use gostd for merkle in case of stratum

cpu-miner.c

@@ -654,11 +654,22 @@ static void stratum_gen_work(struct stratum_ctx *sctx, struct work *work)
 	memcpy(work->xnonce2, sctx->job.xnonce2, sctx->xnonce2_size);
 
 	/* Generate merkle root */
-	sha256d(merkle_root, sctx->job.coinbase, sctx->job.coinbase_size);
-	for (i = 0; i < sctx->job.merkle_count; i++) {
-		memcpy(merkle_root + 32, sctx->job.merkle[i], 32);
-		sha256d(merkle_root, merkle_root, 64);
-	}
+    if (opt_algo == ALGO_GOSTD)
+    {
+        gostd(merkle_root, sctx->job.coinbase, sctx->job.coinbase_size);
+	    for (i = 0; i < sctx->job.merkle_count; i++) {
+		    memcpy(merkle_root + 32, merkle_root, 32);
+		    gostd(merkle_root, merkle_root, 64);
+	    }
+    }
+    else
+    {
+	    sha256d(merkle_root, sctx->job.coinbase, sctx->job.coinbase_size);
+	    for (i = 0; i < sctx->job.merkle_count; i++) {
+		    memcpy(merkle_root + 32, sctx->job.merkle[i], 32);
+		    sha256d(merkle_root, merkle_root, 64);
+	    }
+    }
 
 	/* Increment extranonce2 */
 	for (i = 0; i < sctx->xnonce2_size && !++sctx->job.xnonce2[i]; i++);

gost.c

@@ -1223,6 +1223,16 @@ void sph_gostd(void *cc, const void *data, size_t len)
 	hash_256(digest, 64, cc);
 }
 
+void gostd(void *output, const void *input, size_t len)
+{
+	unsigned char hash[64];
+
+	sph_gost512(hash, (const void*)input, len);
+	sph_gost256(hash, (const void*)hash, 64);
+
+	memcpy(output, hash, 32);
+}
+
 int scanhash_gostd(int thr_id, uint32_t *pdata, const uint32_t *ptarget,
 	uint32_t max_nonce, unsigned long *hashes_done)
 {

miner.h

@@ -134,6 +134,8 @@ void sha256_init(uint32_t *state);
 void sha256_transform(uint32_t *state, const uint32_t *block, int swap);
 void sha256d(unsigned char *hash, const unsigned char *data, int len);
 
+void gostd(void *output, const void *input, size_t len);
+
 #if defined(__ARM_NEON__) || defined(__i386__) || defined(__x86_64__)
 #define HAVE_SHA256_4WAY 1
 int sha256_use_4way();