Octo Chip8 Program

readme.txt

Play this game by pasting the program into http://johnearnest.github.io/Octo/

options.json

{"tickrate":7,"fillColor":"#FFCC00","backgroundColor":"#996600","buzzColor":"#FFAA00","quietColor":"#000000","shiftQuirks":false,"loadStoreQuirks":false}

prog.ch8

: smile
    0b00100100
    0b00100100
    0b00000000
    0b10000001
    0b01000010
    0b00111100

: body
    v2 := 0
    loop
        v0 := random 0b01111111
        v1 := random 0b00111111
        sprite v0 v1 6
        v2 += 1
        if v2 != 32 then
    again
    clear
;

: main
    # uncomment for SuperChip high resolution mode:
    hires
    i := smile
    loop
        draw-board
	v0 := key
    again

:alias piecex vA
:alias piecey vB
:alias piece  vC

: draw-board
  piecex := 0
  piecey := 0

  clear
  loop
    # v1 = piecey * 8
    v1 <<= piecey
    v1 <<= v1
    v1 <<= v1

    # piece := board[piecex + 8*piecey]
    i := board
    i += piecex
    i += v1
    load v0
    piece := v0

    if piece == 0 then jump next-pos

    i := white-sprites

    # check if black
    v0 <<= piece
    if vF == 1 then i := black-sprites

    # i := (white/black)-sprites[piece_number * 8]
    # note that v0 already is piece_number * 2
    v0 <<= v0
    v0 <<= v0
    i += v0

    # v2 = 32 + piecex * 8
    v2 <<= piecex
    v2 <<= v2
    v2 <<= v2
    v2 += 32

    # now, v1 = piecey * 8 and v2 = 32 + piecex * 8. draw sprite!
    sprite v2 v1 8

    : next-pos
    piecex += 1
    if piecex == 8 then piecey += 1
    if piecex == 8 then piecex := 0
    if piecey != 8 then
      again
;


# piece is:
# 000S0PPP, where S is 0/1 for white/black, and P 

: board
  0x82 0x83 0x84 0x85 0x86 0x84 0x83 0x82
  0x81 0x81 0x81 0x81 0x81 0x81 0x81 0x81
  0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
  0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
  0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
  0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
  0x01 0x01 0x01 0x01 0x01 0x01 0x01 0x01

: white-sprites  # HACK: need white-sprites to be 8 bytes before the pawn
  0x02 0x03 0x04 0x05 0x06 0x04 0x03 0x02

: white-pawn   0x38 0x44 0x44 0x28 0x44 0x82 0xfe 0x00
: white-rook   0xaa 0xd6 0x82 0x44 0x44 0x82 0xfe 0x00
: white-knight 0x14 0x68 0x94 0xc4 0x22 0x42 0xfe 0x00
: white-bishop 0x7c 0x92 0xba 0x92 0x54 0x82 0xfe 0x00
: white-queen  0xaa 0xaa 0xaa 0x7c 0x44 0x82 0xfe 0x00

: black-sprites
: white-king   0x10 0x38 0x92 0xee 0x44 0x82 0xfe 0x00

: black-pawn   0x38 0x7c 0x7c 0x38 0x7c 0xfe 0xfe 0x00
: black-rook   0xaa 0xfe 0xfe 0x7c 0x7c 0xfe 0xfe 0x00
: black-knight 0x14 0xe8 0xf8 0x38 0x7c 0xfe 0xfe 0x00
: black-bishop 0x7c 0xee 0xc6 0xee 0x6c 0xfe 0xfe 0x00
: black-queen  0xaa 0xaa 0xaa 0x7c 0x7c 0xfe 0xfe 0x00
: black-king   0x10 0x38 0x92 0xfe 0x7c 0xfe 0xfe 0x00