cc65/libsrc/atari7800/clocks_per_sec.s

;
; 2022-03-15, Karri Kaksonen
;
; clock_t __clocks_per_sec (void);
;

        .export         ___clocks_per_sec

        .import         sreg: zp
        .import         _paldetected
        .include        "atari7800.inc"

        .macpack        generic

        .code

;-----------------------------------------------------------------------------
; Return the number of clock ticks in one second.
;
        .proc   ___clocks_per_sec

        lda     #0
        tax
        sta     sreg            ; return 32 bits
        sta     sreg+1
        lda     _paldetected
        bne     pal
        lda     #60             ; NTSC - 60Hz
        rts
pal:
        lda     #50             ; PAL - 50Hz
        rts
        .endproc