[Coco] 64k test

[Steve Strowbridge]

My 64K test is to run Sailor Man, the first commercial 64K game released
for the CoCo.
If that runs, the RAM is good.



Steve Strowbridge, aka
The Original Gamer Stevie Strow
Website/Merchandise/CoCo links page:
http://ogsteviestrow.com
Email:  ogsteviestrow at gmail.com
Get your "Game Play Goodnes" fix of CoCo and retro videos at:
http://youtube.com/ogsteviestrow


On Wed, Jul 19, 2017 at 5:08 AM, Ciaran Anscomb <cocomalt at 6809.org.uk>
wrote:

> Johann Klasek wrote:
> > On Mon, Jul 17, 2017 at 03:38:59AM +0000, Rietveld Rietveld wrote:
> > > This program will test for 64k memory on a Coco 1/2
> >
> > Thanks! Would you share the source assembly, too? Or would you provide
> > us a disassembly of it?
>
> Looks like it's a "copy ROM to RAM" routine really.
>
> Here's what I'm using:
>
> -----CUT-----
>                 ; test for 64K
>                 clr flag_64k
>                 sta reg_sam_tys
>                 lda $0062
>                 ldb $8063
>                 coma            ; a != [$0062]
>                 comb            ; b != [$8063]
>                 std $8062
>                 cmpd $8062
>                 bne no_64k      ; didn't write
>                 cmpd $0062
>                 beq no_64k      ; *did* shadow write
>                 com flag_64k
> no_64k          sta reg_sam_tyc
> -----CUT-----
>
> Where flag_64k is somewhere useful.
>
> Checks that a write to upper 32K in map type 1 succeeds, and that it
> *didn't* shadow write to the lower 32K.  Address chosen so that it
> *probably* doesn't destroy anything useful if it did shadow write.
>
> For my use I don't care, but if you need it, you'll want to make
> it preserve the original values in those locations and restore them
> afterwards.
>
> ..ciaran
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco
>