adds newlib-nano settings

newlib-nano/write.c

@@ -0,0 +1,24 @@
+#include <stdint.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include "stub.h"
+#include <platform.h>
+
+ssize_t _write(int fd, const void* ptr, size_t len);
+
+ssize_t _write(int fd, const void* ptr, size_t len) {
+  const char * current = (const char *)ptr;
+  if (isatty(fd)) {
+    for (size_t jj = 0; jj < len; jj++) {
+      while (uart_get_tx_free(uart)==0) ;
+      uart_write(uart, current[jj]);
+      if (current[jj] == '\n') {
+        while (uart_get_tx_free(uart)==0) ;
+        uart_write(uart, '\r');
+      }
+    }
+    return len;
+  }
+  return _stub(EBADF);
+}