[Coco] Bug in VCC ???

[Luis Antoniosi (CoCoDemus)]

This seems to be the same problem with CoCoFPGA. The fix will make it work
for both.



On Wed, Apr 16, 2014 at 2:35 PM, Bill Pierce <ooogalapasooo at aol.com> wrote:

>
> It runs on my Coco 3 so it must be bugged to run bugs... The actuall Coco
> was always forgiving of us "buggy" programmers... We got away with a lot
> that wouldn't fly on any other machine :-)
>
> Still playing Zork 1.... Nice job!
> Post the link when ya get it fixed and I'll overclock Vcc so it won't be
> sooo slow in responding....
>
>
> Bill Pierce
> "Today is a good day... I woke up" - Ritchie Havens
>
>
> My Music from the Tandy/Radio Shack Color Computer 2 & 3
> https://sites.google.com/site/dabarnstudio/
> Co-Webmaster of The TRS-80 Color Computer Archive
> http://www.colorcomputerarchive.com/
> Co-Contributor, Co-Editor for CocoPedia
> http://www.cocopedia.com/wiki/index.php/Main_Page
> E-Mail: ooogalapasooo at aol.com
>
>
>
>
> -----Original Message-----
> From: Luis Antoniosi (CoCoDemus) <retrocanada76 at gmail.com>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Wed, Apr 16, 2014 2:24 pm
> Subject: Re: [Coco] Bug in VCC ???
>
>
> Ok, found the culprit. The VCC seems to be fine.
>
>             andb    ~(NF|HF)
>
> should be:
>
>             andb    #~(NF|HF)
>
> my bad :/
>
> and maybe MESS has a bug in the half carry.
>
>
>
>
> On Wed, Apr 16, 2014 at 1:57 PM, William Astle <lost at l-w.ca> wrote:
>
> > On 14-04-16 11:46 AM, Luis Antoniosi (CoCoDemus) wrote:
> >
> >> I found VCC does Half-Carry different from 6809.
> >>
> >> doing this:
> >>
> >> ldd #$0fc9
> >> addb #$40
> >> adca #$00
> >>
> >> it will set the HC on VCC but not on 6809.
> >>
> >>
> > I would have expected the 6809 to actually set H in this case. The
> > references I have available say it should. After all, you do have a carry
> > from bit 3 to bit 4 during the ADCA.
> >
> > Still, the H flag is only used by DAA. I would be surprised if it is the
> > problem in this case (unless the code that's failing is using DAA
> somehow?)
> >
> > --
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> >
>
>
>
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