diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7ce0749..59be0bf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -130,15 +130,17 @@ set(SOURCES
   src/libc/stdlib/strtoul.c
   src/libc/stdlib/strtoull.c
   # string
-  src/libc/string/strchr.c
-  src/libc/string/strcpy.c
   src/libc/string/memcpy.c
-  src/libc/string/strcat.c
   src/libc/string/memset.c
+  src/libc/string/strcat.c
+  src/libc/string/strchr.c
+  src/libc/string/strchrnul.c
   src/libc/string/strcmp.c
+  src/libc/string/strcpy.c
   src/libc/string/strdup.c
   src/libc/string/strlen.c
-  src/libc/string/strnlen.c)
+  src/libc/string/strnlen.c
+  src/libc/string/strrchr.c)
 
 if(vhex-generic IN_LIST TARGET_FOLDERS)
   # TODO
diff --git a/STATUS b/STATUS
index 60e6a7b..0d7275c 100644
--- a/STATUS
+++ b/STATUS
@@ -121,10 +121,10 @@ DONE:       Function/symbol/macro is defined, builds, links, and is tested
 !    7.21.4.4  strncmp: TODO
 !    7.21.4.5  strxfrm: TODO
      7.21.5.1  memchr: DONE
-!    7.21.5.2  strchr: TODO
+!    7.21.5.2  strchr: TEST
 !    7.21.5.3  strcspn: TODO
 !    7.21.5.4  strpbrk: TODO
-!    7.21.5.5  strrchr: TODO
+!    7.21.5.5  strrchr: TEST
 !    7.21.5.6  strspn: TODO
 !    7.21.5.7  strstr: TODO
 !    7.21.5.8  strtok: TODO
@@ -132,12 +132,12 @@ DONE:       Function/symbol/macro is defined, builds, links, and is tested
 !    7.21.6.2  strerror: TODO
      7.21.6.3  strlen: DONE
      Extensions:
-     - strnlen: TODO
-     - strchrnul: TODO
-     - strcasecmp: TODO
-     - strncasecmp: TODO
-     - strdup: TODO
-     - strndup: TODO
+!    - strnlen: TODO
+!    - strchrnul: TEST
+!    - strcasecmp: TODO
+!    - strncasecmp: TODO
+!    - strdup: TODO
+!    - strndup: TODO
 
 7.22 <tgmath.h> => GCC
 
diff --git a/src/libc/string/strchr.c b/src/libc/string/strchr.c
index 4d4af8a..5e89b1e 100644
--- a/src/libc/string/strchr.c
+++ b/src/libc/string/strchr.c
@@ -1,40 +1,10 @@
 #include <string.h>
 
-/*
-** The strchr() function returns a pointer to the first occurrence of the
-** character c in the strings.
-*/
-char *strchr(const char *s1, int c)
+char *strchr(char const *s, int c)
 {
-	int i = -1;
-	while (s1[++i] != '\0' && s1[i] != c) ;
-	return ((s1[i] == '\0') ? NULL : (void *)&s1[i]);
-}
-
-/*
-** The  strchrnul() function is like strchr() except that if c is not found in
-** s, then it returns a pointer to the null byte at the end of s, rather
-** than NULL.
-*/
-char *strchrnul(const char *s1, int c)
-{
-	int i = -1;
-	while (s1[++i] != '\0' && s1[i] != c) ;
-	return ((void *)&s1[i]);
-}
-
-/*
-** The strrchr() function returns a pointer to the last occurrence of the
-** character c in the strings.
-*/
-char *strrchr(const char *s1, int c)
-{
-	void *saved;
-
-	saved = NULL;
-	for (int i = 0; s1[i] != '\0'; i++) {
-		if (s1[i] == c)
-			saved = (void *)&s1[i];
+	for(size_t i = 0; s[i]; i++) {
+		if(s[i] == c) return (char *)&s[i];
 	}
-	return (saved);
+
+	return NULL;
 }
diff --git a/src/libc/string/strchrnul.c b/src/libc/string/strchrnul.c
new file mode 100644
index 0000000..8c9ade7
--- /dev/null
+++ b/src/libc/string/strchrnul.c
@@ -0,0 +1,12 @@
+#include <string.h>
+
+char *strchrnul(const char *s, int c)
+{
+	size_t i;
+
+	for(i = 0; s[i]; i++) {
+		if(s[i] == c) return (char *)&s[i];
+	}
+
+	return (char *)&s[i];
+}
diff --git a/src/libc/string/strrchr.c b/src/libc/string/strrchr.c
new file mode 100644
index 0000000..b1df1e8
--- /dev/null
+++ b/src/libc/string/strrchr.c
@@ -0,0 +1,12 @@
+#include <string.h>
+
+char *strrchr(char const *s, int c)
+{
+	void *last = NULL;
+
+	for(size_t i = 0; s[i]; i++) {
+		if(s[i] == c) last = (void *)&s[i];
+	}
+
+	return last;
+}