diff --git a/lib/compiler/CMakeLists.txt b/lib/compiler/CMakeLists.txt
index 97ba9ac..885b88c 100644
--- a/lib/compiler/CMakeLists.txt
+++ b/lib/compiler/CMakeLists.txt
@@ -1,3 +1,4 @@
+add_subdirectory (armcc)
 add_subdirectory (gcc)
 add_subdirectory (iar)
 
diff --git a/lib/compiler/armcc/CMakeLists.txt b/lib/compiler/armcc/CMakeLists.txt
new file mode 100644
index 0000000..9c93d81
--- /dev/null
+++ b/lib/compiler/armcc/CMakeLists.txt
@@ -0,0 +1,3 @@
+collect (PROJECT_LIB_HEADERS errno.h)
+
+# vim: expandtab:ts=2:sw=2:smartindent
diff --git a/lib/compiler/armcc/errno.h b/lib/compiler/armcc/errno.h
new file mode 100644
index 0000000..43dab85
--- /dev/null
+++ b/lib/compiler/armcc/errno.h
@@ -0,0 +1,58 @@
+/*-
+ * Copyright (c) 2020 STMicroelectronics. All rights reserved.
+ *
+ * Copyright (c) 1982, 1986, 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * (c) UNIX System Laboratories, Inc.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __METAL_ARMCC_ERRNO__H__
+#define __METAL_ARMCC_ERRNO__H__
+
+#include <errno.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define LIBMETAL_ERR_BASE  100
+
+#define	EPERM	(LIBMETAL_ERR_BASE + 1)  /* Operation not permitted */
+#define	ENOENT	(LIBMETAL_ERR_BASE + 2)  /* No such file or directory */
+#define	ESRCH	(LIBMETAL_ERR_BASE + 3)  /* No such process */
+#define	EINTR	(LIBMETAL_ERR_BASE + 4)  /* Interrupted system call */
+#define	EIO	(LIBMETAL_ERR_BASE + 5)  /* Input/output error */
+#define	ENXIO	(LIBMETAL_ERR_BASE + 6)  /* Device not configured */
+#define	E2BIG	(LIBMETAL_ERR_BASE + 7)  /* Argument list too long */
+#define	ENOEXEC	(LIBMETAL_ERR_BASE + 8)  /* Exec format error */
+#define	EBADF	(LIBMETAL_ERR_BASE + 9)  /* Bad file descriptor */
+#define	ECHILD	(LIBMETAL_ERR_BASE + 10) /* No child processes */
+#define	EDEADLK	(LIBMETAL_ERR_BASE + 11) /* Resource deadlock avoided */
+#define	EACCES	(LIBMETAL_ERR_BASE + 13) /* Permission denied */
+#define	EFAULT	(LIBMETAL_ERR_BASE + 14) /* Bad address */
+#define	ENOTBLK	(LIBMETAL_ERR_BASE + 15) /* Block device required */
+#define	EBUSY	(LIBMETAL_ERR_BASE + 16) /* Device busy */
+#define	EEXIST	(LIBMETAL_ERR_BASE + 17) /* File exists */
+#define	EXDEV	(LIBMETAL_ERR_BASE + 18) /* Cross-device link */
+#define	ENODEV	(LIBMETAL_ERR_BASE + 19) /* Operation not supported by device */
+#define	ENOTDIR	(LIBMETAL_ERR_BASE + 20) /* Not a directory */
+#define	EISDIR	(LIBMETAL_ERR_BASE + 21) /* Is a directory */
+#define	ENFILE	(LIBMETAL_ERR_BASE + 23) /* Too many open files in system */
+#define	EMFILE	(LIBMETAL_ERR_BASE + 24) /* Too many open files */
+#define	ENOTTY	(LIBMETAL_ERR_BASE + 25) /* Inappropriate ioctl for device */
+#define	ETXTBSY	(LIBMETAL_ERR_BASE + 26) /* Text file busy */
+#define	EFBIG	(LIBMETAL_ERR_BASE + 27) /* File too large */
+#define	ENOSPC	(LIBMETAL_ERR_BASE + 28) /* No space left on device */
+#define	ESPIPE	(LIBMETAL_ERR_BASE + 29) /* Illegal seek */
+#define	EROFS	(LIBMETAL_ERR_BASE + 30) /* Read-only filesystem */
+#define	EMLINK	(LIBMETAL_ERR_BASE + 31) /* Too many links */
+#define	EPIPE	(LIBMETAL_ERR_BASE + 32) /* Broken pipe */
+#define	EAGAIN	(LIBMETAL_ERR_BASE + 35) /* Resource temporarily unavailable */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __METAL_ARMCC_ERRNO__H__ */
diff --git a/lib/errno.h b/lib/errno.h
index fb4997e..e84a2bc 100644
--- a/lib/errno.h
+++ b/lib/errno.h
@@ -14,6 +14,8 @@
 
 #if defined(__ICCARM__)
 # include <metal/compiler/iar/errno.h>
+#elif defined(__CC_ARM)
+# include <metal/compiler/armcc/errno.h>
 #else
 # include <errno.h>
 #endif