Re: A86: I need help...

To: assembly-86@lists.ticalc.org
Subject: Re: A86: I need help...
From: Jeanne9005@aol.com
Date: Sat, 11 Dec 1999 13:25:17 EST
Reply-To: assembly-86@lists.ticalc.org


In a message dated Sat, 11 Dec 1999 12:32:14 PM Eastern Standard Time, "Chris Remo"  writes:

> 
> I am an absolute newbie asm programmer in every way, and I have written a
> simple program so I can try to understand loops...  It's supposed to display
> string: five times, but it doesn't really work...  Could someone offer any
> advice?  Thanks
> 
> 
> 
> 
> #include "ti86asm.inc"
> #include "asm86.h"
> 
> .org _asm_exec_ram
> 
>  nop
>  jp ProgStart
>  .dw 0
>  .dw ShellTitle
> 
> ShellTitle:
>  .db "Chris Remo's Program",0
> 
> ProgStart:
> 
> _homeup EQU 4A95h       ; 0 to curCol and 0 to curRow
> 
>  call _clrLCD       ; clears screen
> 
>  call _homeup       ; 0 to curCol and 0 to curRow
>  ld b,5         ; puts 5 in b register
>  ld a,0

you can change the above line of code to sub a or xor a, always 0

> subby_loop:         ; my awesome loop
>  dec b         ; decrements b
>  inc a         ; increments a
>  ld (_curRow),a       ; loads value of b into curRow
>  ld (_curCol),0       ; loads value of b into curCol
>  ld hl,string       ; puts string in hl
>  call _puts        ; displays string
>  call _getkey

the _getkey is unneeded, unless you want the user to be able to exit

>  jr nz,subby_loop      ; continued until b is zero

you can also change this to djnz subby_loop.  djnz means Decrement, Jump if Not Zero.  It uses reg. b, which also means you can take out the dec b statement above.


>  ret          ; return to shell or homescreen
>  ret

only one ret is necessary here...

> 
> string:
>  .db "SHOULD show 5 times",0    ; creates string, terminated with 0
> 
> 
> 
> .end