[Coco] Assembly Help

Johann Klasek johann+coco at klasek.at
Wed Sep 3 14:27:02 EDT 2014


On Wed, Sep 03, 2014 at 12:33:01PM +0200, Tormod Volden wrote:
> On Wed, Sep 3, 2014 at 4:54 AM, Chad H wrote:
[..]
> >
> >                 LDD        ,X++                       GET BLOCK LENGTH(D)
> >
> >                 LDY         ,X++                       GET BLOCK START
> > ADDRESS(Y)
> >
> > XFER      LDA        ,X+                         GET SOURCE BYTE(A) FROM X
> >
> >                 STA        ,Y+                          PUT BYTE(A) AT Y
> >
> >                 DECD                                     MOVED BLOCK?

Is DECD a common shortcut for SUBD #$0001?

> Register D is a combination of registers A and B. So if you load A,
> you will overwrite the D value. Use for instance U for your counter.

As we all know with LEAU -1,U (or DECU !? according to the writing from above ;) )


Johann




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