diff --git a/library/platform.c b/library/platform.c
index a295f9b..d177449 100644
--- a/library/platform.c
+++ b/library/platform.c
@@ -98,6 +98,111 @@
 }
 #endif
 
+#if defined(MBEDTLS_PLATFORM_TF_SNPRINTF)
+
+static void unsigned_dec_print( char **s, size_t n, size_t *chars_printed,
+                                unsigned int unum )
+{
+    /* Enough for a 32-bit unsigned decimal integer (4294967295). */
+    unsigned char num_buf[10];
+    int i = 0, rem;
+
+    do
+    {
+        rem = unum % 10;
+        num_buf[i++] = '0' + rem;
+    } while( unum /= 10 );
+
+    while( --i >= 0 )
+    {
+        if( *chars_printed < n )
+            *(*s)++ = num_buf[i];
+        (*chars_printed)++;
+    }
+}
+
+int tf_snprintf( char *s, size_t n, const char *fmt, ... )
+{
+    va_list args;
+    int num;
+    unsigned int unum;
+    size_t chars_printed = 0;
+
+    if( n == 1 )
+    {
+        /* Buffer is too small to actually write anything else. */
+        *s = '\0';
+        n = 0;
+    }
+    else if( n >= 2 )
+    {
+        /* Reserve space for the terminator character. */
+        n--;
+    }
+
+    va_start( args, fmt );
+    while( *fmt ) {
+
+        if( *fmt == '%' )
+        {
+            fmt++;
+            /* Check the format specifier. */
+            switch( *fmt )
+            {
+            case 'i':
+            case 'd':
+                num = va_arg( args, int );
+
+                if( num < 0 )
+                {
+                    if( chars_printed < n )
+                        *s++ = '-';
+                    chars_printed++;
+
+                    unum = (unsigned int)-num;
+                }
+                else
+                {
+                    unum = (unsigned int)num;
+                }
+
+                unsigned_dec_print( &s, n, &chars_printed, unum );
+                break;
+            case 'u':
+                unum = va_arg( args, unsigned int );
+                unsigned_dec_print( &s, n, &chars_printed, unum );
+                break;
+            default:
+                /* Return error on any other specifier. */
+                chars_printed = -1;
+                goto exit;
+            }
+            fmt++;
+            continue;
+        }
+
+        if( chars_printed < n )
+            *s++ = *fmt;
+        fmt++;
+        chars_printed++;
+    }
+
+exit:
+    va_end( args );
+
+    if( n > 0 )
+        *s = '\0';
+
+    return( chars_printed );
+}
+
+#if defined(MBEDTLS_PLATFORM_STD_SNPRINTF)
+#undef MBEDTLS_PLATFORM_STD_SNPRINTF
+#endif
+#define MBEDTLS_PLATFORM_STD_SNPRINTF tf_snprintf;
+
+#endif /* MBEDTLS_PLATFORM_TF_SNPRINTF */
+
 #if defined(MBEDTLS_PLATFORM_SNPRINTF_ALT)
 #if !defined(MBEDTLS_PLATFORM_STD_SNPRINTF)
 /*