1 files changed, 51 insertions, 0 deletions

diff --git a/tmk_core/common/mbed/xprintf.cpp b/tmk_core/common/mbed/xprintf.cpp
new file mode 100644
index 000000000..3647ece75
--- /dev/null
+++ b/tmk_core/common/mbed/xprintf.cpp
@@ -0,0 +1,51 @@
+#include <cstdarg>
+//#include <stdarg.h>
+#include "mbed.h"
+#include "mbed/xprintf.h"
+
+
+#define STRING_STACK_LIMIT    120
+
+//TODO
+int xprintf(const char* format, ...) { return 0; }
+
+#if 0
+/* mbed Serial */
+Serial ser(UART_TX, UART_RX);
+
+/* TODO: Need small implementation for embedded */
+int xprintf(const char* format, ...)
+{
+    /* copy from mbed/common/RawSerial.cpp */
+    std::va_list arg;
+    va_start(arg, format);
+    int len = vsnprintf(NULL, 0, format, arg);
+    if (len < STRING_STACK_LIMIT) {
+        char temp[STRING_STACK_LIMIT];
+        vsprintf(temp, format, arg);
+        ser.puts(temp);
+    } else {
+        char *temp = new char[len + 1];
+        vsprintf(temp, format, arg);
+        ser.puts(temp);
+        delete[] temp;
+    }
+    va_end(arg);
+    return len;
+
+/* Fail: __builtin_va_arg_pack?
+ * https://gcc.gnu.org/onlinedocs/gcc-4.3.5/gcc/Constructing-Calls.html#Constructing-Calls
+    void *arg = __builtin_apply_args();
+    void *ret = __builtin_apply((void*)(&(ser.printf)), arg, 100);
+    __builtin_return(ret)
+*/
+/* Fail: varargs can not be passed to printf
+    //int r = ser.printf("test %i\r\n", 123);
+    va_list arg;
+    va_start(arg, format);
+    int r = ser.printf(format, arg);
+    va_end(arg);
+    return r;
+*/
+}
+#endif