[Coco] 6809 CC Reg Overflow bit

[Brendan Donahe]

Ok, dumb followup question then - if those 100s and 200s are decimal (I see
no $) then why is this an overflow?  Is overflow for a signed byte?

Brendan

On Tue, Nov 6, 2018 at 4:48 PM William Astle <lost at l-w.ca> wrote:

> On 2018-11-06 3:14 p.m., Salvador Garcia via Coco wrote:
> > Hi all. I am reading William Barden's Assembly Language for the Color
> Computer and on the bottom of page 57 he presents the following code
> <snipped>:
> >
> > LDA #100
> > ADDA #100   100 + 100 = 200  = V!
> >
> > Then on the second paragraph below the code he states:
> >
> >
> > "... The first ADD added an immediate 100 to the 100 in the A register
> for a result of 200. This is an overflow condition, and the V Condition
> Code should have been set to a 0, indicating no overflow:"
> >
> > If the V Condition Code is set to a 1 to indicate overflow, and the 100
> + 100 op caused an overflow, why is he saying that the V Condition code is
> set to a 0?
> >
> > Am I missing something? As always, thanks! Salvador
>
> The text is in error. V will be set after that instruction sequence.
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco
>