;loops stored at 0x3000
;score stored at 0x3001
;ship texture stored at 0x3002
;astroid texture stored at 0x3003
;sleepCounter is stored at 0x3004

:start
     set [0x9000], 0
     set a, 0
     set b, 0
     set x, 0
     set y, 0
     set z, 0
     set i, 0
     set j, 0
     set c, 0x80E0
     set [0x3002], 0xF03E
     set [c], [0x3002]
     set [0x3000], 1
     set [0x3001], 0
     set [0x3003], 0xf007
     set [0x3004], 0xffff
     set pc, drawbar

:sleep
     sub [0x3004], 1
     set PC, loop_1

:loop_1
     ifn [0x3004], 0
         set PC, sleep
     set a, [0x3000]
     add a, 1
     set [0x3000], a
     mod a, 0x04FF ;scoreAddTimeout
     ife a, 0x0000
         set PC, addscore
:loop_1_2
     add [0x3000], 1
     set a, [0x3000]
     mod a, 0x00FF ;movetimeout
     ife a, 1
         set PC, loop_2
     set PC, loop_5
:loop_2
     set x, 31
     add x, 0x8000
:loop_3
     add x, 1
     ife [x], [0x3003]
         set PC, moveAstroid
:loop_4
     ifn x, 0x8200
         set PC, loop_3
:loop_5
     set a, [0x9000]
     set [0x9000], 0x0000
     ife a, 0x0001
         set PC, left
     ife a, 0x0004
         set PC, down
     ife a, 0x0002
         set PC, right
     ife a, 0x0003
         set PC, up
:loop_6
     set a, [0x3000]
     mod a, 0x00FF ;placetimeou
     ife a, 0
         set PC, placeAstroid
     set PC, loop_1

:moveAstroid
     set [x], 0x0000
     set y, x
     sub x, 1
     ife [x], [0x3002]
         set PC, crash
     sub y, 0x800
     mod y, 32
     ife y, 0
         set PC, loop_4
     set [x], [0x3003]
     set PC, loop_4

:addscore
     add [0x3001], 1
     set PC, drawScore
     set PC, loop_1_2

:left
     set x, c
     sub x, 0x800
     mod x, 32
     ife x, 0
         set PC, loop_6
     set [c], 0x0000
     sub c, 1
     ife [c], [0x3003]
         set PC, crash
     set [c], [0x3002]
     set PC, loop_6

:right
     set x, c
     sub x, 0x800
     mod x, 32
     ife x, 31
         set PC, loop_6
     set [c], 0x0000
     add c, 1
     ife [c], [0x3003]
         set PC, crash
     set [c], [0x3002]
     set PC, loop_6

:up
     ifg 0x8040, c
         set PC, loop_6
     set [c], 0x0000
     sub c, 32
     ife [c], [0x3003]
         set PC, crash
     set [c], [0x3002]
     set PC, loop_6

:down
     ifg c, 0x81BF
         set PC, loop_6
     set [c], 0x0000
     add c, 32
     ife [c], [0x3003]
         set PC, crash
     set [c], [0x3002]
     set PC, loop_6

:drawbar
     set x, 0x8000
     set y, 0x8000
     add y, 480
     set z, 61
     bor z, 0xf001
:drawbarloop
     set [y], z
     set [x], z
     add x, 1
     add y, 1
     ifn x, 0x8020
         set PC, drawbarloop
     set x, 0
     set y, 0
     set z, 0
     set PC, drawScoreText

:placeAstroid
     set a, [seed]
     mul a, 0x1235
     add a, 1
     add a, c
     div a, 4
     set [seed], a
     mul a, 7
     mul a, 17
     add a, 0x72da
     mod a, 14
     add a, 2
     mul a, 32
     add a, 0x8000
     sub a, 1
     add [seed], 0x03FA
     mod [seed], a
     ;div [seed], 2
     set [a], [0x3003]
     set PC, loop_1

:seed dat 0x02ba

:drawScoreText
    ife (scoreText+a), 0
        set PC, loop_1
    set b, (scoreText+a)
    add a, 0x8000
    bor b, 0xf000
    set [a], b
    sub a, 0x8000
    add a, 1
    set PC, drawScoreText

:drawScore
    set b, 0x800c
    set x, [0x3001]
:drawScore2
    set a,x
    and a,15
    ifg a,9
        add a,7
    add a,0x30
    bor a,0xf000
    set [b],a
    sub b,1
    shr x,4
    ifn x,0
        set PC, drawScore2
    set PC, loop_1_2

:clear
    set a, 0x8000
    set b, 0
    set c, 0
:clearLoop
    set [a], 0
    add a, 1
    ife a, 0x8200
        set PC, start
    set PC, clearLoop

:crash
    set [x], 0xf02a
    set b, 0
    set PC, drawGameOver1

:crashloop
    ifn [0x9000], 0
        set PC, clear
    set PC, crashloop

:drawGameOver1
    set b, 0x80AA
    set c, 0
:drawGameOverLoop1
    set a, (gameOverText+c)
     ife a, 0
        set PC, drawGameOver2
    bor a, 0xf000
    add c, 1
    set [b], a
    add b, 1
    set PC, drawGameOverLoop1

:drawGameOver2
    set b, 0x80CA
    set c, 0
:drawGameOverLoop2
    set a, (YouDiedText+c)
    ife a, 0
        set PC, drawGameOver3
    bor a, 0xf000
    add c, 1
    set [b], a
    add b, 1
    set PC, drawGameOverLoop2

:drawGameOver3
    set b, 0x80EA
    set c, 0
:drawGameOverLoop3
    set a, (scoreText+c)
    ife a, 0
        set PC, drawGameOver4
    bor a, 0xf000
    add c, 1
    set [b], a
    add b, 1
    set PC, drawGameOverLoop3

:drawGameOver4
    set b, 0x80EA
    add b, 32
    set c, 0
:drawGameOverLoop4
    set a, (PressAnyKeyText+c)
    ife a, 0
        set PC, drawScoreAtGameOver
    bor a, 0xf000
    add c, 1
    set [b], a
    add b, 1
    set PC, drawGameOverLoop4

:drawScoreAtGameOver
    set b, 0x80EA
    add b, 12
    set x, [0x3001]
    set [0x9000], 0
:drawScoreAtGameOver2
    set a,x
    and a,15
    ifg a,9
        add a,7
    add a,0x30
    bor a,0xf000
    set [b],a
    sub b,1
    shr x,4
    ifn x,0
        set PC, drawScoreAtGameOver2
    set PC, crashloop

:scoreText
    dat "SCORE: 0x0000",0
:gameOverText
    dat "GAME OVER",0
:YouDiedText
    dat "YOU DIED",0
:PressAnyKeyText
    dat "Press any key",0