\ Real Time Clock                                                    vandys
\ Requires Pentium rdtsc instruction
only drivers definitions

code rdtsc ( -- du )   $0F c, $31 c, \ rdtsc -> eax, edx
   eax push   edx push   next c;
$70 constant IO_RTC
$00 constant RTC_SEC
$0A constant RTC_STATUSA
   $80 constant RTCSA_TUP
create tsc1sec 0 , 0 ,   create tsc1msec 0 ,

: (rtcin) ( port -- u )   IO_RTC outb   $84 inb drop   IO_RTC 1+ inb
   $84 inb drop ;
: (wait_tup) ( -- )   begin   RTC_STATUSA (rtcin)   RTCSA_TUP and 0= until ;
: (wait_sec) ( sec -- sec' )   begin   (wait_tup) RTC_SEC (rtcin)
      2dup - if   nip exit   then   drop again ;
: calc_tscfreq ( -- )   (wait_tup) RTC_SEC (rtcin)
   (wait_sec)   rdtsc dnegate rot   (wait_sec) drop rdtsc d+
   2dup tsc1sec 2!    1000 um/mod tsc1msec ! drop ;

only