Use cpu scrypt code to check if an scrypt share is below target before submitting it.

Makefile.am

@@ -45,6 +45,10 @@ cgminer_SOURCES += ocl.c ocl.h findnonce.c findnonce.h
 cgminer_SOURCES += adl.c adl.h adl_functions.h
 cgminer_SOURCES += *.cl
 
+if HAS_SCRYPT
+cgminer_SOURCES += scrypt.c
+endif
+
 if HAS_CPUMINE
 # original CPU related sources, unchanged
 cgminer_SOURCES	+= \
@@ -56,10 +60,6 @@ cgminer_SOURCES	+= \
 # the CPU portion extracted from original main.c
 cgminer_SOURCES += driver-cpu.h driver-cpu.c
 
-if HAS_SCRYPT
-cgminer_SOURCES += scrypt.c
-endif
-
 if HAS_YASM
 AM_CFLAGS	= -DHAS_YASM
 if HAVE_x86_64

cgminer.c

@@ -4012,7 +4012,7 @@ bool submit_nonce(struct thr_info *thr, struct work *work, uint32_t nonce)
 	/* Do one last check before attempting to submit the work */
 	/* Side effect: sets work->data for us */
 	if (!test_nonce(work, nonce)) {
-		applog(LOG_INFO, "Share below target");
+		applog(LOG_INFO, "Pool %d share below target", work->pool->pool_no);
 		return true;
 	}
 	return submit_work_sync(thr, work);

findnonce.c

@@ -220,6 +220,8 @@ static void send_nonce(struct pc_data *pcd, cl_uint nonce)
 	}
 }
 
+extern bool scrypt_scan_nonce(unsigned char *pdata, uint32_t nonce);
+
 static void *postcalc_hash(void *userdata)
 {
 	struct pc_data *pcd = (struct pc_data *)userdata;
@@ -234,9 +236,13 @@ static void *postcalc_hash(void *userdata)
 		if (nonce) {
 			applog(LOG_DEBUG, "OCL NONCE %u", nonce);
 #ifdef USE_SCRYPT
-			if (opt_scrypt)
-				submit_nonce(thr, pcd->work, nonce);
+			if (opt_scrypt) {
+				struct work *work = pcd->work;
+				if (scrypt_scan_nonce(work, nonce))
+					submit_nonce(thr, work, nonce);
 				else
+					applog(LOG_INFO, "Pool %d share below target", work->pool->pool_no);
+			} else
 #endif
 				send_nonce(pcd, nonce);
 		nonces++;

scrypt.c

@@ -407,6 +407,20 @@ static uint32_t scrypt_1024_1_1_256_sp(const uint32_t* input, char* scratchpad)
 	return PBKDF2_SHA256_80_128_32(input, X);
 }
 
+bool scrypt_scan_nonce(struct work *work, uint32_t nonce)
+{
+	uint32_t Htarg, tmp_hash7, data[20];
+	unsigned char *scratchbuf;
+
+	be32enc_vect(data, (const uint32_t *)work->data, 19);
+	data[19] = htobe32(nonce);
+
+	Htarg = ((const uint32_t *)work->target)[7];
+	scratchbuf = alloca(131584);
+	tmp_hash7 = scrypt_1024_1_1_256_sp(data, scratchbuf);
+	return (tmp_hash7 <= Htarg);
+}
+
 bool scanhash_scrypt(struct thr_info *thr, const unsigned char *pmidstate, unsigned char *pdata,
 	unsigned char *phash1, unsigned char *phash,
 	const unsigned char *ptarget,
@@ -423,7 +437,7 @@ bool scanhash_scrypt(struct thr_info *thr, const unsigned char *pmidstate, unsig
 
 	be32enc_vect(data, (const uint32_t *)pdata, 19);
 
-	scratchbuf = malloc(131583);
+	scratchbuf = malloc(131584);
 	if (unlikely(!scratchbuf)) {
 		applog(LOG_ERR, "Failed to malloc scratchbuf in scanhash_scrypt");
 		return ret;