Fixed problem with stratum support when mining FC, GRS and TWE. Added --difficulty-multiplier parameter for controlling stratum difficulty multiplier.

sgminer.c

@@ -150,6 +150,7 @@ int opt_tcp_keepalive = 30;
 #else
 int opt_tcp_keepalive;
 #endif
+double opt_diff_mult = 1.0;
 
 char *opt_kernel_path;
 char *sgminer_path;
@@ -1055,6 +1056,18 @@ static char *set_null(const char __maybe_unused *arg)
 	return NULL;
 }
 
+char *set_difficulty_multiplier(char *arg)
+{
+	char **endptr = NULL;
+	if (!(arg && arg[0]))
+		return "Invalid parameters for set difficulty multiplier";
+	opt_diff_mult = strtod(arg, endptr);
+	if (opt_diff_mult == 0 || endptr == arg)
+		return "Invalid value passed to set difficulty multiplier";
+
+	return NULL;
+}
+
 /* These options are available from config file or commandline */
 static struct opt_table opt_config_table[] = {
 	OPT_WITH_ARG("--api-allow",
@@ -1354,6 +1367,9 @@ static struct opt_table opt_config_table[] = {
 			"Display extra work time debug information"),
 	OPT_WITH_ARG("--pools",
 			opt_set_bool, NULL, NULL, opt_hidden),
+	OPT_WITH_ARG("--difficulty-multiplier",
+			set_difficulty_multiplier, NULL, NULL, 
+			"Difficulty multiplier for jobs received from stratum pools"),
 	OPT_ENDTABLE
 };
 
@@ -5908,7 +5924,10 @@ static void gen_stratum_work(struct pool *pool, struct work *work)
 	cg_dwlock(&pool->data_lock);
 
 	/* Generate merkle root */
-	gen_hash(pool->coinbase, merkle_root, pool->swork.cb_len);
+	if (gpus[0].kernel == KL_FUGUECOIN || gpus[0].kernel == KL_GROESTLCOIN || gpus[0].kernel == KL_TWECOIN)
+		sha256(pool->coinbase, pool->swork.cb_len, merkle_root);
+	else
+		gen_hash(pool->coinbase, merkle_root, pool->swork.cb_len);
 	memcpy(merkle_sha, merkle_root, 32);
 	for (i = 0; i < pool->swork.merkles; i++) {
 		memcpy(merkle_sha + 32, pool->swork.merkle_bin[i], 32);

util.c

@@ -45,8 +45,7 @@
 #include "util.h"
 
 #define DEFAULT_SOCKWAIT 60
-#define DM_SELECT(x, y, z) (dm_mode == DM_BITCOIN ? x : (dm_mode == DM_QUARKCOIN ? y : z))
+extern double opt_diff_mult;
-extern enum diff_calc_mode dm_mode;
 
 bool successful_connect = false;
 static void keep_sockalive(SOCKETTYPE fd)
@@ -1644,7 +1643,7 @@ static bool parse_diff(struct pool *pool, json_t *val)
 {
 	double old_diff, diff;
 
-	diff = json_number_value(json_array_get(val, 0)) * DM_SELECT(1, 256, 1);
+	diff = json_number_value(json_array_get(val, 0)) * opt_diff_mult;
 	if (diff == 0)
 		return false;