[Coco] Extended basic 1.1 command?

[Bill Pierce]

Harry, I just ripped the code straight from a program in Rainbow. There were lots of other subs so I imagine the method of entry had to do with part of the other code for joysticks, hi-res interface, screen print (pmode4) and others so modifying the code here would be totally up to you and your needs. I didn't even look at the code for acuracy as I used this very code for several programs over the years and it never failed me. If you see mods for better code then be my guest. :-)

Bill P

Music from the Tandy/Radio Shack Color Computer 2 & 3
https://sites.google.com/site/dabarnstudio/
Bill Pierce
ooogalapasooo at aol.com




-----Original Message-----
From: Harry Hurst <hhos at st-tel.net>
To: coco <coco at maltedmedia.com>
Sent: Wed, Nov 21, 2012 8:59 am
Subject: Re: [Coco] Extended basic 1.1 command?


If I understand this, then:

Entry conditions
A : 0 = Right  1 = Left   2 = both
U : Pointer to array with button data at BDWN offset

Exit conditions
Button condition in BDWN,U and B register
A, B and X are trampled

Is this right? If so, then why not eliminate the INCB at line 9200 and
enter with
A : 1 = Right  2 = Left  3 = both  ?

HH

> 08500 *THIS DOES A BUTTON READ OFF THE RIGHT/LEFT JOYSTICK
> 08600 BUTSTA   PSHS      A                           SAVE RIGHT/LEFT FLAG
> 08700                         LDX          #$FF00             POINT TO THE
> I/O PORT
> 08800                         LDA          2,X                       GET
> THE KEY SELECT DATA
> 08900                         LDB          #$FF         SELECT NO KEYS
> 09000                         STB          2,X                       TO
> READ JUST THE BUTTONS
> 09100                         PULS    B                            GET
> RIGHT/LEFT BUTTON SELECT
> 09200                         INCB
> MAKE IT "01"(R) OR "10" (L)
> 09300                         COMB
> MAKE SELECTED BIT ZERO
> 09400                         ORB     ,X                IS GET THAT BUTTON
> BIT
> 09500                         STA      2,X                        RESTORE
> KEY SELECT DATA
> 09600                         COMB
> MAKE IT A ONE IF PRESS
> 09700                         ANDB      #3                         ONLY
> RIGHT/LEFT BUTTON BITS!
> 09800                         STB       BDWN,U  UPDATE BUTTON DOWN STATUS
> 09900                         RTS
> AND EXIT
>




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