Re: A86: Re: i need an equate here
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Re: A86: Re: i need an equate here
That is essentially the routine from the ROM. I pretty much copied it from
the VTI debugger with ROM version 1.3. Clem probably meant that calling
that routine would set the checksum and turn of the calc _safely_, but I
have no idea.
> This is the same as the routine I found at $0E0B. Kirk says it is
> really at $0DFB. Maybe due to different ROM vers? I have 1.3. I was
> about to post the routine for anyone who wanted it, but it looks like
> once again Mr. Phillips beat me to it :) There IS a reference in the
> call table, it's just a little indirect of a way to get to it, and it
> unfortunately also turns the calc off. Clem has it titled
> '_setChecksum', at $4101, which I could have sworn was called '_off' or
> '_calcOff' or some such thing. I remember that number because I used to
> have lots of fun typing in CD0141 on a friend's calc and amazing them
> cause they thought I was turning off the calc through BASIC... although
> occasionally I used CD0941 when I didn't like the person :)
>
> Anyway, I put that routine in Lockdown, and now it doesn't reset the
> calc when you pull the batteries to charge them! It's about time!
>
> Cassady Roop
>
>
> David Phillips wrote:
> >
> > CalcChecksum:
> > ld a,$42
> > out (6),a
> > ld ix,$8000
> > ld bc,$3fff
> > ld hl,8
> > ld d,8
> > CalcChecksumLoop:
> > ld e,(ix)
> > inc ix
> > add hl,de
> > dec bc
> > ld a,b
> > or c
> > jr nz,CalcChecksumLoop
> > ld e,d
> > ex de,hl
> > sbc hl,de
> > ld (_onChecksum),hl
> > ret
> >
> > >
> > > Does anyone have an equate for ROM call $0E0B ? Better yet, anyone
know
> > > of a reference to this from the page 0D call table, so it is
compatible
> > > across versions?
> > >
> > > It calculates the _onChecksum value and stores it to HL.
>
>
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