Re: LZ: Prog help

Subject: Re: LZ: Prog help
From: Ben Shakal <shakal@ns.net>
Date: Sun, 23 Sep 1996 21:07:46 +0000
In-Reply-To: <LZ: Prog help>

There are several things I noticed about your program:


   > After some suggestions i revised the program now i just get my exiting message 
   > printed and the calc freezes...
   > 
   > Here is the new one... :
   > 
   > #include "ti-85.h"
   > .org 0
   > .db "By Frank Apap",0
   > 
   > Init:
   >  ld a,4
   >  out (5),a
   >  ROM_CALL(CLEARLCD)
   >  ld b,40                   ; x start
   >  ld c,30                   ; y start
   > 
   > Start:
   >     call GET_KEY   ; get a key
   >     cp $04         ; up ?
   >      jr nz,nextkey
   >     CALL_Z(up)
   >      JUMP_(Start)


The two zero checks in a row are repetitive.  If you are going 
to do it this way, you should make it simply CALL_(up), but I don't 
think this should affect the execution of the program.  A better way 
might be to just do a jr z,up.  I.E.:
  call GET_KEY
  cp $04
  jr z,up
  cp $01
  jr z,down
   ...


Then at the end of the up handling routine just do a jr or JUMP_ back 
to Start.  It will result in a much shorter program.  If you do 
decide to use the first method, you will also need to...
 
   > nextkey:
   >     cp $01         ; down
   >     CALL_Z(down)


...repeat the jr nz,nextkey except this time use a different name 
(i.e. nextkey2 or checkdown).  There may be some other problems 
preventing your program from running but these are the one(s) I
noticed.  Also, like Eric said before, you might want to take a look 
at ZTeach2 on ticalc.org.


Hope this helps!


Ben
shakal@ns.net

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