+getchar(void) __reentrant __critical
+{
+ char c;
+ int8_t stdio = ao_cur_stdio;
+
+ for (;;) {
+ c = ao_stdios[stdio].pollchar();
+ if (c != AO_READ_AGAIN)
+ break;
+ if (++stdio == ao_num_stdios)
+ stdio = 0;
+ if (stdio == ao_cur_stdio)
+ ao_sleep(&ao_stdin_ready);
+ }
+ ao_cur_stdio = stdio;
+ return c;
+}
+
+uint8_t
+ao_echo(void)
+{
+ return ao_stdios[ao_cur_stdio].echo;
+}
+
+int8_t
+ao_add_stdio(char (*pollchar)(void),
+ void (*putchar)(char),
+ void (*flush)(void)) __reentrant