Hey Gang,

"Ullrich von Bassewitz" <uz@remove-to-reply.musoftware.de> schrieb im
Newsbeitrag news:3io45b.qaf.ln@news.musoftware.de...
> Axel Muhr <axelAtgeekdotDotcom> wrote:
> > Chris (Morse)? Adam? Any ideas, hints? Thanks in advance...
>
> The apple libraries don't have an implementation for the clock() function,
and
> therefore no CLK_TCK constant.

What a thread! This grew huge since I had my last look ;-)

Ok, in the meantime I've discussed a bit with Ulrich about several
solutions... My first idea was VBL (like others suggested here, too), but my
suggestion

@ticka:  bit $c019 ; Loop VBL low
              bpl ticka

@tickb:  bit $c019 ; Loop VBL high
              bmi tickb ; ein Tickcycle ist durch
<inc counter here>

was rightfully "killed" by Ullrich, as it just counts while running (i.e. no
background-counting). So my next idea was a interupt handler (coping with
II,IIe,IIc and IIgs)... for googles sake, I found this old code from David
Empson, which could be a basis to work from. What do you think?

Cheers, Axel

* VBL interrupt handler for the IIe, IIc and IIgs, for use from
* Applesoft BASIC.  (untested at the time of posting)
*
* by David Empson (dempson@actrix.gen.nz)
*
* This program is hereby donated to the public domain.  If you distribute
* it, please include the full text of the relevant portion of the original
* article.

        jmp install      ; Entry point to install the handler
        jmp remove       ; Entry point to remove the handler

mouseCN dfb $00          ; Modified to hold mouse slot in $Cn format
mouseN0 dfb $00          ; Modified to hold mouse slot in $n0 format
vblcount dfb $00         ; Incremented for each VBL

* Routine to do the installation steps

install

* Locate the mouse.

        lda #$C7         ; Start the search at slot 7
        sta $3D
        lda #$00
        sta $3C          ; Set up a pointer for the slot search
        sta mouseCN      ; Ensure our important variables are cleared
        sta vblcount
slotlp  ldx #4           ; Set up count for lookup table
bytelp  lda offsets,X    ; Get offset into card
        tay
        lda ($3C),Y      ; Get a byte from the card
        cmp values,X     ; Does it match?
        bne notmouse     ; If not, this slot isn't a mouse
        dex
        bpl bytelp       ; Loop back around for next byte
        lda $3D
        sta mouseCN      ; Store the slot number in $Cn format
        tax              ; and save it in X
        asl
        asl
        asl
        asl
        sta mouseN0      ; Store the slot number in $n0 format
        bne gotmouse     ; Branch is always taken
notmouse
        ldx $3D
        dex
        stx $3D
        cpx #$C1         ; Done all slots yet?
        bcs slotlp       ; Loop for the next slot
nomouse rts              ; Return to BASIC

* We have found the mouse.  Set up our interrupt handler.

gotmouse

        ldy #$13
        lda ($3C),Y      ; Get the location of the SERVEMOUSE routine
        sta doservm+1    ; Patch the call into the interrupt handler
        stx doservm+2
        iny
        lda ($3C),Y      ; Get the location of the READMOUSE routine
        sta doreadm+1    ; Patch the call into the interrupt handler
        stx doreadm+2

* Set up the mouse firmware.

        ldy #$19
        lda ($3C),Y      ; Get the location of the INITMOUSE routine
        sta doinitm+1
        stx doinitm+2    ; Patch our call
        ldy #$12
        lda ($3C),Y      ; Get the location of the SETMOUSE routine
        sta dosetm+1
        stx dosetm+2     ; Patch our call
        ldy mouseN0
doinitm jsr $0000        ; Patched with location of INITMOUSE

* Install the interrupt handler.

        jsr $BF00        ; Call ProDOS
        dfb $40          ; ALLOC_INTERRUPT call
        da  allocpb      ; Address of parameter block
        bcs nomouse      ; If error, forget about it

* Set up the appropriate mouse mode.

        lda #$09         ; Mode: enable mouse, VBL interrupt only

* Fall through to our setmouse subroutine.  It will return to BASIC.

setmouse

* Subroutine to set the mouse mode to the value in A.

        ldx mouseCN
        ldy mouseC0
dosetm  jsr $0000        ; Patched with location of SETMOUSE
        rts              ; Return to BASIC or caller

* Routine to disable and remove the interrupt handler.

remove

* Check that the install routine has been called successfully.

        ldx mouseCN
        beq noremove

* Disable the mouse