diff --git a/simio/simio.c b/simio/simio.c
index 998a7ca..5ba12e7 100644
--- a/simio/simio.c
+++ b/simio/simio.c
@@ -341,7 +341,7 @@ IO_REQUEST_FUNC(static simio_read_b_device, read_b, uint8_t *)
 
 int simio_write_b(address_t addr, uint8_t data)
 {
-	if (addr >= 0 && addr < 16) {
+	if (addr < 16) {
 		sfr_data[addr] = data;
 		return 0;
 	}
@@ -351,7 +351,7 @@ int simio_write_b(address_t addr, uint8_t data)
 
 int simio_read_b(address_t addr, uint8_t *data)
 {
-	if (addr >= 0 && addr < 16) {
+	if (addr < 16) {
 		*data = sfr_data[addr];
 		return 0;
 	}
@@ -425,7 +425,7 @@ void simio_step(uint16_t status_register, int cycles)
 
 uint8_t simio_sfr_get(address_t which)
 {
-	if (which < 0 || which > sizeof(sfr_data))
+	if (which > sizeof(sfr_data))
 		return 0;
 
 	return sfr_data[which];
@@ -433,7 +433,7 @@ uint8_t simio_sfr_get(address_t which)
 
 void simio_sfr_modify(address_t which, uint8_t mask, uint8_t bits)
 {
-	if (which < 0 || which > sizeof(sfr_data))
+	if (which > sizeof(sfr_data))
 		return;
 
 	sfr_data[which] = (sfr_data[which] & ~mask) | bits;
diff --git a/simio/simio_gpio.c b/simio/simio_gpio.c
index 543a2e5..510c7a2 100644
--- a/simio/simio_gpio.c
+++ b/simio/simio_gpio.c
@@ -146,7 +146,7 @@ static int config_channel(struct gpio *g, char **arg_text)
 		return -1;
 	}
 
-	if (which < 0 || which > 7) {
+	if (which > 7) {
 		printc_err("gpio: invalid pin number: %d\n", which);
 		return -1;
 	}
diff --git a/simio/simio_timer.c b/simio/simio_timer.c
index a29ac23..bbbbaa1 100644
--- a/simio/simio_timer.c
+++ b/simio/simio_timer.c
@@ -192,7 +192,7 @@ static int config_channel(struct timer *tr, char **arg_text)
 		return -1;
 	}
 
-	if (which < 0 || which > tr->size) {
+	if (which > tr->size) {
 		printc_err("timer: invalid channel number: %d\n", which);
 		return -1;
 	}
diff --git a/simio/simio_tracer.c b/simio/simio_tracer.c
index e4540ea..6a30654 100644
--- a/simio/simio_tracer.c
+++ b/simio/simio_tracer.c
@@ -214,7 +214,7 @@ static int tracer_config(struct simio_device *dev,
 			return -1;
 		}
 
-		if (value < 0 || value >= 16) {
+		if (value >= 16) {
 			printc_err("tracer: trigger: invalid IRQ: %d\n",
 				   value);
 			return -1;
diff --git a/util/dis.c b/util/dis.c
index b18428b..932d54b 100644
--- a/util/dis.c
+++ b/util/dis.c
@@ -1007,7 +1007,7 @@ int dis_reg_from_name(const char *name)
 
 const char *dis_reg_name(msp430_reg_t reg)
 {
-	if (reg >= 0 && reg <= 15)
+	if (reg <= 15)
 		return msp430_reg_names[reg];
 
 	return NULL;
diff --git a/util/expr.c b/util/expr.c
index bdc1fc1..9c0c889 100644
--- a/util/expr.c
+++ b/util/expr.c
@@ -233,7 +233,6 @@ static int addr_exp_finish(struct addr_exp_state *s, address_t *ret)
 int expr_eval(const char *text, address_t *addr)
 {
 	const char *text_save = text;
-	int last_cc = 1;
 	char token_buf[64];
 	int token_len = 0;
 	struct addr_exp_state s = {0};
@@ -281,7 +280,6 @@ int expr_eval(const char *text, address_t *addr)
 		if (!*text)
 			break;
 
-		last_cc = cc;
 		text++;
 	}
 
diff --git a/util/output_util.c b/util/output_util.c
index e042546..485f873 100644
--- a/util/output_util.c
+++ b/util/output_util.c
@@ -27,7 +27,6 @@
 static int format_addr(msp430_amode_t amode, uint16_t addr)
 {
 	char name[64];
-	int numeric = 0;
 	const char *prefix = "";
 
 	switch (amode) {
@@ -39,7 +38,6 @@ static int format_addr(msp430_amode_t amode, uint16_t addr)
 	case MSP430_AMODE_IMMEDIATE:
 		prefix = "#";
 	case MSP430_AMODE_INDEXED:
-		numeric = 1;
 		break;
 
 	case MSP430_AMODE_ABSOLUTE: