A89: Oops, here's the file

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A89: Oops, here's the file

here

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

    xdef _main

    xdef _comment

    xdef _ti89

_main:

    move.w   #2,-(a7)               ; use font #2 (large font)
    jsr      tios::FontSetSys       ; set the font
    add.l    #2,a7                  ; clean up the stack

    bsr     while                   ; begin program loop
    rts

while:
    add.w   #1,count                ; add one to cycle counter
    cmp     #200,count              ; if counter = 200 then
    beq     end_while               ; goto end_while

    bsr     change_dir              ; goto change_dir
    bsr     move_ball               ; goto move_ball

    bsr     while                   ; repeat program loop
    rts

end_while:
    rts

move_ball:
    cmp     #1,xdir
    beq     move_right
    cmp     #2,xdir
    beq     move_left
    cmp     #1,ydir
    beq     move_down
    cmp     #2,ydir
    beq     move_up
    rts
move_right:
    add.w   #1,xpos
    rts
move_left:
    sub.w   #1,xpos
    rts
move_down:
    add.w   #1,ypos
    rts
move_up:
    sub.w   #1,ypos
    rts

change_dir:
    cmp     #0,xpos
    beq     change_right
    cmp     #140,xpos
    beq     change_left
    cmp     #0,ypos
    beq     change_down
    cmp     #50,ypos
    beq     change_up
    rts
change_right:
    move.w  #1,xdir
    rts
change_left:
    move.w  #2,xdir
    rts
change_down:
    move.w  #1,ydir
    rts
change_up:
    move.w  #2,ydir
    rts

;    jsr      util::idle_loop        ; library routine which waits until a key

delay:
    move.w  #0,D7
    bsr     delay_loop
    rts
delay_loop:
    add.w   #1,D7
    cmp     delay_len,D7
    beq     delay_end
    bsr     delay_loop
    rts
delay_end:
    rts

drawstuff:
    jsr      util::clr_scr          ; clear the screen
    move.w   #4,-(a7)               ; move the first param to the stack
    lea      string(pc),a0          ; move adress of string to the stack
    move.l   a0,-(a7)
    move.w   ypos,-(a7)               ; push position for y pos
    move.w   xpos,-(a7)               ; push position for x pos
    jsr      tios::DrawStrXY        ; call the DrawStrXY ROM function
    add.l    #10,a7                 ; restore the stack pointer
    rts

string          dc.b "O",0
xpos            dc.w 74
ypos            dc.w 25
xdir            dc.w 1,0
ydir            dc.w 1,0
count           dc.w 0
delay_len       dc.w 700

_comment    dc.b "Bouncing Ball",0

    end