Hi,
SeaBIOS seems to have a clock implementation in `src/clock.c` already, which is also used for threading, I guess. Could that be used for time stamps too or is there something in SeaBIOS, that would cause problems?
Better checkout src/hw/timer.c, you probably want use timer_read() + some TimerKHz math, then prefix each line with milliseconds-since-boot or something like that.
cheers, Gerd