core: use global algorithm structure instead of opt_nfactor.

Also squashed:

config: add log messages to set_algo() and set_nfactor().

algorithm: use set_algorithm_nfactor() when setting default nfactor in set_algorithm().

Otherwise algorithm->n defaults to 0.

P.S. Did I already mention how this could have been C++?..

algorithm.c

@@ -17,12 +17,17 @@ void set_algorithm(algorithm_t* algo, const char* newname) {
     algo->name[sizeof(algo->name) - 1] = '\0';
 
     if (strcmp(algo->name, "adaptive-nfactor") == 0) {
-	algo->nfactor = 11;
+	set_algorithm_nfactor(algo, 11);
     } else {
-	algo->nfactor = 10;
+	set_algorithm_nfactor(algo, 10);
     }
+
+    return;
 }
 
 void set_algorithm_nfactor(algorithm_t* algo, const uint8_t nfactor) {
     algo->nfactor = nfactor;
+    algo->n = (1 << nfactor);
+
+    return;
 }

algorithm.h

@@ -7,8 +7,9 @@
  * a specific coin.
  */
 typedef struct _algorithm_t {
-    char    name[20]; /* Human-readable identifier */
-    uint8_t nfactor;  /* N factor (CPU/Memory tradeoff parameter) */
+    char     name[20]; /* Human-readable identifier */
+    uint32_t n;        /* N (CPU/Memory tradeoff parameter) */
+    uint8_t  nfactor;  /* Factor of N above (n = 2^nfactor) */
 } algorithm_t;
 
 /* Set default parameters based on name. */

miner.h

@@ -3,6 +3,8 @@
 
 #include "config.h"
 
+#include "algorithm.h"
+
 #include <stdbool.h>
 #include <stdint.h>
 #include <sys/time.h>
@@ -1019,8 +1021,8 @@ extern int opt_queue;
 extern int opt_scantime;
 extern int opt_expiry;
 
-extern char* opt_algorithm;
-extern int opt_nfactor;
+extern char *opt_algorithm;
+extern algorithm_t *algorithm;
 
 extern cglock_t control_lock;
 extern pthread_mutex_t hash_lock;

ocl.c

@@ -33,6 +33,12 @@
 #include "findnonce.h"
 #include "ocl.h"
 
+/* FIXME: only here for global config vars, replace with configuration.h
+ * or similar as soon as config is in a struct instead of littered all
+ * over the global namespace.
+ */
+#include "miner.h"
+
 int opt_platform_id = -1;
 
 char *file_contents(const char *filename, int *length)
@@ -226,9 +232,6 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
 	cl_uint numDevices;
 	cl_int status;
 
-	/* Scrypt CPU/Memory cost parameter */
-	cl_uint N = (1 << opt_nfactor);
-
 	status = clGetPlatformIDs(0, NULL, &numPlatforms);
 	if (status != CL_SUCCESS) {
 		applog(LOG_ERR, "Error %d: Getting Platforms. (clGetPlatformsIDs)", status);
@@ -485,7 +488,7 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
 	if (!cgpu->opt_tc) {
 		unsigned int sixtyfours;
 
-		sixtyfours =  cgpu->max_alloc / 131072 / 64 / (N/1024) - 1;
+		sixtyfours =  cgpu->max_alloc / 131072 / 64 / (algorithm->n/1024) - 1;
 		cgpu->thread_concurrency = sixtyfours * 64;
 		if (cgpu->shaders && cgpu->thread_concurrency > cgpu->shaders) {
 			cgpu->thread_concurrency -= cgpu->thread_concurrency % cgpu->shaders;
@@ -525,7 +528,7 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
 	if (clState->goffset)
 		strcat(binaryfilename, "g");
 
-	sprintf(numbuf, "lg%utc%unf%u", cgpu->lookup_gap, (unsigned int)cgpu->thread_concurrency,opt_nfactor);
+	sprintf(numbuf, "lg%utc%unf%u", cgpu->lookup_gap, (unsigned int)cgpu->thread_concurrency, algorithm->nfactor);
 	strcat(binaryfilename, numbuf);
 
 	sprintf(numbuf, "w%d", (int)clState->wsize);
@@ -592,7 +595,7 @@ build:
 	char *CompilerOptions = (char *)calloc(1, 256);
 
 	sprintf(CompilerOptions, "-D LOOKUP_GAP=%d -D CONCURRENT_THREADS=%d -D WORKSIZE=%d -D NFACTOR=%d",
-			cgpu->lookup_gap, (unsigned int)cgpu->thread_concurrency, (int)clState->wsize, (unsigned int) opt_nfactor);
+			cgpu->lookup_gap, (unsigned int)cgpu->thread_concurrency, (int)clState->wsize, (unsigned int)algorithm->nfactor);
 
 	applog(LOG_DEBUG, "Setting worksize to %d", (int)(clState->wsize));
 	if (clState->vwidth > 1)
@@ -781,7 +784,8 @@ built:
 		return NULL;
 	}
 
-	size_t ipt = (N / cgpu->lookup_gap + (N % cgpu->lookup_gap > 0));
+	size_t ipt = (algorithm->n / cgpu->lookup_gap +
+		      (algorithm->n % cgpu->lookup_gap > 0));
 	size_t bufsize = 128 * ipt * cgpu->thread_concurrency;
 
 	/* Use the max alloc value which has been rounded to a power of

scrypt.c

@@ -353,10 +353,12 @@ salsa20_8(uint32_t B[16], const uint32_t Bx[16])
 	B[15] += x15;
 }
 
-/* cpu and memory intensive function to transform a 80 byte buffer into a 32 byte output
-   scratchpad size needs to be at least 63 + (128 * r * p) + (256 * r + 64) + (128 * r * N) bytes
+/* cpu and memory intensive function to transform a 80 byte buffer into
+ * a 32 byte output.
+ * scratchpad size needs to be at least (bytes):
+ * 63 + (128 * r * p) + (256 * r + 64) + (128 * r * N)
  */
-static void scrypt_n_1_1_256_sp(const uint32_t* input, char* scratchpad, uint32_t *ostate, const cl_uint n)
+static void scrypt_n_1_1_256_sp(const uint32_t* input, char* scratchpad, uint32_t *ostate)
 {
 	uint32_t * V;
 	uint32_t X[32];
@@ -370,7 +372,7 @@ static void scrypt_n_1_1_256_sp(const uint32_t* input, char* scratchpad, uint32_
 
 	PBKDF2_SHA256_80_128(input, X);
 
-	for (i = 0; i < n; i += 2) {
+	for (i = 0; i < algorithm->n; i += 2) {
 		memcpy(&V[i * 32], X, 128);
 
 		salsa20_8(&X[0], &X[16]);
@@ -381,8 +383,8 @@ static void scrypt_n_1_1_256_sp(const uint32_t* input, char* scratchpad, uint32_
 		salsa20_8(&X[0], &X[16]);
 		salsa20_8(&X[16], &X[0]);
 	}
-	for (i = 0; i < n; i += 2) {
-		j = X[16] & (n-1);
+	for (i = 0; i < algorithm->n; i += 2) {
+		j = X[16] & (algorithm->n-1);
 		p2 = (uint64_t *)(&V[j * 32]);
 		for(k = 0; k < 16; k++)
 			p1[k] ^= p2[k];
@@ -390,7 +392,7 @@ static void scrypt_n_1_1_256_sp(const uint32_t* input, char* scratchpad, uint32_
 		salsa20_8(&X[0], &X[16]);
 		salsa20_8(&X[16], &X[0]);
 
-		j = X[16] & (n-1);
+		j = X[16] & (algorithm->n-1);
 		p2 = (uint64_t *)(&V[j * 32]);
 		for(k = 0; k < 16; k++)
 			p1[k] ^= p2[k];
@@ -412,8 +414,8 @@ void scrypt_regenhash(struct work *work)
 	be32enc_vect(data, (const uint32_t *)work->data, 19);
 	data[19] = htobe32(*nonce);
 
-	scratchbuf = (char *)alloca((1 << opt_nfactor) * 128 + 512);
-	scrypt_n_1_1_256_sp(data, scratchbuf, ohash, (1 << opt_nfactor));
+	scratchbuf = (char *)alloca(algorithm->n * 128 + 512);
+	scrypt_n_1_1_256_sp(data, scratchbuf, ohash);
 	flip32(ohash, ohash);
 }
 
@@ -431,7 +433,7 @@ int scrypt_test(unsigned char *pdata, const unsigned char *ptarget, uint32_t non
 	be32enc_vect(data, (const uint32_t *)pdata, 19);
 	data[19] = htobe32(nonce);
 	scratchbuf = (char *)alloca(SCRATCHBUF_SIZE);
-	scrypt_n_1_1_256_sp(data, scratchbuf, ohash, (1 << opt_nfactor));
+	scrypt_n_1_1_256_sp(data, scratchbuf, ohash, algorithm->n);
 	tmp_hash7 = be32toh(ohash[7]);
 
 	applog(LOG_DEBUG, "htarget %08lx diff1 %08lx hash %08lx",
@@ -470,7 +472,7 @@ bool scanhash_scrypt(struct thr_info *thr, const unsigned char __maybe_unused *p
 
 		*nonce = ++n;
 		data[19] = htobe32(n);
-		scrypt_n_1_1_256_sp(data, scratchbuf, ostate, (1 << opt_nfactor));
+		scrypt_n_1_1_256_sp(data, scratchbuf, ostate, algorithm->n);
 		tmp_hash7 = be32toh(ostate[7]);
 
 		if (unlikely(tmp_hash7 <= Htarg)) {

sgminer.c

@@ -97,7 +97,6 @@ int opt_expiry = 28;
 
 char *opt_algorithm;
 algorithm_t *algorithm;
-int opt_nfactor = 10;
 
 static const bool opt_time = true;
 unsigned long long global_hashrate;
@@ -1014,6 +1013,7 @@ static void load_temp_cutoffs()
 static char *set_algo(const char *arg)
 {
 	set_algorithm(algorithm, arg);
+	applog(LOG_INFO, "Set algorithm to %s", algorithm->name);
 
 	return NULL;
 }
@@ -1021,6 +1021,9 @@ static char *set_algo(const char *arg)
 static char *set_nfactor(const char *arg)
 {
 	set_algorithm_nfactor(algorithm, (uint8_t)atoi(arg));
+	applog(LOG_INFO, "Set algorithm N-factor to %d (N to %d)",
+	       algorithm->nfactor, algorithm->n);
+
 	return NULL;
 }