diff --git a/CMakeLists.txt b/CMakeLists.txt
index dd2baa6..84fdb18 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,7 +58,9 @@ endif()
 # Building
 
 set(SOURCES
+  # assert
   src/libc/assert/assert.c
+  # ctype
   src/libc/ctype/isalnum.c
   src/libc/ctype/isalpha.c
   src/libc/ctype/isblank.c
@@ -73,9 +75,12 @@ set(SOURCES
   src/libc/ctype/isxdigit.c
   src/libc/ctype/tolower.c
   src/libc/ctype/toupper.c
+  # errno
   src/libc/errno/errno.c
+  # locale
   src/libc/locale/setlocale.c
   src/libc/locale/localeconv.c
+  # stdio
   src/libc/stdio/vsnprintf.c
   src/libc/stdio/sprintf.c
   src/libc/stdio/dprintf.c
@@ -89,8 +94,16 @@ set(SOURCES
   src/libc/stdio/internal/printf.h
   src/libc/stdio/vdprintf.c
   src/libc/stdio/printf.c
+  # stdlib
+  src/libc/stdlib/abs.c
   src/libc/stdlib/calloc.c
+  src/libc/stdlib/div.c
+  src/libc/stdlib/labs.c
+  src/libc/stdlib/ldiv.c
+  src/libc/stdlib/llabs.c
+  src/libc/stdlib/lldiv.c
   src/libc/stdlib/reallocarray.c
+  # string
   src/libc/string/strchr.c
   src/libc/string/strcpy.c
   src/libc/string/memcpy.c
diff --git a/STATUS b/STATUS
index f6daea7..10e883b 100644
--- a/STATUS
+++ b/STATUS
@@ -95,7 +95,15 @@ DONE:       Function/symbol/macro is defined, builds, links, and is tested
      TODO (will give the full list later on)
 
 7.20 <stdlib.h>
-     TODO (will give the full list later on)
+     7.20.1  Numeric conversion functions: TODO
+     7.20.2  Pseudo-random sequence generation functions: TODO
+     7.20.3  Memory management functions: TODO (check existing code first)
+     7.20.4  Communication with the environment: TODO
+     7.20.5  Searching and sorting utilities: TODO
+     7.20.6.1  abs, labs, llabs: TEST
+     7.20.6.2  div, ldiv, lldiv: TEST
+     7.20.7  Multibyte/wide character conversion functions: TODO
+     7.20.8  Multibyte/wide string conversion functions: TODO
 
 7.21 <string.h>
      TODO (will give the full list later on)
diff --git a/include/stdlib.h b/include/stdlib.h
index b087499..8dd0dd5 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -4,9 +4,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
-//---
-// Dynamic memory management
-//---
+/* Dynamic memory management. */
+
 /* Allocate SIZE bytes of memory. */
 extern void *malloc(size_t size);
 
@@ -28,4 +27,40 @@ extern void *reallocarray(void *ptr, size_t nmemb, size_t size);
 /* Free a block allocated by `malloc', `realloc' or `calloc'. */
 extern void free(void *ptr);
 
+/* Integer arithmetic functions. */
+
+extern int abs(int __j);
+#define abs(j) ({ \
+	int __j = (j); \
+	(__j >= 0) ? __j : -(__j); \
+})
+
+extern long int labs(long int __j);
+#define labs(j) ({ \
+	long int __j = (j); \
+	(__j >= 0) ? __j : -(__j); \
+})
+
+extern long long int llabs(long long int __j);
+#define llabs(j) ({ \
+	long long int __j = (j); \
+	(__j >= 0) ? __j : -(__j); \
+})
+
+typedef struct {
+	int quot, rem;
+} div_t;
+
+typedef struct {
+	long int quot, rem;
+} ldiv_t;
+
+typedef struct {
+	long long int quot, rem;
+} lldiv_t;
+
+div_t div(int __num, int __denom);
+ldiv_t ldiv(long int __num, long int __denom);
+lldiv_t lldiv(long long int __num, long long int __denom);
+
 #endif /*__STDLIB_H__*/
diff --git a/src/libc/stdlib/abs.c b/src/libc/stdlib/abs.c
new file mode 100644
index 0000000..bc6b856
--- /dev/null
+++ b/src/libc/stdlib/abs.c
@@ -0,0 +1,7 @@
+#include <stdlib.h>
+#undef abs
+
+int abs(int j)
+{
+	return (j >= 0) ? j : -j;
+}
diff --git a/src/libc/stdlib/div.c b/src/libc/stdlib/div.c
new file mode 100644
index 0000000..48be8a4
--- /dev/null
+++ b/src/libc/stdlib/div.c
@@ -0,0 +1,12 @@
+#include <stdlib.h>
+
+div_t div(int num, int denom)
+{
+	/*
+	** On SuperH, division and modulus are both very slow, so it's more
+	** efficient to perform only one division.
+	*/
+	int q = num / denom;
+	int r = num - q * denom;
+	return (div_t){ q, r };
+}
diff --git a/src/libc/stdlib/labs.c b/src/libc/stdlib/labs.c
new file mode 100644
index 0000000..d060f3a
--- /dev/null
+++ b/src/libc/stdlib/labs.c
@@ -0,0 +1,7 @@
+#include <stdlib.h>
+#undef labs
+
+long int labs(long int j)
+{
+	return (j >= 0) ? j : -j;
+}
diff --git a/src/libc/stdlib/ldiv.c b/src/libc/stdlib/ldiv.c
new file mode 100644
index 0000000..0570517
--- /dev/null
+++ b/src/libc/stdlib/ldiv.c
@@ -0,0 +1,8 @@
+#include <stdlib.h>
+
+ldiv_t ldiv(long int num, long int denom)
+{
+	long int q = num / denom;
+	long int r = num - q * denom;
+	return (ldiv_t){ q, r };
+}
diff --git a/src/libc/stdlib/llabs.c b/src/libc/stdlib/llabs.c
new file mode 100644
index 0000000..f4d01a8
--- /dev/null
+++ b/src/libc/stdlib/llabs.c
@@ -0,0 +1,7 @@
+#include <stdlib.h>
+#undef llabs
+
+long long int llabs(long long int j)
+{
+	return (j >= 0) ? j : -j;
+}
diff --git a/src/libc/stdlib/lldiv.c b/src/libc/stdlib/lldiv.c
new file mode 100644
index 0000000..27adfde
--- /dev/null
+++ b/src/libc/stdlib/lldiv.c
@@ -0,0 +1,8 @@
+#include <stdlib.h>
+
+lldiv_t lldiv(long long int num, long long int denom)
+{
+	long long int q = num / denom;
+	long long int r = num - q * denom;
+	return (lldiv_t){ q, r };
+}