Re: 80 Columns under cc65?

["John B. Matthews" <nospam@nospam.com>]

In article <g4cog9$q9e$1@online.de>, ol.sc@web.de (Oliver Schmidt) 
wrote:

> >> How do I get an 80-column text mode on an Apple 2 under cc65?
> 
> >It looks like the cc65 conio library goes to some lengths to avoid 
> >changing whatever your program loader sets.
> 
> That's very true. And in fact it goes beyond that: In contrast to at
> least some other cc65 targets the Apple2 conio implementation allows
> you to mix stdio and conio. Additionally you can use the well-known
> Apple2 zero-page variables to restrict the output to a certain window
> both for stdio and conio.

Oliver: thanks for expanding on this. I'm still new to cc65:-)

> >          LDA MACHID
> >          AND #2
> >          BEQ NO80COL
> >          JSR $C300
> 
> I've tried recently to do that from within a cc65 program via inline
> assembler but that mixed up something with ProDOS so file I/O didn't
> work anymore. I'll have to investigate but my current work life
> situation doesn't allow for that. So the current workaround is to set
> 80-column mode before starting the cc65 program.

Oliver: the code above was from a ProDOS system program. A non-system 
cc65 program launched from the Basic prompt under ProDOS is running 
alongside BASIC.SYSTEM. It might be necessary to update the BASIC Global 
Page Default I/O vectors after initializing the card:

BE30:  VECTOUT   DW  COUT1       ;Current character output routine
BE32:  VECTIN    DW  CHIN1       ;Current character input routine

I'll have to learn enough inline assembler to try it myself, but 
experimenting from the Basic prompt seems to confirm this. I'm tempted 
to just try printing control-DPR#3.

Interestingly, not updating the vectors appears to turn on trace!

]mtr
*c300g
*^c
]10 ?"Hello"
]run
#10 Hello

ProDOS is also disconnected, but call 976 ($3d0) restores normalcy.

-- 
John B. Matthews
trashgod at gmail dot com
home dot woh dot rr dot com slash jbmatthews