Add mem functions

lib/src/libgcc/memcmp.c

@@ -0,0 +1,13 @@
+/* Public domain.  */
+#include <ultra64.h>
+
+int memcmp(const void *str1, const void *str2, size_t count) {
+    const unsigned char *s1 = str1;
+    const unsigned char *s2 = str2;
+
+    while (count-- > 0) {
+        if (*s1++ != *s2++)
+            return s1[-1] < s2[-1] ? -1 : 1;
+    }
+    return 0;
+}

lib/src/libgcc/memmove.c

@@ -0,0 +1,17 @@
+/* Public domain.  */
+#include <ultra64.h>
+
+void *memmove(void *dest, const void *src, size_t len) {
+    char *d = dest;
+    const char *s = src;
+    if (d < s)
+        while (len--)
+            *d++ = *s++;
+    else {
+        char *lasts = (char *) s + (len - 1);
+        char *lastd = (char *) d + (len - 1);
+        while (len--)
+            *lastd-- = *lasts--;
+    }
+    return dest;
+}

lib/src/libgcc/memset.c

@@ -0,0 +1,9 @@
+/* Public domain.  */
+#include <ultra64.h>
+
+void *memset(void *dest, int val, size_t len) {
+    unsigned char *ptr = dest;
+    while (len-- > 0)
+        *ptr++ = val;
+    return dest;
+}