/*
 * Copyright 2011 ArtForz, 2011-2012 pooler
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.  See COPYING for more details.
 */

#include "cpuminer-config.h"
#include "miner.h"

#include <string.h>
#include <stdint.h>

static const uint32_t sha256_h[8] = {
	0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
	0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
};

static const uint32_t sha256_k[64] = {
	0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
	0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
	0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
	0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
	0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
	0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
	0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
	0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
	0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
	0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
	0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
	0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
	0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
	0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
	0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
	0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};

void sha256_init(uint32_t *state)
{
	memcpy(state, sha256_h, 32);
}

/* Elementary functions used by SHA256 */
#define Ch(x, y, z)     ((x & (y ^ z)) ^ z)
#define Maj(x, y, z)    ((x & (y | z)) | (y & z))
#define ROTR(x, n)      ((x >> n) | (x << (32 - n)))
#define S0(x)           (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define S1(x)           (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
#define s0(x)           (ROTR(x, 7) ^ ROTR(x, 18) ^ (x >> 3))
#define s1(x)           (ROTR(x, 17) ^ ROTR(x, 19) ^ (x >> 10))

/* SHA256 round function */
#define RND(a, b, c, d, e, f, g, h, k) \
	do { \
		t0 = h + S1(e) + Ch(e, f, g) + k; \
		t1 = S0(a) + Maj(a, b, c); \
		d += t0; \
		h  = t0 + t1; \
	} while (0)

/* Adjusted round function for rotating state */
#define RNDr(S, W, i) \
	RND(S[(64 - i) % 8], S[(65 - i) % 8], \
	    S[(66 - i) % 8], S[(67 - i) % 8], \
	    S[(68 - i) % 8], S[(69 - i) % 8], \
	    S[(70 - i) % 8], S[(71 - i) % 8], \
	    W[i] + sha256_k[i])

/*
 * SHA256 block compression function.  The 256-bit state is transformed via
 * the 512-bit input block to produce a new state.
 */
void sha256_transform(uint32_t *state, const uint32_t *block, int swap)
{
	uint32_t W[64];
	uint32_t S[8];
	uint32_t t0, t1;
	int i;

	/* 1. Prepare message schedule W. */
	if (swap) {
		for (i = 0; i < 16; i++)
			W[i] = swab32(block[i]);
	} else
		memcpy(W, block, 64);
	for (i = 16; i < 64; i += 2) {
		W[i]   = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16];
		W[i+1] = s1(W[i - 1]) + W[i - 6] + s0(W[i - 14]) + W[i - 15];
	}

	/* 2. Initialize working variables. */
	memcpy(S, state, 32);

	/* 3. Mix. */
	RNDr(S, W,  0);
	RNDr(S, W,  1);
	RNDr(S, W,  2);
	RNDr(S, W,  3);
	RNDr(S, W,  4);
	RNDr(S, W,  5);
	RNDr(S, W,  6);
	RNDr(S, W,  7);
	RNDr(S, W,  8);
	RNDr(S, W,  9);
	RNDr(S, W, 10);
	RNDr(S, W, 11);
	RNDr(S, W, 12);
	RNDr(S, W, 13);
	RNDr(S, W, 14);
	RNDr(S, W, 15);
	RNDr(S, W, 16);
	RNDr(S, W, 17);
	RNDr(S, W, 18);
	RNDr(S, W, 19);
	RNDr(S, W, 20);
	RNDr(S, W, 21);
	RNDr(S, W, 22);
	RNDr(S, W, 23);
	RNDr(S, W, 24);
	RNDr(S, W, 25);
	RNDr(S, W, 26);
	RNDr(S, W, 27);
	RNDr(S, W, 28);
	RNDr(S, W, 29);
	RNDr(S, W, 30);
	RNDr(S, W, 31);
	RNDr(S, W, 32);
	RNDr(S, W, 33);
	RNDr(S, W, 34);
	RNDr(S, W, 35);
	RNDr(S, W, 36);
	RNDr(S, W, 37);
	RNDr(S, W, 38);
	RNDr(S, W, 39);
	RNDr(S, W, 40);
	RNDr(S, W, 41);
	RNDr(S, W, 42);
	RNDr(S, W, 43);
	RNDr(S, W, 44);
	RNDr(S, W, 45);
	RNDr(S, W, 46);
	RNDr(S, W, 47);
	RNDr(S, W, 48);
	RNDr(S, W, 49);
	RNDr(S, W, 50);
	RNDr(S, W, 51);
	RNDr(S, W, 52);
	RNDr(S, W, 53);
	RNDr(S, W, 54);
	RNDr(S, W, 55);
	RNDr(S, W, 56);
	RNDr(S, W, 57);
	RNDr(S, W, 58);
	RNDr(S, W, 59);
	RNDr(S, W, 60);
	RNDr(S, W, 61);
	RNDr(S, W, 62);
	RNDr(S, W, 63);

	/* 4. Mix local working variables into global state */
	for (i = 0; i < 8; i++)
		state[i] += S[i];
}

#if defined(__x86_64__)

#define SHA256D_WAYS 4

void sha256d_4way(uint32_t *hash,  uint32_t *data, const uint32_t *midstate);

#else

#define SHA256D_WAYS 1

static const uint32_t sha256d_hash1[16] = {
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x80000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000100
};

static inline void sha256d(uint32_t *hash, uint32_t *W,
	const uint32_t *midstate)
{
	uint32_t S[64];
	uint32_t t0, t1;
	int i;

	for (i = 16; i < 64; i += 2) {
		W[i]   = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16];
		W[i+1] = s1(W[i - 1]) + W[i - 6] + s0(W[i - 14]) + W[i - 15];
	}

	memcpy(S, midstate, 32);

	RNDr(S, W,  0);
	RNDr(S, W,  1);
	RNDr(S, W,  2);
	RNDr(S, W,  3);
	RNDr(S, W,  4);
	RNDr(S, W,  5);
	RNDr(S, W,  6);
	RNDr(S, W,  7);
	RNDr(S, W,  8);
	RNDr(S, W,  9);
	RNDr(S, W, 10);
	RNDr(S, W, 11);
	RNDr(S, W, 12);
	RNDr(S, W, 13);
	RNDr(S, W, 14);
	RNDr(S, W, 15);
	RNDr(S, W, 16);
	RNDr(S, W, 17);
	RNDr(S, W, 18);
	RNDr(S, W, 19);
	RNDr(S, W, 20);
	RNDr(S, W, 21);
	RNDr(S, W, 22);
	RNDr(S, W, 23);
	RNDr(S, W, 24);
	RNDr(S, W, 25);
	RNDr(S, W, 26);
	RNDr(S, W, 27);
	RNDr(S, W, 28);
	RNDr(S, W, 29);
	RNDr(S, W, 30);
	RNDr(S, W, 31);
	RNDr(S, W, 32);
	RNDr(S, W, 33);
	RNDr(S, W, 34);
	RNDr(S, W, 35);
	RNDr(S, W, 36);
	RNDr(S, W, 37);
	RNDr(S, W, 38);
	RNDr(S, W, 39);
	RNDr(S, W, 40);
	RNDr(S, W, 41);
	RNDr(S, W, 42);
	RNDr(S, W, 43);
	RNDr(S, W, 44);
	RNDr(S, W, 45);
	RNDr(S, W, 46);
	RNDr(S, W, 47);
	RNDr(S, W, 48);
	RNDr(S, W, 49);
	RNDr(S, W, 50);
	RNDr(S, W, 51);
	RNDr(S, W, 52);
	RNDr(S, W, 53);
	RNDr(S, W, 54);
	RNDr(S, W, 55);
	RNDr(S, W, 56);
	RNDr(S, W, 57);
	RNDr(S, W, 58);
	RNDr(S, W, 59);
	RNDr(S, W, 60);
	RNDr(S, W, 61);
	RNDr(S, W, 62);
	RNDr(S, W, 63);

	for (i = 0; i < 8; i++)
		S[i] += midstate[i];
	
	memcpy(S + 8, sha256d_hash1 + 8, 32);
	for (i = 16; i < 64; i += 2) {
		S[i]   = s1(S[i - 2]) + S[i - 7] + s0(S[i - 15]) + S[i - 16];
		S[i+1] = s1(S[i - 1]) + S[i - 6] + s0(S[i - 14]) + S[i - 15];
	}

	sha256_init(hash);

	RNDr(hash, S,  0);
	RNDr(hash, S,  1);
	RNDr(hash, S,  2);
	RNDr(hash, S,  3);
	RNDr(hash, S,  4);
	RNDr(hash, S,  5);
	RNDr(hash, S,  6);
	RNDr(hash, S,  7);
	RNDr(hash, S,  8);
	RNDr(hash, S,  9);
	RNDr(hash, S, 10);
	RNDr(hash, S, 11);
	RNDr(hash, S, 12);
	RNDr(hash, S, 13);
	RNDr(hash, S, 14);
	RNDr(hash, S, 15);
	RNDr(hash, S, 16);
	RNDr(hash, S, 17);
	RNDr(hash, S, 18);
	RNDr(hash, S, 19);
	RNDr(hash, S, 20);
	RNDr(hash, S, 21);
	RNDr(hash, S, 22);
	RNDr(hash, S, 23);
	RNDr(hash, S, 24);
	RNDr(hash, S, 25);
	RNDr(hash, S, 26);
	RNDr(hash, S, 27);
	RNDr(hash, S, 28);
	RNDr(hash, S, 29);
	RNDr(hash, S, 30);
	RNDr(hash, S, 31);
	RNDr(hash, S, 32);
	RNDr(hash, S, 33);
	RNDr(hash, S, 34);
	RNDr(hash, S, 35);
	RNDr(hash, S, 36);
	RNDr(hash, S, 37);
	RNDr(hash, S, 38);
	RNDr(hash, S, 39);
	RNDr(hash, S, 40);
	RNDr(hash, S, 41);
	RNDr(hash, S, 42);
	RNDr(hash, S, 43);
	RNDr(hash, S, 44);
	RNDr(hash, S, 45);
	RNDr(hash, S, 46);
	RNDr(hash, S, 47);
	RNDr(hash, S, 48);
	RNDr(hash, S, 49);
	RNDr(hash, S, 50);
	RNDr(hash, S, 51);
	RNDr(hash, S, 52);
	RNDr(hash, S, 53);
	RNDr(hash, S, 54);
	RNDr(hash, S, 55);
	RNDr(hash, S, 56);
	RNDr(hash, S, 57);
	RNDr(hash, S, 58);
	RNDr(hash, S, 59);
	RNDr(hash, S, 60);
	RNDr(hash, S, 61);
	RNDr(hash, S, 62);
	RNDr(hash, S, 63);

	for (i = 0; i < 8; i++)
		hash[i] += sha256_h[i];
}

#endif

int scanhash_sha256d(int thr_id, uint32_t *pdata, const uint32_t *ptarget,
	uint32_t max_nonce, unsigned long *hashes_done)
{
	uint32_t data[SHA256D_WAYS * 64] __attribute__((aligned(128)));
	uint32_t hash[SHA256D_WAYS * 8] __attribute__((aligned(32)));
	uint32_t midstate[SHA256D_WAYS * 8] __attribute__((aligned(32)));
	uint32_t tmp[8];
	uint32_t n = pdata[19] - 1;
	const uint32_t Htarg = ptarget[7];
	int i, j;
	
	for (i = 15; i >= 0; i--)
		for (j = 0; j < SHA256D_WAYS; j++)
			data[i * SHA256D_WAYS + j] = pdata[16 + i];
	
	sha256_init(midstate);
	sha256_transform(midstate, pdata, 0);
	for (i = 7; i >= 0; i--)
		for (j = 0; j < SHA256D_WAYS; j++)
			midstate[i * SHA256D_WAYS + j] = midstate[i];
	
	do {
		for (i = 0; i < SHA256D_WAYS; i++)
			data[SHA256D_WAYS * 3 + i] = ++n;
		
#if SHA256D_WAYS == 4
		sha256d_4way(hash, data, midstate);
#else
		sha256d(hash, data, midstate);
#endif
		
		for (i = 0; i < SHA256D_WAYS; i++) {
			if (hash[SHA256D_WAYS * 7 + i] <= Htarg) {
				for (j = 0; j < 8; j++)
					tmp[j] = hash[SHA256D_WAYS * j + i];
				if (fulltest(tmp, ptarget)) {
					*hashes_done = n - pdata[19] + 1;
					pdata[19] = data[SHA256D_WAYS * 3 + i];
					return 1;
				}
			}
		}
	} while (n < max_nonce && !work_restart[thr_id].restart);
	
	*hashes_done = n - pdata[19] + 1;
	pdata[19] = n;
	return 0;
}