; Shared "how long to show the picture" epilogue for the simple C64 viewers.
; Selected at assembly time by WAITMODE (set by viewer/assemble.py):
;   0  forever       -- never returns; the picture stays until reset
;   1  until a key   -- jsr GETIN until a key is pressed, then fall through
;   2  WAITSECS secs  -- count KERNAL jiffies (JIFFYPS per second), then fall through
;   3  key OR secs   -- whichever comes first (keys still work, but it auto-
;                       advances after WAITSECS); used by the slideshow viewer
; On fall-through the caller restores the text screen and RTSes to BASIC.
; The KERNAL IRQ is left running by these viewers, so GETIN and the jiffy clock
; ($a0-$a2, big-endian, $a2 = least significant) both work.

cv_t0 = $fb                       ; 16-bit jiffy snapshot (free after the copy)
cv_el = $fd                       ; 16-bit elapsed jiffies

#if WAITMODE == 0
cv_wait:
        jmp cv_wait
#endif

#if WAITMODE == 1
        lda #$00
        sta $c6                   ; empty the keyboard buffer first, so a key left
                                  ; over from RUN doesn't dismiss the picture at once
cv_wait:
        jsr $ffe4                 ; GETIN
        beq cv_wait
#endif

#if WAITMODE == 2
        lda $a2
        sta cv_t0
        lda $a1
        sta cv_t0+1
cv_wait:
        sec
        lda $a2
        sbc cv_t0
        sta cv_el
        lda $a1
        sbc cv_t0+1
        sta cv_el+1
        lda cv_el+1
        cmp #>(WAITSECS*JIFFYPS)
        bcc cv_wait
        bne cv_done
        lda cv_el
        cmp #<(WAITSECS*JIFFYPS)
        bcc cv_wait
cv_done:
#endif

#if WAITMODE == 3
        lda #$00
        sta $c6                   ; empty the keyboard buffer first
        lda $a2
        sta cv_t0
        lda $a1
        sta cv_t0+1
cv_wait:
        jsr $ffe4                 ; GETIN -- any key ends the slide immediately
        bne cv_done
        sec                       ; else check the elapsed-jiffies timeout
        lda $a2
        sbc cv_t0
        sta cv_el
        lda $a1
        sbc cv_t0+1
        sta cv_el+1
        lda cv_el+1
        cmp #>(WAITSECS*JIFFYPS)
        bcc cv_wait
        bne cv_done
        lda cv_el
        cmp #<(WAITSECS*JIFFYPS)
        bcc cv_wait
cv_done:
#endif