A89: Need help with buggy code

To: assembly-89@lists.ticalc.org
Subject: A89: Need help with buggy code
From: BLoWh0Le@aol.com
Date: Tue, 4 May 1999 22:38:44 EDT
Delivered-To: assembly-89-outgoing@towerguard.unix.edu.sollentuna.se
Delivered-To: assembly-89@lists.ticalc.org
Reply-To: assembly-89@lists.ticalc.org

Attached is my latest attempt at a game.  What I am trying to do right now is 
create a routine to read a level map.  My level map looks something like this:

level1:
dc.b 0,0,0,0,0,0,0,0,0,0,0,0,0,0
dc.b 0,1,0,1,0,1,0,1,0,1,0,1,0,0
dc.......
.......

If there is a 1, my program "should" draw a block on the screen according to 
where the 1 is in the map.  My problem is that I suck at programming and 
can't figure out what is wrong with my code.  Whenever I run it (in VTI68k), 
it displays a few blocks in seemingly random locations and even displays part 
of the TI-89's graphing screen.  If anyone can take a look at my code and 
find what's wrong (besides sloppy coding), I would appreciate it a lot.  
Thanks guys.

    include "tios.h"
    include "util.h"
    include "graphlib.h"

    xdef _main
    xdef _comment
    xdef _ti89


;***********************************MAIN
_main:

ini_vars:
    move.l  #0,currentlvl
    bsr     ini_level

prog_loop:
    
    jsr     util::idle_loop
    rts

;***********************************INITIALIZE EACH LEVEL
ini_level:
    jsr     graphlib::clr_scr

    move.l  #level1,a0
    move.l  currentlvl,d0
    mulu.w  #126,d0
    add.l   d0,a0
    move.l  a0,levelptr

    move.w  #0,var1
ini_level_loop1:
    move.w  #0,var2
ini_level_loop2:
    move.l  #levelptr,a0
    move.w  var1,d1
    move.w  var2,d0
    move.w  #14,d2
    bsr     look_up

    cmp.b   #1,d0
    bne     no_block
    move.w  var1,d1
    move.w  var2,d0
    mulu.w  #8,d1
    mulu.w  #8,d0
    move.l  #sprite_block,a0
    jsr     graphlib::put_sprite

no_block:
    add.w   #1,var1
    cmp.w   #9,var1
    bne     ini_level_loop2

    add.w   #1,var2
    cmp.w   #14,var2
    bne     ini_level_loop1

    rts

look_up:                ;d0=column
    add.w   d0,a0       ;d1=row
    mulu.w  d2,d1       ;d2=row width
    add.w   d1,a0       ;a0=pointer
    move.b  (a0),d0
    rts

level1:
    dc.b 0,0,0,0,0,0,0,0,0,0,0,0,0,0
    dc.b 0,1,0,1,0,1,0,1,0,1,0,1,0,0
    dc.b 0,0,0,0,0,0,0,0,0,0,0,0,0,0
    dc.b 0,1,0,1,0,1,0,1,0,1,0,1,0,0
    dc.b 0,0,0,0,0,0,0,0,0,0,0,0,0,0
    dc.b 0,1,0,1,0,1,0,1,0,1,0,1,0,0
    dc.b 0,0,0,0,0,0,0,0,0,0,0,0,0,0
    dc.b 0,1,0,1,0,1,0,1,0,1,0,1,0,0
    dc.b 0,0,0,0,0,0,0,0,0,0,0,0,0,0

sprite_block:
    dc.w 8
    dc.w 1
    dc.b %01111110
    dc.b %10000001
    dc.b %10111001
    dc.b %10100001
    dc.b %10100001
    dc.b %10000001
    dc.b %10000001
    dc.b %01111110
mask_block:
    dc.b %11111111
    dc.b %11111111
    dc.b %11111111
    dc.b %11111111
    dc.b %11111111
    dc.b %11111111
    dc.b %11111111
    dc.b %11111111

currentlvl      dc.l 0
levelptr        dc.l 0

var1            dc.w 0
var2            dc.w 0

_comment        dc.b "bricks",0

    end