; ; Ullrich von Bassewitz, 2003-04-13 ; ; clock_t clock (void); ; .export _clock .import negax .importzp sreg .include "atmos.inc" .proc _clock ; Clear the timer high 16 bits ldy #$00 sty sreg sty sreg+1 ; Read the timer sei ; Disable interrupts lda TIMER3 ldx TIMER3+1 cli ; Reenable interrupts ; Since the timer is counting downwards, return the negated value jmp negax .endproc