diff --git a/targets/corstone-300/retarget.c b/targets/corstone-300/retarget.c
new file mode 100644
index 0000000..1598427
--- /dev/null
+++ b/targets/corstone-300/retarget.c
@@ -0,0 +1,256 @@
+/*
+ * Copyright (c) 2019-2020 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "uart.h"
+
+// armclang retargeting
+#if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6100100)
+#include <rt_misc.h>
+#include <rt_sys.h>
+
+/* Standard IO device handles. */
+#define STDIN  0x8001
+#define STDOUT 0x8002
+#define STDERR 0x8003
+
+#define RETARGET(fun) _sys##fun
+
+#else
+/*
+ * This type is used by the _ I/O functions to denote an open
+ * file.
+ */
+typedef int FILEHANDLE;
+
+/*
+ * Open a file. May return -1 if the file failed to open.
+ */
+extern FILEHANDLE _open(const char * /*name*/, int /*openmode*/);
+
+/* Standard IO device handles. */
+#define STDIN  0x00
+#define STDOUT 0x01
+#define STDERR 0x02
+
+#define RETARGET(fun) fun
+
+#endif
+
+/* Standard IO device name defines. */
+const char __stdin_name[] __attribute__((aligned(4)))  = "STDIN";
+const char __stdout_name[] __attribute__((aligned(4))) = "STDOUT";
+const char __stderr_name[] __attribute__((aligned(4))) = "STDERR";
+
+void _ttywrch(int ch) {
+    (void)fputc(ch, stdout);
+}
+
+FILEHANDLE RETARGET(_open)(const char *name, int openmode) {
+    (void)openmode;
+
+    if (strcmp(name, __stdin_name) == 0) {
+        return (STDIN);
+    }
+
+    if (strcmp(name, __stdout_name) == 0) {
+        return (STDOUT);
+    }
+
+    if (strcmp(name, __stderr_name) == 0) {
+        return (STDERR);
+    }
+
+    return -1;
+}
+
+int RETARGET(_write)(FILEHANDLE fh, const unsigned char *buf, unsigned int len, int mode) {
+    (void)mode;
+
+    switch (fh) {
+    case STDOUT:
+    case STDERR: {
+        int c;
+
+        while (len-- > 0) {
+            c = fputc(*buf++, stdout);
+            if (c == EOF) {
+                return EOF;
+            }
+        }
+
+        return 0;
+    }
+    default:
+        return EOF;
+    }
+}
+
+int RETARGET(_read)(FILEHANDLE fh, unsigned char *buf, unsigned int len, int mode) {
+    (void)mode;
+
+    switch (fh) {
+    case STDIN: {
+        int c;
+
+        while (len-- > 0) {
+            c = fgetc(stdin);
+            if (c == EOF) {
+                return EOF;
+            }
+
+            *buf++ = (unsigned char)c;
+        }
+
+        return 0;
+    }
+    default:
+        return EOF;
+    }
+}
+
+int RETARGET(_istty)(FILEHANDLE fh) {
+    switch (fh) {
+    case STDIN:
+    case STDOUT:
+    case STDERR:
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+int RETARGET(_close)(FILEHANDLE fh) {
+    if (RETARGET(_istty(fh))) {
+        return 0;
+    }
+
+    return -1;
+}
+
+int RETARGET(_seek)(FILEHANDLE fh, long pos) {
+    (void)fh;
+    (void)pos;
+
+    return -1;
+}
+
+int RETARGET(_ensure)(FILEHANDLE fh) {
+    (void)fh;
+
+    return -1;
+}
+
+long RETARGET(_flen)(FILEHANDLE fh) {
+    if (RETARGET(_istty)(fh)) {
+        return 0;
+    }
+
+    return -1;
+}
+
+int RETARGET(_tmpnam)(char *name, int sig, unsigned maxlen) {
+    (void)name;
+    (void)sig;
+    (void)maxlen;
+
+    return 1;
+}
+
+char *RETARGET(_command_string)(char *cmd, int len) {
+    (void)len;
+
+    return cmd;
+}
+
+void RETARGET(_exit)(int return_code) {
+    exit(return_code);
+}
+
+int system(const char *cmd) {
+    (void)cmd;
+
+    return 0;
+}
+
+time_t time(time_t *timer) {
+    time_t current;
+
+    current = 0; // To Do !! No RTC implemented
+
+    if (timer != NULL) {
+        *timer = current;
+    }
+
+    return current;
+}
+
+void _clock_init(void) {
+#if 0
+    // Example implementation based on SysTick
+    // For instance, use a counting var in a SysTick interrupt handler
+    // for clock() to use
+    SysTick->LOAD = (uint32_t) ((SystemCoreClock/100)-1UL);
+    NVIC_SetPriority (SysTick_IRQn, (1UL << __NVIC_PRIO_BITS) - 1UL);
+    SysTick->VAL = 0UL;
+    SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_TICKINT_Msk | SysTick_CTRL_ENABLE_Msk;
+#endif
+}
+
+clock_t clock(void) {
+    return (clock_t)-1;
+}
+
+int remove(const char *arg) {
+    (void)arg;
+    return 0;
+}
+
+int rename(const char *oldn, const char *newn) {
+    (void)oldn;
+    (void)newn;
+    return 0;
+}
+
+void exit(int code) {
+    uart_putc((char)0x4);
+    uart_putc((char)code);
+    while (1) {}
+}
+
+int fputc(int ch, FILE *f) {
+    (void)(f);
+    return uart_putc(ch);
+}
+
+int fgetc(FILE *f) {
+    (void)f;
+    return uart_putc(uart_getc());
+}
+
+#ifndef ferror
+/* arm-none-eabi-gcc with newlib uses a define for ferror */
+int ferror(FILE *f) {
+    (void)f;
+    return EOF;
+}
+#endif