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From: gerardo@island.seas.ucla.edu (Gerardo Chaves)
Newsgroups: comp.sys.apple2
Subject: Re: One Byte Memory Reads
Message-ID: <983@lee.SEAS.UCLA.EDU>
Date: 23 Aug 90 02:07:29 GMT
References: <900808130731.2020095d@CCC.NERSC.GOV>
Sender: news@SEAS.UCLA.EDU
Organization: SEASnet, University of California, Los Angeles
Lines: 46

In article <900808130731.2020095d@CCC.NERSC.GOV> MORAGUES%CCV.MFENET@CCC.NERSC.GOV writes:

<.... stuff deleted>

>  
>I was wondering if there is a way to make the GS only do an 8-bit reference
>while in native mode.  I would appreciate sample code in TML pascal if 
>possible, ORCA Assembler or Pascal would also be appreciated.  I don't have
>the exact memory locations with me now, but if you want them, I can post it.
>
>Thanks in advance for your help
>
>Bob Moragues
>MORAGUES@CCC.NERSC.GOV

I'm not sure if this is what you need, but here is some source code in
TML Pascal II, (should work with v 1.5 as well) that does just an 
8 bit read in order to find out if the a button on the paddles has
been pressed (the locations belong to the game port I believe)..:

function butn(n:integer):boolean; {PROCEDURE TO CHECK FOR BUTTONS/APPLE KEYS}
var p:ptr;
 i:integer;
 begin
  butn:=false;
  if (n>-1) and (n<4) then begin 
   case n of
     0:p:=pointer($C061);
     1:p:=pointer($C062);
     2:p:=pointer($C063);
     3:p:=pointer($C060);
    end;

	i:=p^[1]; {this assignment alone does the access to only 8 bits}

	if (i<0) then butn:=true;
	 end;
  end;


Hopefully this will work for you. Vince Cooper helped me with that  p^[1] deal.


	Gerardo Chaves
	Programmer, U.C.L.A. Intervention Program 
	gerardo@island.seas.ucla.edu