Timersub is supported on all build platforms so do away with custom timerval_subtract function.

cgminer.c

@@ -3368,8 +3368,9 @@ static void hashmeter(int thr_id, struct timeval *diff,
 		if (want_per_device_stats) {
 			struct timeval now;
 			struct timeval elapsed;
+
 			gettimeofday(&now, NULL);
-			timeval_subtract(&elapsed, &now, &thr->cgpu->last_message_tv);
+			timersub(&now, &thr->cgpu->last_message_tv, &elapsed);
 			if (opt_log_interval <= elapsed.tv_sec) {
 				struct cgpu_info *cgpu = thr->cgpu;
 				char logline[255];
@@ -3389,7 +3390,7 @@ static void hashmeter(int thr_id, struct timeval *diff,
 	/* Totals are updated by all threads so can race without locking */
 	mutex_lock(&hash_lock);
 	gettimeofday(&temp_tv_end, NULL);
-	timeval_subtract(&total_diff, &temp_tv_end, &total_tv_end);
+	timersub(&temp_tv_end, &total_tv_end, &total_diff);
 
 	total_mhashes_done += local_mhashes;
 	local_mhashes_done += local_mhashes;
@@ -3403,7 +3404,7 @@ static void hashmeter(int thr_id, struct timeval *diff,
 	decay_time(&rolling, local_mhashes_done / local_secs);
 	global_hashrate = roundl(rolling) * 1000000;
 
-	timeval_subtract(&total_diff, &total_tv_end, &total_tv_start);
+	timersub(&total_tv_end, &total_tv_start, &total_diff);
 	total_secs = (double)total_diff.tv_sec +
 		((double)total_diff.tv_usec / 1000000.0);
 
@@ -3957,7 +3958,7 @@ void *miner_thread(void *userdata)
 	/* Try to cycle approximately 5 times before each log update */
 	const long cycle = opt_log_interval / 5 ? : 1;
 	struct timeval tv_start, tv_end, tv_workstart, tv_lastupdate;
-	struct timeval diff, sdiff, wdiff;
+	struct timeval diff, sdiff, wdiff = {0, 0};
 	uint32_t max_nonce = api->can_limit_work ? api->can_limit_work(mythr) : 0xffffffff;
 	unsigned long long hashes_done = 0;
 	unsigned long long hashes;
@@ -4074,7 +4075,7 @@ void *miner_thread(void *userdata)
 				cgpu->max_hashes = hashes;
 
 			gettimeofday(&tv_end, NULL);
-			timeval_subtract(&diff, &tv_end, &tv_start);
+			timersub(&tv_end, &tv_start, &diff);
 			sdiff.tv_sec += diff.tv_sec;
 			sdiff.tv_usec += diff.tv_usec;
 			if (sdiff.tv_usec > 1000000) {
@@ -4082,7 +4083,7 @@ void *miner_thread(void *userdata)
 				sdiff.tv_usec -= 1000000;
 			}
 
-			timeval_subtract(&wdiff, &tv_end, &tv_workstart);
+			timersub(&tv_end, &tv_workstart, &wdiff);
 			if (!requested) {
 				if (wdiff.tv_sec > request_interval || work->blk.nonce > request_nonce) {
 					thread_reportout(mythr);
@@ -4118,7 +4119,7 @@ void *miner_thread(void *userdata)
 				max_nonce = max_nonce * 0x400 / (((cycle * 1000000) + sdiff.tv_usec) / (cycle * 1000000 / 0x400));
 			}
 
-			timeval_subtract(&diff, &tv_end, &tv_lastupdate);
+			timersub(&tv_end, &tv_lastupdate, &diff);
 			if (diff.tv_sec >= opt_log_interval) {
 				hashmeter(thr_id, &diff, hashes_done);
 				hashes_done = 0;
@@ -4588,7 +4589,7 @@ static void print_summary(void)
 	int hours, mins, secs, i;
 	double utility, efficiency = 0.0;
 
-	timeval_subtract(&diff, &total_tv_end, &total_tv_start);
+	timersub(&total_tv_end, &total_tv_start, &diff);
 	hours = diff.tv_sec / 3600;
 	mins = (diff.tv_sec % 3600) / 60;
 	secs = diff.tv_sec % 60;

driver-modminer.c

@@ -466,7 +466,7 @@ modminer_process_results(struct thr_info*thr)
 
 	struct timeval tv_workend, elapsed;
 	gettimeofday(&tv_workend, NULL);
-	timeval_subtract(&elapsed, &tv_workend, &state->tv_workstart);
+	timersub(&tv_workend, &state->tv_workstart, &elapsed);
 
 	uint64_t hashes = (uint64_t)state->clock * (((uint64_t)elapsed.tv_sec * 1000000) + elapsed.tv_usec);
 	if (hashes > 0xffffffff)

miner.h

@@ -550,9 +550,6 @@ typedef bool (*sha256_func)(int thr_id, const unsigned char *pmidstate,
 	uint32_t *last_nonce,
 	uint32_t nonce);
 
-extern int
-timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y);
-
 extern bool fulltest(const unsigned char *hash, const unsigned char *target);
 
 extern int opt_scantime;

util.c

@@ -491,35 +491,6 @@ bool hex2bin(unsigned char *p, const char *hexstr, size_t len)
 	return (len == 0 && *hexstr == 0) ? true : false;
 }
 
-/* Subtract the `struct timeval' values X and Y,
-   storing the result in RESULT.
-   Return 1 if the difference is negative, otherwise 0.  */
-
-int timeval_subtract(struct timeval *result, struct timeval *x, struct timeval *y)
-{
-	/* Perform the carry for the later subtraction by updating Y. */
-	if (x->tv_usec < y->tv_usec) {
-		int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
-
-		y->tv_usec -= 1000000 * nsec;
-		y->tv_sec += nsec;
-	}
-	if (x->tv_usec - y->tv_usec > 1000000) {
-		int nsec = (x->tv_usec - y->tv_usec) / 1000000;
-
-		y->tv_usec += 1000000 * nsec;
-		y->tv_sec -= nsec;
-	}
-
-	/* Compute the time remaining to wait.
-	 * `tv_usec' is certainly positive. */
-	result->tv_sec = x->tv_sec - y->tv_sec;
-	result->tv_usec = x->tv_usec - y->tv_usec;
-
-	/* Return 1 if result is negative. */
-	return x->tv_sec < y->tv_sec;
-}
-
 bool fulltest(const unsigned char *hash, const unsigned char *target)
 {
 	unsigned char hash_swap[32], target_swap[32];