Brainfuck Tic Tac Toe - Hotseat Version (BFC syntax)

tictactoe.bfc

[
    BF Tic Tac Toe - Hotseat Version
    ================================
    
    Memory structure:
    00: mode, col, row, zflag, tmp
    04: flag, cell_A1, flag,  cell_A2, flag,  cell_A3,
    0A: flag, cell_B1, flag,  cell_B2, flag,  cell_B3,
    10: flag, cell_C1, flag,  cell_C2, flag,  cell_C3,
    
    Mode: (+1/"X", -1/"O")
    Cells: ASCII char (" ", "X", "O")
    Flags: (0, +1)
]
+ Set mode in (0)
6> set all cells to SPACE
20+>>20+>>20+>>
20+>>20+>>20+>>
20+>>20+>>20+>>
18< move back to mode
[ while mode is not zero
    >,31- read col
    >,31- read row
    >A-[A+,A-] continue reading until newline; drop
    <<[>3+<-]> calculate index in row
    [>3+<3-] move row to first flag
    >+ set zflag
    >>[[>>+<<-]-]+ set flag at cell(row)
    -[+<<-] return to zflag
    3< go to mode
    
    >+<
    +
    [>-<-- if flag positive; toggle
        3>+ set zflag
        >>-[+>>-] move to flagged cell
        >58+ set cell char
        <-[+<<-] return to zflag
        3<
    ]>[<+ if flag negative; toggle
        3>+ set zflag
        >>-[+>>-] move to flagged cell
        >4F+ set cell char
        <-[+<<-] return to zflag
        3<
    >]<
    
    TODO: check win conditions

    6> print board
    .>>.>>.>20+.[-]>
    .>>.>>.>20+.[-]>
    .>>.>>.>20+.[-]>
    19<
]