First public commit.

lenser/c128/viewer/slideshow.s

@@ -0,0 +1,211 @@
+; Commodore 128 VDC (8563) slideshow viewer -- 640x200 high-colour mode.
+;
+; Steps through NIMAGES VDC images named "00".."NN" on the disk, each a 16K VDC
+; RAM image (codes/attributes/font, the same body the single hicolor/mono viewer
+; copies).  For each slide it KERNAL-loads the file into RAM bank 0 at $4000,
+; copies the 16K verbatim into the VDC's own RAM, sets the global background
+; (R26) from the per-image ss_fgbg table, then waits (key / seconds / both)
+; before advancing.  Boots via RUN"PIC" -> the BASIC stub SYSes here.
+;
+; #defines from the build wrapper --
+;   WAITMODE  1 key / 2 seconds / 3 both        WAITSECS  timeout seconds
+;   JIFFYPS   50 PAL / 60 NTSC                   NIMAGES   image count
+;   LOOPFLAG  1 wrap at end, 0 stop
+; ss_fgbg (one byte per image, VDC R26 background) is appended by the wrapper.
+
+        * = $1C20
+
+src  = $fb
+adlo = $fd
+adhi = $fe
+cntl = $02
+cnth = $03
+
+start:
+        lda #$0e
+        sta $ff00               ; KERNAL + I/O + RAM $4000-$BFFF all visible
+        lda #$00
+        sta $9d                 ; suppress KERNAL LOAD messages
+        sta ssidx
+
+mainloop:
+        jsr namebuild
+
+        ; ---- C128 LOAD "NN",8,1 into RAM bank 0 at $4000 ----
+        lda #$00
+        ldx #$00
+        jsr $ff68               ; SETBNK (load bank 0, name bank 0)
+        lda #2
+        ldx #<ssname
+        ldy #>ssname
+        jsr $ffbd               ; SETNAM
+        lda #1
+        ldx #8
+        ldy #1
+        jsr $ffba               ; SETLFS (secondary 1 = file's own address)
+        lda #0
+        jsr $ffd5               ; LOAD
+
+        ; ---- copy 16384 bytes from $4000 -> VDC $0000 ----
+        lda #$00
+        sta src
+        lda #$40
+        sta src+1
+        lda #$00
+        sta adlo
+        sta adhi
+        sta cntl
+        lda #$40
+        sta cnth
+        jsr copyblk
+
+        ; ---- per-image global background (R26) + cursor off (R10) ----
+        ldx ssidx
+        lda ss_fgbg,x
+        ldx #26
+        jsr vdcw
+        ldx #10
+        lda #$20
+        jsr vdcw
+
+        ; ---- wait for the slide's dwell ----
+        jsr ss_wait
+
+        ; ---- advance ----
+        inc ssidx
+        lda ssidx
+        cmp #NIMAGES
+        bcc mainloop
+#if LOOPFLAG == 1
+        lda #$00
+        sta ssidx
+        jmp mainloop
+#else
+        rts
+#endif
+
+; --------------------------------------------------------------------------- ;
+; wait -- key / seconds / both, KERNAL GETIN + jiffy clock ($a0-$a2, $a2 = LSB)
+; (reuses $fb-$fe as 16-bit scratch now the copy is done)
+cv_t0 = $fb
+cv_el = $fd
+
+ss_wait:
+#if WAITMODE == 1
+ss_drain:
+        jsr $ffe4
+        bne ss_drain            ; flush leftover keys
+ss_k:
+        jsr $ffe4
+        beq ss_k
+        rts
+#endif
+#if WAITMODE == 2
+        lda $a2
+        sta cv_t0
+        lda $a1
+        sta cv_t0+1
+ss_s:
+        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 ss_s
+        bne ss_sd
+        lda cv_el
+        cmp #<(WAITSECS*JIFFYPS)
+        bcc ss_s
+ss_sd:
+        rts
+#endif
+#if WAITMODE == 3
+ss_drain:
+        jsr $ffe4
+        bne ss_drain
+        lda $a2
+        sta cv_t0
+        lda $a1
+        sta cv_t0+1
+ss_b:
+        jsr $ffe4
+        bne ss_bd               ; any key ends the slide
+        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 ss_b
+        bne ss_bd
+        lda cv_el
+        cmp #<(WAITSECS*JIFFYPS)
+        bcc ss_b
+ss_bd:
+        rts
+#endif
+
+; build the 2-char filename "NN" (PETSCII) from ssidx (0..99)
+namebuild:
+        lda ssidx
+        ldx #$2f
+        sec
+nb_ten:
+        inx
+        sbc #10
+        bcs nb_ten
+        adc #10
+        ora #$30
+        sta ssname+1
+        txa
+        sta ssname
+        rts
+
+; copy cnth/cntl bytes from (src) to VDC RAM starting at adhi/adlo
+copyblk:
+        ldx #18
+        lda adhi
+        jsr vdcw
+        ldx #19
+        lda adlo
+        jsr vdcw
+        ldx #31
+        ldy #$00
+        lda (src),y
+        jsr vdcw
+        inc src
+        bne cb1
+        inc src+1
+cb1:
+        inc adlo
+        bne cb2
+        inc adhi
+cb2:
+        lda cntl
+        bne cb3
+        dec cnth
+cb3:
+        dec cntl
+        lda cntl
+        ora cnth
+        bne copyblk
+        rts
+
+vdcw:
+        stx $d600
+vw:
+        bit $d600
+        bpl vw
+        sta $d601
+        rts
+
+ssidx:  .byte 0
+ssname: .byte $30,$30
+; ss_fgbg table (one byte per image) appended by the build wrapper