+static uint8_t
+ao_cmd_hex_nibble(void)
+{
+ if ('0' <= ao_cmd_lex_c && ao_cmd_lex_c <= '9')
+ return ao_cmd_lex_c - '0';
+ if ('a' <= ao_cmd_lex_c && ao_cmd_lex_c <= 'f')
+ return ao_cmd_lex_c - ('a' - 10);
+ if ('A' <= ao_cmd_lex_c && ao_cmd_lex_c <= 'F')
+ return ao_cmd_lex_c - ('A' - 10);
+ ao_cmd_status = ao_cmd_syntax_error;
+ return 0;
+}
+