 63) & ~ (uintptr_t)(63));

	PBKDF2_SHA256((const uint8_t *)input, 80, (const uint8_t *)input, 80, 1, B, 128);

	for (k = 0; k < 2; k++) {
		for (i = 0; i < 16; i++) {
			X.u32[k * 16 + i] = le32dec(&B[(k * 16 + (i * 5 % 16)) * 4]);
		}
	}

	for (i = 0; i < 1024; i++) {
		for (k = 0; k < 8; k++)
			V[i * 8 + k] = X.i128[k];
		xor_salsa8_sse2(&X.i128[0], &X.i128[4]);
		xor_salsa8_sse2(&X.i128[4], &X.i128[0]);
	}
	for (i = 0; i < 1024; i++) {
		j = 8 * (X.u32[16] & 1023);
		for (k = 0; k < 8; k++)
			X.i128[k] = _mm_xor_si128(X.i128[k], V[j + k]);
		xor_salsa8_sse2(&X.i128[0], &X.i128[4]);
		xor_salsa8_sse2(&X.i128[4], &X.i128[0]);
	}

	for (k = 0; k < 2; k++) {
		for (i = 0; i < 16; i++) {
			le32enc(&B[(k * 16 + (i * 5 % 16)) * 4], X.u32[k * 16 + i]);
		}
	}

	PBKDF2_SHA256((const uint8_t *)input, 80, B, 128, 1, (uint8_t *)output, 32);
}
