diff --git a/include/string.h b/include/string.h
index 4905377..97e3e56 100644
--- a/include/string.h
+++ b/include/string.h
@@ -7,13 +7,15 @@
 
 #include <stddef.h>
 
-int memcpy(void *dst, const void *src, size_t amount);
+void* memcpy(void *dst, const void *src, size_t amount);
 
-int memset(void *dst, int data, size_t amount);
+void* memset(void *dst, int data, size_t amount);
 
-int strcpy(char *dst, const char *src);
+void *memmove(void *dst, const void *src, size_t amount);
 
-int strncpy(char *dst, const char *src, size_t n);
+void *strcpy(char *dst, const char *src);
+
+void *strncpy(char *dst, const char *src, size_t n);
 
 size_t strlen(const char *str);
 
diff --git a/kernel/debug/self_test.c b/kernel/debug/self_test.c
index 102245c..13121d3 100644
--- a/kernel/debug/self_test.c
+++ b/kernel/debug/self_test.c
@@ -101,7 +101,7 @@ void test_string() {
     const char *strcpy_src_test = "abc\0def";
     char *strcpy_dst_test = "\0\0\0\0\0\0\0";
     const char *strcpy_expected_test = "abc\0\0\0\0";
-    assert_int(0, strcpy(strcpy_dst_test, strcpy_src_test));
+    assert_ptr(strcpy_dst_test, strcpy(strcpy_dst_test, strcpy_src_test));
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wpointer-sign"
     assert_array_equal(strcpy_dst_test, strcpy_expected_test, 8);
diff --git a/kernel/libc/string.c b/kernel/libc/string.c
index b55b554..b058401 100644
--- a/kernel/libc/string.c
+++ b/kernel/libc/string.c
@@ -7,26 +7,35 @@
 #include <sys/types.h>
 #include <myke/mem/malloc.h>
 
-int memcpy(void *dst, const void *src, size_t amount) {
+void *memcpy(void *dst, const void *src, size_t amount) {
     for (size_t i = 0; i < amount; i++) {
         ((char *) dst)[i] = ((const char *) src)[i];
     }
-    return 0;
+    return dst;
 }
 
-int memset(void *dst, int data, size_t amount) {
+void *memset(void *dst, int data, size_t amount) {
     for (size_t i = 0; i < amount; ++i) {
         ((char *) dst)[i] = (char) data;
     }
-    return 0;
+    return dst;
 }
 
+void *memmove(void *dst, const void *src, size_t amount) {
+    void* tmp = malloc(amount);
+    if (tmp == NULL) {
+        return NULL;
+    }
+    memcpy(dst, memcpy(tmp, src, amount), amount);
+    free(tmp);
+    return dst;
+}
 
-int strcpy(char *dst, const char *src) {
+void *strcpy(char *dst, const char *src) {
     return memcpy(dst, src, strlen(src) + 1);
 }
 
-int strncpy(char *dst, const char *src, size_t n) {
+void *strncpy(char *dst, const char *src, size_t n) {
     return memcpy(dst, src, MIN(strlen(src), n) + 1);
 }
 
@@ -76,7 +85,7 @@ int memcmp(const void *s1, const void *s2, size_t n) {
         a = ((uint8_t *) s1)[i];
         b = ((uint8_t *) s2)[i];
         if (a > b) return 1;
-        if (b < a) return -1;
+        if (a < b) return -1;
     }
     return 0;
 }
@@ -120,12 +129,12 @@ char *strncat(char *dest, const char *src, size_t n) {
     return dest;
 }
 
-char* strdup(const char* s) {
+char *strdup(const char *s) {
     return strndup(s, strlen(s));
 }
 
-char* strndup(const char* s, size_t n) {
-    char* new = malloc(n + 1);
+char *strndup(const char *s, size_t n) {
+    char *new = malloc(n + 1);
     memcpy(new, s, n);
     new[n] = 0;
     return new;