diff --git a/src/command.c b/src/command.c
index 50dfadf5..6e3ce89e 100644
--- a/src/command.c
+++ b/src/command.c
@@ -441,88 +441,77 @@ static bool cmd_target_power(target *t, int argc, const char **argv)
 #endif
 
 #ifdef ENABLE_RTT
-const char* onoroffstr[2] = {"off", "on"};
-static const char* onoroff(bool bval) {
-	return bval ? onoroffstr[1] : onoroffstr[0];
+static const char *on_or_off(const bool value)
+{
+	return value ? "on" : "off";
 }
 
 static bool cmd_rtt(target *t, int argc, const char **argv)
 {
 	(void)t;
-	if ((argc == 1) || ((argc == 2) && !strncmp(argv[1], "enabled", strlen(argv[1])))) {
+	const size_t command_len = strlen(argv[1]);
+	if (argc == 1 || (argc == 2 && !strncmp(argv[1], "enabled", command_len))) {
 		rtt_enabled = true;
 		rtt_found = false;
-	}
-	else if ((argc == 2) && !strncmp(argv[1], "disabled", strlen(argv[1]))) {
+	} else if ((argc == 2) && !strncmp(argv[1], "disabled", command_len)) {
 		rtt_enabled = false;
 		rtt_found = false;
-	}
-	else if ((argc == 2) && !strncmp(argv[1], "status", strlen(argv[1]))) {
-		gdb_outf("rtt: %s found: %s ident: ",
-			onoroff(rtt_enabled), rtt_found ? "yes" : "no");
-		if (rtt_ident[0] == '\0')
-			gdb_out("off");
-		else
-			gdb_outf("\"%s\"", rtt_ident);
-		gdb_outf(" halt: %s", onoroff(target_no_background_memory_access(t)));
+	} else if ((argc == 2) && !strncmp(argv[1], "status", command_len)) {
+		gdb_outf("rtt: %s found: %s ident: \"%s\"", on_or_off(rtt_enabled), rtt_found ? "yes" : "no",
+			rtt_ident[0] == '\0' ? "off" : rtt_ident);
+		gdb_outf(" halt: %s", on_or_off(target_no_background_memory_access(t)));
 		gdb_out(" channels: ");
-		if (rtt_auto_channel) gdb_out("auto ");
-		for (uint32_t i = 0; i < MAX_RTT_CHAN; i++)
-			if (rtt_channel[i].is_enabled) gdb_outf("%d ", i);
-		gdb_outf("\nmax poll ms: %u min poll ms: %u max errs: %u\n",
-			rtt_max_poll_ms, rtt_min_poll_ms, rtt_max_poll_errs);
-	}
-	else if ((argc >= 2) && !strncmp(argv[1], "channel", strlen(argv[1]))) {
+		if (rtt_auto_channel)
+			gdb_out("auto ");
+		for (size_t i = 0; i < MAX_RTT_CHAN; i++) {
+			if (rtt_channel[i].is_enabled)
+				gdb_outf("%d ", i);
+		}
+		gdb_outf(
+			"\nmax poll ms: %u min poll ms: %u max errs: %u\n", rtt_max_poll_ms, rtt_min_poll_ms, rtt_max_poll_errs);
+	} else if (argc >= 2 && !strncmp(argv[1], "channel", command_len)) {
 		/* mon rtt channel switches to auto rtt channel selection
 		   mon rtt channel number... selects channels given */
-		for (uint32_t i = 0; i < MAX_RTT_CHAN; i++)
+		for (size_t i = 0; i < MAX_RTT_CHAN; i++)
 			rtt_channel[i].is_enabled = false;
-		if (argc == 2) {
+
+		if (argc == 2)
 			rtt_auto_channel = true;
-		} else {
+		else {
 			rtt_auto_channel = false;
-			for (int i = 2; i < argc; i++) {
-				int chan = atoi(argv[i]);
-				if ((chan >= 0) && (chan < MAX_RTT_CHAN))
-					rtt_channel[chan].is_enabled = true;
+			for (size_t i = 2; i < (size_t)argc; ++i) {
+				const uint32_t channel = strtoul(argv[i], NULL, 0);
+				if (channel < MAX_RTT_CHAN)
+					rtt_channel[channel].is_enabled = true;
 			}
 		}
-	}
-	else if ((argc == 2) && !strncmp(argv[1], "ident", strlen(argv[1]))) {
+	} else if (argc == 2 && !strncmp(argv[1], "ident", command_len))
 		rtt_ident[0] = '\0';
-	}
-	else if ((argc == 2) && !strncmp(argv[1], "poll", strlen(argv[1])))
+	else if (argc == 2 && !strncmp(argv[1], "poll", command_len))
 		gdb_outf("%u %u %u\n", rtt_max_poll_ms, rtt_min_poll_ms, rtt_max_poll_errs);
-	else if ((argc == 2) && !strncmp(argv[1], "cblock", strlen(argv[1]))) {
+	else if (argc == 2 && !strncmp(argv[1], "cblock", command_len)) {
 		gdb_outf("cbaddr: 0x%x\n", rtt_cbaddr);
 		gdb_out("ch ena cfg i/o buf@        size head@      tail@      flg\n");
-		for (uint32_t i = 0; i < MAX_RTT_CHAN; i++) {
-			gdb_outf("%2d   %c   %c %s 0x%08x %5d 0x%08x 0x%08x   %d\n",
-			i, rtt_channel[i].is_enabled ? 'y' : 'n', rtt_channel[i].is_configured ? 'y' : 'n',
-			rtt_channel[i].is_output ? "out" : "in ", rtt_channel[i].buf_addr, rtt_channel[i].buf_size,
-			rtt_channel[i].head_addr, rtt_channel[i].tail_addr, rtt_channel[i].flag);
+		for (size_t i = 0; i < MAX_RTT_CHAN; ++i) {
+			gdb_outf("%2zu   %c   %c %s 0x%08x %5d 0x%08x 0x%08x   %d\n", i, rtt_channel[i].is_enabled ? 'y' : 'n',
+				rtt_channel[i].is_configured ? 'y' : 'n', rtt_channel[i].is_output ? "out" : "in ",
+				rtt_channel[i].buf_addr, rtt_channel[i].buf_size, rtt_channel[i].head_addr, rtt_channel[i].tail_addr,
+				rtt_channel[i].flag);
 		}
-	}
-	else if ((argc == 3) && !strncmp(argv[1], "ident", strlen(argv[1]))) {
+	} else if (argc == 3 && !strncmp(argv[1], "ident", command_len)) {
 		strncpy(rtt_ident, argv[2], sizeof(rtt_ident));
-		rtt_ident[sizeof(rtt_ident)-1] = '\0';
-		for (uint32_t i = 0; i < sizeof(rtt_ident); i++)
-			if (rtt_ident[i] == '_') rtt_ident[i] = ' ';
-	}
-	else if ((argc == 5) && !strncmp(argv[1], "poll", strlen(argv[1]))) {
-		/* set polling params */
-		int32_t new_max_poll_ms = atoi(argv[2]);
-		int32_t new_min_poll_ms = atoi(argv[3]);
-		int32_t new_max_poll_errs = atoi(argv[4]);
-		if ((new_max_poll_ms >= 0) && (new_min_poll_ms >= 0) && (new_max_poll_errs >= 0)
-			 && (new_max_poll_ms >= new_min_poll_ms)) {
-			rtt_max_poll_ms = new_max_poll_ms;
-			rtt_min_poll_ms = new_min_poll_ms;
-			rtt_max_poll_errs = new_max_poll_errs;
+		rtt_ident[sizeof(rtt_ident) - 1] = '\0';
+		for (size_t i = 0; i < sizeof(rtt_ident); i++) {
+			if (rtt_ident[i] == '_')
+				rtt_ident[i] = ' ';
 		}
-		else gdb_out("how?\n");
-	}
-	else gdb_out("what?\n");
+	} else if (argc == 5 && !strncmp(argv[1], "poll", command_len)) {
+		/* set polling params */
+		rtt_max_poll_ms = strtoul(argv[2], NULL, 0);
+		rtt_min_poll_ms = strtoul(argv[3], NULL, 0);
+		rtt_max_poll_errs = strtoul(argv[4], NULL, 0);
+	} else
+		gdb_out("what?\n");
 	return true;
 }
 #endif