Implement most of the string.c functions.

src/string.c

@@ -1,22 +1,33 @@
 #include "string.h"
 
-int memcmp(const void *s1, const void *s2, usize n)
+int memcmp(const void *m1, const void *m2, usize n)
 {
-	/* TODO: Compare n bytes of s1 with s2, performing *s1-*s2.
-	 * Returning if non-zero or out of bounds. */
+	const u8 *s1 = m1, *s2 = m2;
+
+	int v = 0;
+	while (n > 0 && !(v = *s1 - *s2))
+		s1++, s2++, n--;
+	return v;
 }
 
-void *memset(void *s, int c, usize n)
+void *memset(void *m, int c, usize n)
 {
-	/* TODO: Fill memory with c */
+	u8 *s = m;
+	for (; n > 0; n--)
+		*(s++) = c;
+	return m;
 }
 
 void *memcpy(void *restrict dst, const void *restrict src, usize n)
 {
-	/* TODO: Copies memory area, not allowing overlap */
+	const u8 *ssrc = src;
+	u8       *sdst = dst;
+	for (; n > 0; n--)
+		*(sdst++) = *(ssrc++);
+	return dst;
 }
 
 void *memmove(void *dst, const void *src, usize n)
 {
-	/* TODO: Moves memory area, allowing overlap */
+	/* TODO: Moves memory area, allowing overlap. As though an array is used. */
 }