working on a little programming language for the gameboy. this is an early code example (very much subject to change etc etc)

tenprint.inchl

[ 10 print implementation in an experimental stack-based language for
  the gameboy ]

!section tenprint rom0

!staticvar @seed wram0

^inchl_entrypoint
    $ab &seed put    
    jp &tenprint

@waitvblank
    $44 geff
    144 diff
    jpnz &waitvblank
    ret

@rand [ from https://foobles.neocities.org/blog/2024-06-06/prng ]
    &seed get double
    jpnc :skip_xor

    $46 xor $ec add
    jp :done

    .skip_xor $eb add
    .done dup &seed put

    ret

@tenprint

    $00 $40 puff [ turn off lcd so we can access vram ]

    [ draw / to tile data ]
    $00 .loop
        %11 over lshift over double $88 put
        %10 over lshift over double inc $88 put
        inc dup $08 diff
        jpnz :loop
    drop

    [ draw \ to tile data ]
    $00 .loop2
        %11000000 over rshift over double $10 add $88 put
        %10000000 over rshift over double inc $10 add $88 put
        inc dup $08 diff
        jpnz :loop2
    drop

    %10010001 $40 puff [ turn the lcd on again ]
    %11100100 $47 puff [ set palette ]

    [ populate the tilemap ]
    .forever
        #9800 { dup2 #9A40 eq2 blnot } { 
            dup2 $0 { dup 20 lt } { 
                call &waitvblank
                dup push
                over2 rotl add21
                call &rand %1 and $80 add rotr put
                pop inc 
            } while
            drop drop drop
            $20 add21
        } while
    jp :forever


    halt

tenprint_v2.inchl

[ 10 print implementation in an experimental stack-based language for
  the gameboy ]

!section tenprint rom0

!staticvar @seed wram0

^inchl_entrypoint
    $ab &seed put12    
    jp &tenprint

@waitvblank
    $44 geff 144 diff
    jpnz &waitvblank
    ret

@rand [ adapted from https://foobles.neocities.org/blog/2024-06-06/prng ]
    &seed get double jpnc :skip_xor
    $46 xor $ec add jp :done
    .skip_xor $eb add
    .done dup &seed put12
    ret

@tenprint

    $00 $40 puff [ turn off lcd so we can access vram ]

    [ draw / to tile data ]
    $00 .loop
        %11 over lshift over double $88 put12
        %10 over lshift over double inc $88 put12
        inc dup $08 diff
        jpnz :loop
    drop

    [ draw \ to tile data ]
    $00 .loop2
        %11000000 over rshift over double $10 add $88 put12
        %10000000 over rshift over double inc $10 add $88 put12
        inc dup $08 diff
        jpnz :loop2
    drop

    %10010001 $40 puff [ turn the lcd on again ]
    %11100100 $47 puff [ set palette ]
    %00010000 $00 puff [ read buttons ]

    [ populate the tile map ]
    .forever #9800 { 

        call &waitvblank

        [ set palette based on keys ]
        $00 geff %1 and { %11100100 $47 puff } { %00011011 $47 puff } ifte

        [ draw a row ]
        $0 {
            *add21 call &rand %1 and $80 add waitvram put21
            inc dup 20 lt
        } while drop

        $20 add21
        dup2 #9A40 ne2

    } while drop2 jp :forever 

    halt