#include "xil_printf.h"
#include "xparameters.h"

#include "../hardware/interface_access.h"
#include "../hardware/interface_fds.h"


// newlib offers a (weak) write implementation which
// is reentrant by calling _write_r which in turn
// relies on _write which we implement here.
// This way, we get a global, reentrant write implementation
// NOTE: This might be architecture dependent, so check your
// newlib implementation!
int _write(int fd, const char *ptr, int len) {
  if (ptr == NULL) {
    return 0;
  }
  //TODO check len
  
  // 0 is stdin, do not write to it
  if (fd < 1) {
    return -1; // TODO error
  }
  // we only support a single debug UART, so
  // stdout and stderr are the same and go to the xiling stdout UART
  // We output directely to avoid loops and allow debugging (not via a write)
  if (fd < 3) {
    int todo;

    for (todo = 0; todo < len; todo++) {
      outbyte(*ptr++);
    }
    return len;
  }

  if (fd < INTERFACE_FDS_NEXT) {
    return hw_interface_write(fd, ptr, len);
  }

  // we do not have dynamic fds, so fd is invalid
  return -1;
}