cpuminer/scrypt.c

/*
 * Copyright 2009 Colin Percival, 2011 ArtForz, 2011-2012 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 "cpuminer-config.h"
#include "miner.h"

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

static const uint32_t keypad[12] = {
	0x80000000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00000280
};
static const uint32_t innerpad[11] = {
	0x80000000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x000004a0
};
static const uint32_t outerpad[8] = {
	0x80000000, 0, 0, 0, 0, 0, 0, 0x00000300
};
static const uint32_t finalblk[16] = {
	0x00000001, 0x80000000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00000620
};

static inline void HMAC_SHA256_80_init(const uint32_t *key,
	uint32_t *tstate, uint32_t *ostate)
{
	uint32_t ihash[8];
	uint32_t pad[16];
	int i;

	/* tstate is assumed to contain the midstate of key */
	memcpy(pad, key + 16, 16);
	memcpy(pad + 4, keypad, 48);
	sha256_transform(tstate, pad, 0);
	memcpy(ihash, tstate, 32);

	sha256_init(ostate);
	for (i = 0; i < 8; i++)
		pad[i] = ihash[i] ^ 0x5c5c5c5c;
	for (; i < 16; i++)
		pad[i] = 0x5c5c5c5c;
	sha256_transform(ostate, pad, 0);

	sha256_init(tstate);
	for (i = 0; i < 8; i++)
		pad[i] = ihash[i] ^ 0x36363636;
	for (; i < 16; i++)
		pad[i] = 0x36363636;
	sha256_transform(tstate, pad, 0);
}

static inline void PBKDF2_SHA256_80_128(const uint32_t *tstate,
	const uint32_t *ostate, const uint32_t *salt, uint32_t *output)
{
	uint32_t istate[8], ostate2[8];
	uint32_t ibuf[16], obuf[16];
	int i, j;

	memcpy(istate, tstate, 32);
	sha256_transform(istate, salt, 0);
	
	memcpy(ibuf, salt + 16, 16);
	memcpy(ibuf + 5, innerpad, 44);
	memcpy(obuf + 8, outerpad, 32);

	for (i = 0; i < 4; i++) {
		memcpy(obuf, istate, 32);
		ibuf[4] = i + 1;
		sha256_transform(obuf, ibuf, 0);

		memcpy(ostate2, ostate, 32);
		sha256_transform(ostate2, obuf, 0);
		for (j = 0; j < 8; j++)
			output[8 * i + j] = swab32(ostate2[j]);
	}
}

static inline void PBKDF2_SHA256_128_32(uint32_t *tstate, uint32_t *ostate,
	const uint32_t *salt, uint32_t *output)
{
	uint32_t buf[16];
	int i;
	
	sha256_transform(tstate, salt, 1);
	sha256_transform(tstate, salt + 16, 1);
	sha256_transform(tstate, finalblk, 0);
	memcpy(buf, tstate, 32);
	memcpy(buf + 8, outerpad, 32);

	sha256_transform(ostate, buf, 0);
	for (i = 0; i < 8; i++)
		output[i] = swab32(ostate[i]);
}


#ifdef HAVE_SHA256_4WAY

static const uint32_t keypad_4way[4 * 12] = {
	0x80000000, 0x80000000, 0x80000000, 0x80000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000280, 0x00000280, 0x00000280, 0x00000280
};
static const uint32_t innerpad_4way[4 * 11] = {
	0x80000000, 0x80000000, 0x80000000, 0x80000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x000004a0, 0x000004a0, 0x000004a0, 0x000004a0
};
static const uint32_t outerpad_4way[4 * 8] = {
	0x80000000, 0x80000000, 0x80000000, 0x80000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000300, 0x00000300, 0x00000300, 0x00000300
};
static const uint32_t finalblk_4way[4 * 16] __attribute__((aligned(16))) = {
	0x00000001, 0x00000001, 0x00000001, 0x00000001,
	0x80000000, 0x80000000, 0x80000000, 0x80000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000000, 0x00000000, 0x00000000, 0x00000000,
	0x00000620, 0x00000620, 0x00000620, 0x00000620
};

static inline void HMAC_SHA256_80_init_4way(const uint32_t *key,
	uint32_t *tstate, uint32_t *ostate)
{
	uint32_t ihash[4 * 8] __attribute__((aligned(16)));
	uint32_t pad[4 * 16] __attribute__((aligned(16)));
	int i;

	/* tstate is assumed to contain the midstate of key */
	memcpy(pad, key + 4 * 16, 4 * 16);
	memcpy(pad + 4 * 4, keypad_4way, 4 * 48);
	sha256_transform_4way(tstate, pad, 0);
	memcpy(ihash, tstate, 4 * 32);

	sha256_init_4way(ostate);
	for (i = 0; i < 4 * 8; i++)
		pad[i] = ihash[i] ^ 0x5c5c5c5c;
	for (; i < 4 * 16; i++)
		pad[i] = 0x5c5c5c5c;
	sha256_transform_4way(ostate, pad, 0);

	sha256_init_4way(tstate);
	for (i = 0; i < 4 * 8; i++)
		pad[i] = ihash[i] ^ 0x36363636;
	for (; i < 4 * 16; i++)
		pad[i] = 0x36363636;
	sha256_transform_4way(tstate, pad, 0);
}

static inline void PBKDF2_SHA256_80_128_4way(const uint32_t *tstate,
	const uint32_t *ostate, const uint32_t *salt, uint32_t *output)
{
	uint32_t istate[4 * 8] __attribute__((aligned(16)));
	uint32_t ostate2[4 * 8] __attribute__((aligned(16)));
	uint32_t ibuf[4 * 16] __attribute__((aligned(16)));
	uint32_t obuf[4 * 16] __attribute__((aligned(16)));
	int i, j;

	memcpy(istate, tstate, 4 * 32);
	sha256_transform_4way(istate, salt, 0);
	
	memcpy(ibuf, salt + 4 * 16, 4 * 16);
	memcpy(ibuf + 4 * 5, innerpad_4way, 4 * 44);
	memcpy(obuf + 4 * 8, outerpad_4way, 4 * 32);

	for (i = 0; i < 4; i++) {
		memcpy(obuf, istate, 4 * 32);
		ibuf[4 * 4 + 0] = i + 1;
		ibuf[4 * 4 + 1] = i + 1;
		ibuf[4 * 4 + 2] = i + 1;
		ibuf[4 * 4 + 3] = i + 1;
		sha256_transform_4way(obuf, ibuf, 0);

		memcpy(ostate2, ostate, 4 * 32);
		sha256_transform_4way(ostate2, obuf, 0);
		for (j = 0; j < 4 * 8; j++)
			output[4 * 8 * i + j] = swab32(ostate2[j]);
	}
}

static inline void PBKDF2_SHA256_128_32_4way(uint32_t *tstate,
	uint32_t *ostate, const uint32_t *salt, uint32_t *output)
{
	uint32_t buf[4 * 16] __attribute__((aligned(16)));
	int i;
	
	sha256_transform_4way(tstate, salt, 1);
	sha256_transform_4way(tstate, salt + 4 * 16, 1);
	sha256_transform_4way(tstate, finalblk_4way, 0);
	memcpy(buf, tstate, 4 * 32);
	memcpy(buf + 4 * 8, outerpad_4way, 4 * 32);

	sha256_transform_4way(ostate, buf, 0);
	for (i = 0; i < 4 * 8; i++)
		output[i] = swab32(ostate[i]);
}

#endif /* HAVE_SHA256_4WAY */


#if defined(__x86_64__)

#define SCRYPT_MAX_WAYS 12
#define HAVE_SCRYPT_3WAY 1
int scrypt_best_throughput();
void scrypt_core(uint32_t *X, uint32_t *V);
void scrypt_core_3way(uint32_t *X, uint32_t *V);

#elif defined(__i386__)

#define SCRYPT_MAX_WAYS 4
#define scrypt_best_throughput() 1
void scrypt_core(uint32_t *X, uint32_t *V);

#else

static inline void xor_salsa8(uint32_t B[16], const uint32_t Bx[16])
{
	uint32_t x00,x01,x02,x03,x04,x05,x06,x07,x08,x09,x10,x11,x12,x13,x14,x15;
	int i;

	x00 = (B[ 0] ^= Bx[ 0]);
	x01 = (B[ 1] ^= Bx[ 1]);
	x02 = (B[ 2] ^= Bx[ 2]);
	x03 = (B[ 3] ^= Bx[ 3]);
	x04 = (B[ 4] ^= Bx[ 4]);
	x05 = (B[ 5] ^= Bx[ 5]);
	x06 = (B[ 6] ^= Bx[ 6]);
	x07 = (B[ 7] ^= Bx[ 7]);
	x08 = (B[ 8] ^= Bx[ 8]);
	x09 = (B[ 9] ^= Bx[ 9]);
	x10 = (B[10] ^= Bx[10]);
	x11 = (B[11] ^= Bx[11]);
	x12 = (B[12] ^= Bx[12]);
	x13 = (B[13] ^= Bx[13]);
	x14 = (B[14] ^= Bx[14]);
	x15 = (B[15] ^= Bx[15]);
	for (i = 0; i < 8; i += 2) {
#define R(a, b) (((a) << (b)) | ((a) >> (32 - (b))))
		/* Operate on columns. */
		x04 ^= R(x00+x12, 7);	x09 ^= R(x05+x01, 7);
		x14 ^= R(x10+x06, 7);	x03 ^= R(x15+x11, 7);
		
		x08 ^= R(x04+x00, 9);	x13 ^= R(x09+x05, 9);
		x02 ^= R(x14+x10, 9);	x07 ^= R(x03+x15, 9);
		
		x12 ^= R(x08+x04,13);	x01 ^= R(x13+x09,13);
		x06 ^= R(x02+x14,13);	x11 ^= R(x07+x03,13);
		
		x00 ^= R(x12+x08,18);	x05 ^= R(x01+x13,18);
		x10 ^= R(x06+x02,18);	x15 ^= R(x11+x07,18);
		
		/* Operate on rows. */
		x01 ^= R(x00+x03, 7);	x06 ^= R(x05+x04, 7);
		x11 ^= R(x10+x09, 7);	x12 ^= R(x15+x14, 7);
		
		x02 ^= R(x01+x00, 9);	x07 ^= R(x06+x05, 9);
		x08 ^= R(x11+x10, 9);	x13 ^= R(x12+x15, 9);
		
		x03 ^= R(x02+x01,13);	x04 ^= R(x07+x06,13);
		x09 ^= R(x08+x11,13);	x14 ^= R(x13+x12,13);
		
		x00 ^= R(x03+x02,18);	x05 ^= R(x04+x07,18);
		x10 ^= R(x09+x08,18);	x15 ^= R(x14+x13,18);
#undef R
	}
	B[ 0] += x00;
	B[ 1] += x01;
	B[ 2] += x02;
	B[ 3] += x03;
	B[ 4] += x04;
	B[ 5] += x05;
	B[ 6] += x06;
	B[ 7] += x07;
	B[ 8] += x08;
	B[ 9] += x09;
	B[10] += x10;
	B[11] += x11;
	B[12] += x12;
	B[13] += x13;
	B[14] += x14;
	B[15] += x15;
}

static inline void scrypt_core(uint32_t *X, uint32_t *V)
{
	uint32_t i, j, k;
	
	for (i = 0; i < 1024; i++) {
		memcpy(&V[i * 32], X, 128);
		xor_salsa8(&X[0], &X[16]);
		xor_salsa8(&X[16], &X[0]);
	}
	for (i = 0; i < 1024; i++) {
		j = 32 * (X[16] & 1023);
		for (k = 0; k < 32; k++)
			X[k] ^= V[j + k];
		xor_salsa8(&X[0], &X[16]);
		xor_salsa8(&X[16], &X[0]);
	}
}

#endif

#ifndef SCRYPT_MAX_WAYS
#define SCRYPT_MAX_WAYS 1
#define scrypt_best_throughput() 1
#endif

#define SCRYPT_BUFFER_SIZE (SCRYPT_MAX_WAYS * 131072 + 63)

unsigned char *scrypt_buffer_alloc()
{
	return malloc(SCRYPT_BUFFER_SIZE);
}

static void scrypt_1024_1_1_256(const uint32_t *input, uint32_t *output,
	uint32_t *midstate, unsigned char *scratchpad)
{
	uint32_t tstate[8], ostate[8];
	uint32_t X[32];
	uint32_t *V;
	
	V = (uint32_t *)(((uintptr_t)(scratchpad) + 63) & ~ (uintptr_t)(63));

	memcpy(tstate, midstate, 32);
	HMAC_SHA256_80_init(input, tstate, ostate);
	PBKDF2_SHA256_80_128(tstate, ostate, input, X);

	scrypt_core(X, V);

	PBKDF2_SHA256_128_32(tstate, ostate, X, output);
}

#ifdef HAVE_SHA256_4WAY
static void scrypt_1024_1_1_256_4way(const uint32_t *input,
	uint32_t *output, uint32_t *midstate, unsigned char *scratchpad)
{
	uint32_t tstate[4 * 8] __attribute__((aligned(128)));
	uint32_t ostate[4 * 8] __attribute__((aligned(128)));
	uint32_t W[4 * 32] __attribute__((aligned(128)));
	uint32_t X[4 * 32] __attribute__((aligned(128)));
	uint32_t *V;
	int i;
	
	V = (uint32_t *)(((uintptr_t)(scratchpad) + 63) & ~ (uintptr_t)(63));

	for (i = 0; i < 20; i++) {
		W[4 * i + 0] = input[0 * 20 + i];
		W[4 * i + 1] = input[1 * 20 + i];
		W[4 * i + 2] = input[2 * 20 + i];
		W[4 * i + 3] = input[3 * 20 + i];
	}
	for (i = 0; i < 8; i++) {
		tstate[4 * i + 0] = midstate[i];
		tstate[4 * i + 1] = midstate[i];
		tstate[4 * i + 2] = midstate[i];
		tstate[4 * i + 3] = midstate[i];
	}
	HMAC_SHA256_80_init_4way(W, tstate, ostate);
	PBKDF2_SHA256_80_128_4way(tstate, ostate, W, W);
	for (i = 0; i < 32; i++) {
		X[0 * 32 + i] = W[4 * i + 0];
		X[1 * 32 + i] = W[4 * i + 1];
		X[2 * 32 + i] = W[4 * i + 2];
		X[3 * 32 + i] = W[4 * i + 3];
	}
	scrypt_core(X + 0 * 32, V);
	scrypt_core(X + 1 * 32, V);
	scrypt_core(X + 2 * 32, V);
	scrypt_core(X + 3 * 32, V);
	for (i = 0; i < 32; i++) {
		W[4 * i + 0] = X[0 * 32 + i];
		W[4 * i + 1] = X[1 * 32 + i];
		W[4 * i + 2] = X[2 * 32 + i];
		W[4 * i + 3] = X[3 * 32 + i];
	}
	PBKDF2_SHA256_128_32_4way(tstate, ostate, W, W);
	for (i = 0; i < 8; i++) {
		output[0 * 8 + i] = W[4 * i + 0];
		output[1 * 8 + i] = W[4 * i + 1];
		output[2 * 8 + i] = W[4 * i + 2];
		output[3 * 8 + i] = W[4 * i + 3];
	}
}
#endif /* HAVE_SHA256_4WAY */

#ifdef HAVE_SCRYPT_3WAY
static void scrypt_1024_1_1_256_12way(const uint32_t *input,
	uint32_t *output, uint32_t *midstate, unsigned char *scratchpad)
{
	uint32_t tstate[12 * 8] __attribute__((aligned(128)));
	uint32_t ostate[12 * 8] __attribute__((aligned(128)));
	uint32_t W[12 * 32] __attribute__((aligned(128)));
	uint32_t X[12 * 32] __attribute__((aligned(128)));
	uint32_t *V;
	int i, j;
	
	V = (uint32_t *)(((uintptr_t)(scratchpad) + 63) & ~ (uintptr_t)(63));

	for (j = 0; j < 3; j++) {
		for (i = 0; i < 20; i++) {
			W[128 * j + 4 * i + 0] = input[80 * j + 0 * 20 + i];
			W[128 * j + 4 * i + 1] = input[80 * j + 1 * 20 + i];
			W[128 * j + 4 * i + 2] = input[80 * j + 2 * 20 + i];
			W[128 * j + 4 * i + 3] = input[80 * j + 3 * 20 + i];
		}
	}
	for (j = 0; j < 3; j++) {
		for (i = 0; i < 8; i++) {
			tstate[32 * j + 4 * i + 0] = midstate[i];
			tstate[32 * j + 4 * i + 1] = midstate[i];
			tstate[32 * j + 4 * i + 2] = midstate[i];
			tstate[32 * j + 4 * i + 3] = midstate[i];
		}
	}
	HMAC_SHA256_80_init_4way(W +   0, tstate +  0, ostate +  0);
	HMAC_SHA256_80_init_4way(W + 128, tstate + 32, ostate + 32);
	HMAC_SHA256_80_init_4way(W + 256, tstate + 64, ostate + 64);
	PBKDF2_SHA256_80_128_4way(tstate +  0, ostate +  0, W +   0, W +   0);
	PBKDF2_SHA256_80_128_4way(tstate + 32, ostate + 32, W + 128, W + 128);
	PBKDF2_SHA256_80_128_4way(tstate + 64, ostate + 64, W + 256, W + 256);
	for (j = 0; j < 3; j++) {
		for (i = 0; i < 32; i++) {
			X[128 * j + 0 * 32 + i] = W[128 * j + 4 * i + 0];
			X[128 * j + 1 * 32 + i] = W[128 * j + 4 * i + 1];
			X[128 * j + 2 * 32 + i] = W[128 * j + 4 * i + 2];
			X[128 * j + 3 * 32 + i] = W[128 * j + 4 * i + 3];
		}
	}
	scrypt_core_3way(X + 0 * 96, V);
	scrypt_core_3way(X + 1 * 96, V);
	scrypt_core_3way(X + 2 * 96, V);
	scrypt_core_3way(X + 3 * 96, V);
	for (j = 0; j < 3; j++) {
		for (i = 0; i < 32; i++) {
			W[128 * j + 4 * i + 0] = X[128 * j + 0 * 32 + i];
			W[128 * j + 4 * i + 1] = X[128 * j + 1 * 32 + i];
			W[128 * j + 4 * i + 2] = X[128 * j + 2 * 32 + i];
			W[128 * j + 4 * i + 3] = X[128 * j + 3 * 32 + i];
		}
	}
	PBKDF2_SHA256_128_32_4way(tstate +  0, ostate +  0, W +   0, W +   0);
	PBKDF2_SHA256_128_32_4way(tstate + 32, ostate + 32, W + 128, W + 128);
	PBKDF2_SHA256_128_32_4way(tstate + 64, ostate + 64, W + 256, W + 256);
	for (j = 0; j < 3; j++) {
		for (i = 0; i < 8; i++) {
			output[32 * j + 0 * 8 + i] = W[128 * j + 4 * i + 0];
			output[32 * j + 1 * 8 + i] = W[128 * j + 4 * i + 1];
			output[32 * j + 2 * 8 + i] = W[128 * j + 4 * i + 2];
			output[32 * j + 3 * 8 + i] = W[128 * j + 4 * i + 3];
		}
	}
}
#endif /* HAVE_SCRYPT_3WAY */

int scanhash_scrypt(int thr_id, uint32_t *pdata,
	unsigned char *scratchbuf, const uint32_t *ptarget,
	uint32_t max_nonce, unsigned long *hashes_done)
{
	uint32_t data[SCRYPT_MAX_WAYS * 20], hash[SCRYPT_MAX_WAYS * 8];
	uint32_t midstate[8];
	uint32_t n = pdata[19] - 1;
	const uint32_t Htarg = ptarget[7];
	int throughput = scrypt_best_throughput();
	int i;
	
#ifdef HAVE_SHA256_4WAY
	if (sha256_use_4way())
		throughput *= 4;
#endif
	
	for (i = 0; i < throughput; i++)
		memcpy(data + i * 20, pdata, 80);
	
	sha256_init(midstate);
	sha256_transform(midstate, data, 0);
	
	do {
		for (i = 0; i < throughput; i++)
			data[i * 20 + 19] = ++n;
		
#ifdef HAVE_SHA256_4WAY
		if (throughput == 4)
			scrypt_1024_1_1_256_4way(data, hash, midstate, scratchbuf);
		else
#endif
#ifdef HAVE_SCRYPT_3WAY
		if (throughput == 12)
			scrypt_1024_1_1_256_12way(data, hash, midstate, scratchbuf);
		else
#endif
		scrypt_1024_1_1_256(data, hash, midstate, scratchbuf);
		
		for (i = 0; i < throughput; i++) {
			if (hash[i * 8 + 7] <= Htarg && fulltest(hash + i * 8, ptarget)) {
				*hashes_done = n - pdata[19] + 1;
				pdata[19] = data[i * 20 + 19];
				return 1;
			}
		}
	} while (n < max_nonce && !work_restart[thr_id].restart);
	
	*hashes_done = n - pdata[19] + 1;
	pdata[19] = n;
	return 0;
}