feat: initial version

srcs/ft_memcpy64.c

@@ -0,0 +1,25 @@
+#include <stddef.h>
+#include <stdint.h>
+
+void *ft_memcpy64(void *dst, const void *src, size_t n) {
+    size_t i;
+    uint64_t *lp_dst;
+    const uint64_t *lp_src;
+    unsigned char *bp_dst;
+    const unsigned char *bp_src;
+
+    lp_dst = (uint64_t *)dst;
+    lp_src = (const uint64_t *)src;
+
+    for (i = 0; i < n / 8; i++) {
+        lp_dst[i] = lp_src[i];
+    }
+
+    bp_dst = (unsigned char *)(lp_dst + i);
+    bp_src = (const unsigned char *)(lp_src + i);
+    for (i = 0; i < n % 8; i++) {
+        bp_dst[i] = bp_src[i];
+    }
+
+    return dst;
+}