provide rtc-read

# real time clock support code

"rtc.pfo" pfo

"/dev/rtc" "r" open-file constant RTC


variable RTC-tickfreq


: RTC-tickfreq! 
  	dup RTC rtc-freq!
  	RTC-tickfreq ! ;

1024 RTC-tickfreq!

: ms>nbticks
	.001 *		# nb of seconds / period
	RTC-tickfreq @	# nb of ticks / second
	*	     	# nb of ticks / period
	.5 + >int	# round

	;
		

: rtc-flush
	try begin dup rtc-read again
	recover 2drop
	endtry ;

: rtc-block
	try rtc-read
	recover e_eof or-throw
		drop
		dup block-read
		pass rtc-block
   	endtry ;  

: RTC-ms-sync
	ms>nbticks
	dup if
	    for RTC rtc-block next 
	else
	    # need to yield at least once !!
	    block-poll 
	then ;


' RTC-ms-sync is ms-sync


"using RTC, with timer resolution:" p RTC-tickfreq @ p "Hz" p cr

# using 0.977 ms resolution. need this as root:
# mknod /dev/rtc c 10 135
# echo 1024 > /proc/sys/dev/rtc/max-user-freq