VPRINTX
#define VPRINTX(regno) mov r0, regno; bl generic_printx
#define VPRINTX(regno) /* nothing */
#define VPRINTX(x) generic_printx(x)
#define VPRINTX(x) __nothing
#define VPRINTX(x) __nothing
#define VPRINTX(regno) \
#define VPRINTX(regno) /* nothing */