diff --git a/hal/armv7a/string.c b/hal/armv7a/string.c
index 8fc36ae1d..43b962e49 100644
--- a/hal/armv7a/string.c
+++ b/hal/armv7a/string.c
@@ -176,9 +176,14 @@ unsigned long hal_i2s(const char *prefix, char *s, unsigned long i, unsigned cha
 	m = hal_strlen(prefix);
 	hal_memcpy(s, prefix, m);
 
-	for (k = m, l = (unsigned long)-1; l; i /= b, l /= b) {
-		if (!zero && !i)
+	if ((zero == 0) && (i == 0)) {
+		s[m++] = '0';
+	}
+
+	for (k = m, l = (unsigned long)-1; l != 0; i /= b, l /= b) {
+		if ((zero == 0) && (i == 0)) {
 			break;
+		}
 		s[k++] = digits[i % b];
 	}
 
diff --git a/hal/armv7m/string.c b/hal/armv7m/string.c
index 8ad10d8d8..ad3d8cd86 100644
--- a/hal/armv7m/string.c
+++ b/hal/armv7m/string.c
@@ -177,9 +177,14 @@ unsigned long hal_i2s(const char *prefix, char *s, unsigned long i, unsigned cha
 	m = hal_strlen(prefix);
 	hal_memcpy(s, prefix, m);
 
-	for (k = m, l = (unsigned long)-1; l; i /= b, l /= b) {
-		if (!zero && !i)
+	if ((zero == 0) && (i == 0)) {
+		s[m++] = '0';
+	}
+
+	for (k = m, l = (unsigned long)-1; l != 0; i /= b, l /= b) {
+		if ((zero == 0) && (i == 0)) {
 			break;
+		}
 		s[k++] = digits[i % b];
 	}
 
diff --git a/hal/armv8m/string.c b/hal/armv8m/string.c
index 4e62b74c3..4340ed993 100644
--- a/hal/armv8m/string.c
+++ b/hal/armv8m/string.c
@@ -178,8 +178,12 @@ unsigned long hal_i2s(const char *prefix, char *s, unsigned long i, unsigned cha
 	m = hal_strlen(prefix);
 	hal_memcpy(s, prefix, m);
 
-	for (k = m, l = (unsigned long)-1; l; i /= b, l /= b) {
-		if (!zero && !i) {
+	if ((zero == 0) && (i == 0)) {
+		s[m++] = '0';
+	}
+
+	for (k = m, l = (unsigned long)-1; l != 0; i /= b, l /= b) {
+		if ((zero == 0) && (i == 0)) {
 			break;
 		}
 		s[k++] = digits[i % b];
diff --git a/hal/ia32/string.c b/hal/ia32/string.c
index 8e73c85ab..0fc61efe6 100644
--- a/hal/ia32/string.c
+++ b/hal/ia32/string.c
@@ -40,13 +40,15 @@ void hal_memcpy(void *dst, const void *src, size_t l)
 
 int hal_memcmp(const void *ptr1, const void *ptr2, size_t num)
 {
-	int i;
+	size_t i;
 
 	for (i = 0; i < num; ++i) {
-		if (((const u8 *)ptr1)[i] < ((const u8 *)ptr2)[i])
+		if (((const u8 *)ptr1)[i] < ((const u8 *)ptr2)[i]) {
 			return -1;
-		else if (((const u8 *)ptr1)[i] > ((const u8 *)ptr2)[i])
+		}
+		else if (((const u8 *)ptr1)[i] > ((const u8 *)ptr2)[i]) {
 			return 1;
+		}
 	}
 
 	return 0;
@@ -85,10 +87,11 @@ void hal_memset(void *dst, int v, size_t l)
 
 size_t hal_strlen(const char *s)
 {
-	unsigned int k;
+	size_t k;
 
-	for (k = 0; *s; s++, k++)
+	for (k = 0; *s; s++, k++) {
 		;
+	}
 
 	return k;
 }
@@ -99,18 +102,21 @@ int hal_strcmp(const char *s1, const char *s2)
 	const unsigned char *us1 = (const unsigned char *)s1;
 	const unsigned char *us2 = (const unsigned char *)s2;
 	const unsigned char *p;
-	unsigned int k;
+	size_t k;
 
 	for (p = us1, k = 0; *p; p++, k++) {
 
-		if (*p < *(us2 + k))
+		if (*p < *(us2 + k)) {
 			return -1;
-		else if (*p > *(us2 + k))
+		}
+		else if (*p > *(us2 + k)) {
 			return 1;
+		}
 	}
 
-	if (*p != *(us2 + k))
+	if (*p != *(us2 + k)) {
 		return -1;
+	}
 
 	return 0;
 }
@@ -120,13 +126,15 @@ int hal_strncmp(const char *s1, const char *s2, size_t count)
 {
 	const unsigned char *us1 = (const unsigned char *)s1;
 	const unsigned char *us2 = (const unsigned char *)s2;
-	unsigned int k;
+	size_t k;
 
-	for (k = 0; k < count && *us1 && *us2 && (*us1 == *us2); ++k, ++us1, ++us2)
+	for (k = 0; (k < count) && (*us1 != 0) && (*us2 != 0) && (*us1 == *us2); ++k, ++us1, ++us2) {
 		;
+	}
 
-	if (k == count || (!*us1 && !*us2))
+	if ((k == count) || ((*us1 == 0) && (*us2 == 0))) {
 		return 0;
+	}
 
 	return (*us1 < *us2) ? -k - 1 : k + 1;
 }
@@ -134,7 +142,7 @@ int hal_strncmp(const char *s1, const char *s2, size_t count)
 
 char *hal_strcpy(char *dest, const char *src)
 {
-	int i = 0;
+	size_t i = 0;
 
 	do {
 		dest[i] = src[i];
@@ -146,15 +154,16 @@ char *hal_strcpy(char *dest, const char *src)
 
 char *hal_strncpy(char *dest, const char *src, size_t n)
 {
-	int i = 0;
+	size_t i = 0;
 
-	if (n == 0)
+	if (n == 0) {
 		return dest;
+	}
 
 	do {
 		dest[i] = src[i];
 		i++;
-	} while (i < n && src[i - 1] != '\0');
+	} while ((i < n) && (src[i - 1] != '\0'));
 
 	return dest;
 }
@@ -169,9 +178,14 @@ unsigned long hal_i2s(const char *prefix, char *s, unsigned long i, unsigned cha
 	m = hal_strlen(prefix);
 	hal_memcpy(s, prefix, m);
 
-	for (k = m, l = (unsigned long)-1; l; i /= b, l /= b) {
-		if (!zero && !i)
+	if ((zero == 0) && (i == 0)) {
+		s[m++] = '0';
+	}
+
+	for (k = m, l = (unsigned long)-1; l != 0; i /= b, l /= b) {
+		if ((zero == 0) && (i == 0)) {
 			break;
+		}
 		s[k++] = digits[i % b];
 	}
 
diff --git a/hal/riscv64/string.c b/hal/riscv64/string.c
index e58020548..4a8dea5a0 100644
--- a/hal/riscv64/string.c
+++ b/hal/riscv64/string.c
@@ -19,13 +19,15 @@
 
 int hal_memcmp(const void *ptr1, const void *ptr2, size_t num)
 {
-	int i;
+	size_t i;
 
 	for (i = 0; i < num; ++i) {
-		if (((const u8 *)ptr1)[i] < ((const u8 *)ptr2)[i])
+		if (((const u8 *)ptr1)[i] < ((const u8 *)ptr2)[i]) {
 			return -1;
-		else if (((const u8 *)ptr1)[i] > ((const u8 *)ptr2)[i])
+		}
+		else if (((const u8 *)ptr1)[i] > ((const u8 *)ptr2)[i]) {
 			return 1;
+		}
 	}
 
 	return 0;
@@ -36,8 +38,9 @@ size_t hal_strlen(const char *s)
 {
 	size_t k;
 
-	for (k = 0; *s; s++, k++)
+	for (k = 0; *s; s++, k++) {
 		;
+	}
 
 	return k;
 }
@@ -48,18 +51,21 @@ int hal_strcmp(const char *s1, const char *s2)
 	const unsigned char *us1 = (const unsigned char *)s1;
 	const unsigned char *us2 = (const unsigned char *)s2;
 	const unsigned char *p;
-	unsigned int k;
+	size_t k;
 
 	for (p = us1, k = 0; *p; p++, k++) {
 
-		if (*p < *(us2 + k))
+		if (*p < *(us2 + k)) {
 			return -1;
-		else if (*p > *(us2 + k))
+		}
+		else if (*p > *(us2 + k)) {
 			return 1;
+		}
 	}
 
-	if (*p != *(us2 + k))
+	if (*p != *(us2 + k)) {
 		return -1;
+	}
 
 	return 0;
 }
@@ -71,10 +77,13 @@ int hal_strncmp(const char *s1, const char *s2, size_t count)
 	const unsigned char *us2 = (const unsigned char *)s2;
 	size_t k;
 
-	for (k = 0; k < count && *us1 && *us2 && (*us1 == *us2); ++k, ++us1, ++us2);
+	for (k = 0; (k < count) && (*us1 != 0) && (*us2 != 0) && (*us1 == *us2); ++k, ++us1, ++us2) {
+		;
+	}
 
-	if (k == count || (!*us1 && !*us2))
+	if ((k == count) || ((*us1 == 0) && (*us2 == 0))) {
 		return 0;
+	}
 
 	return (*us1 < *us2) ? -k - 1 : k + 1;
 }
@@ -82,7 +91,7 @@ int hal_strncmp(const char *s1, const char *s2, size_t count)
 
 char *hal_strcpy(char *dest, const char *src)
 {
-	int i = 0;
+	size_t i = 0;
 
 	do {
 		dest[i] = src[i];
@@ -94,15 +103,16 @@ char *hal_strcpy(char *dest, const char *src)
 
 char *hal_strncpy(char *dest, const char *src, size_t n)
 {
-	int i = 0;
+	size_t i = 0;
 
-	if (n == 0)
+	if (n == 0) {
 		return dest;
+	}
 
 	do {
 		dest[i] = src[i];
 		i++;
-	} while (i < n && src[i - 1] != '\0');
+	} while ((i < n) && (src[i - 1] != '\0'));
 
 	return dest;
 }
@@ -117,9 +127,14 @@ unsigned long hal_i2s(const char *prefix, char *s, unsigned long i, unsigned cha
 	m = hal_strlen(prefix);
 	hal_memcpy(s, prefix, m);
 
-	for (k = m, l = (unsigned long)-1; l; i /= b, l /= b) {
-		if (!zero && !i)
+	if ((zero == 0) && (i == 0)) {
+		s[m++] = '0';
+	}
+
+	for (k = m, l = (unsigned long)-1; l != 0; i /= b, l /= b) {
+		if ((zero == 0) && (i == 0)) {
 			break;
+		}
 		s[k++] = digits[i % b];
 	}
 
diff --git a/hal/sparcv8leon3/string.c b/hal/sparcv8leon3/string.c
index 4c608ac47..5048fcf9b 100644
--- a/hal/sparcv8leon3/string.c
+++ b/hal/sparcv8leon3/string.c
@@ -282,14 +282,19 @@ unsigned long hal_i2s(const char *prefix, char *s, unsigned long i, unsigned cha
 {
 	static const char digits[] = "0123456789abcdef";
 	char c;
-	unsigned int l, k, m;
+	unsigned long l, k, m;
 
 	m = hal_strlen(prefix);
 	hal_memcpy(s, prefix, m);
 
-	for (k = m, l = (unsigned int)-1; l; i /= b, l /= b) {
-		if (!zero && !i)
+	if ((zero == 0) && (i == 0)) {
+		s[m++] = '0';
+	}
+
+	for (k = m, l = (unsigned long)-1; l != 0; i /= b, l /= b) {
+		if ((zero == 0) && (i == 0)) {
 			break;
+		}
 		s[k++] = digits[i % b];
 	}