meta New language targeting 2600

[Kaj de Vos]

I am developing a new language that I have been introducing here:

 

After the Atari 8-bit, I am now targeting it at the 2600. I just posted the first demo here:

Here is the source code:

 

unsafe!!! constant reference volatile byte! [
    ; TIA

    VSYNC= ~0000
    VBLANK
    WSYNC
    COLUBK= ~0009
    PF0= ~000D
    PF1
    PF2
    GRP0= ~001B
    GRP1
    ENAM0
    ENAM1
    ENABL
]

vertical-sync-bit= %0000'0010

VBLANK:  ; Set beam to on to use the entire vertical-blank overscan area
    ENABL:  ; Ball off
    ENAM1: ENAM0:  ; Missiles off
    GRP1: GRP0:  ; Players off
    PF2: PF1: PF0: 0  ; Playfield off; we only use the background

byte! [jiffies colour]

forever [
    VSYNC: WSYNC: vertical-sync-bit  ; Wait for end of scanline, then start vertical sync

    ; Vertical sync pulse.
    ; This lasts 3 scanlines, where some small work can be done to set up the next screen.

    colour: jiffies  ; Begin colour gradient, shifted by jiffy counter

    ; Wait three scanlines, then end vertical sync, continue vertical blank
    VSYNC: WSYNC: WSYNC: WSYNC: 0

    ; Vertical blank area, followed by the visible display area,
    ; followed by another vertical-blank overscan area.
    ; PAL and SECAM officially have 45 + 228 + 36 scanlines here, NTSC has 37 + 192 + 30.
    ; We generate 283 scanlines (plus the 3 for vertical sync), for a display frequency of 55Hz,
    ; inbetween PAL/SECAM and NTSC. It will work on all, if you have a tolerant television set.

    ; The first scanline is used for the setup overhead of the LOOP,
    ; so it gets the last colour wrapped over from the last scanline of the previous screen.
    ; Being the first line of the vertical blank overscan area, it is normally not visible.

    loop 282 [COLUBK: WSYNC: overflow increment colour]  ; Increment background colour for every scanline

    overflow increment jiffies
]

Here are some artifacts of the compilation. The assembler listing:

https://language.meta.frl/examples/platforms/Atari/2600/rainbow.list

A VICE labels file, for debuggers:
https://language.meta.frl/examples/platforms/Atari/2600/rainbow.labels

The memory sections map:
https://language.meta.frl/examples/platforms/Atari/2600/rainbow.map

 

It's my second 2600 program; please be gentle. ?

 

The language will be cross-platform on as many systems as possible. 2600 programs are developed by cross-compiling. In many cases, it is also needed to pre-compute data for a 2600 program. You will be able to write such tools in the same language, on your PC or Mac or other favourite system.

 

Edited December 10, 2021 by Kaj de Vos
Added screenshot

[Kaj de Vos]

Rainbow assembly

 

The language has an integrated assembler, so we could also write Rainbow like this:

 

https://language.meta.frl/examples/platforms/Atari/2600/rainbow-assembly.rom
https://language.meta.frl/examples/platforms/Atari/2600/rainbow-assembly.list
https://language.meta.frl/examples/platforms/Atari/2600/rainbow-assembly.labels
https://language.meta.frl/examples/platforms/Atari/2600/rainbow-assembly.map

 

 

unsafe!!! [
    constant reference volatile byte! [
        ; TIA

        VSYNC= ~0000
        VBLANK
        WSYNC
        COLUBK= ~0009
        PF0= ~000D
        PF1
        PF2
        GRP0= ~001B
        GRP1
        ENAM0
        ENAM1
        ENABL
    ]

    vertical-sync-bit= %0000'0010

    LDA 0
    STA PF0     ; Turn playfield off; we only use the background
    STA PF1
    STA PF2
    STA GRP0    ; Players off
    STA GRP1
    STA ENAM0   ; Missiles off
    STA ENAM1
    STA ENABL   ; Ball off
    STA VBLANK  ; Set beam to on to use the entire vertical-blank overscan area

    byte! jiffies

    forever:
        STA WSYNC  ; Wait for end of scanline
        LDA vertical-sync-bit  ; Start vertical sync
        STA VSYNC

        ; Vertical sync pulse.
        ; This lasts 3 scanlines, where some small work can be done to set up the next screen.

        LDX jiffies  ; Begin colour gradient, shifted by jiffy counter

        ; Wait three scanlines
        STA WSYNC
        STA WSYNC
        STA WSYNC
        ; End vertical sync, continue vertical blank
        LDA 0
        STA VSYNC

        ; Vertical blank area, followed by the visible display area,
        ; followed by another vertical-blank overscan area.
        ; PAL and SECAM officially have 45 + 228 + 36 scanlines here, NTSC has 37 + 192 + 30.
        ; We generate 283 scanlines (plus the 3 for vertical sync), for a display frequency of 55Hz,
        ; inbetween PAL/SECAM and NTSC. It will work on all, if you have a tolerant television set.

        TAY  ; A is still 0

        loop-256:
            INX  ; Increment colour for every scanline
            STA WSYNC
            STX COLUBK  ; Colour background
        DEY
        BNE loop-256

        LDY 26

        loop-26:
            INX
            STA WSYNC
            STX COLUBK
        DEY
        BNE loop-26

        INC jiffies  ; Count display frames
    JMP forever
]

 

More efficient code can be written this way, but it's clearly more elaborate than the high-level language.

[Kaj de Vos]

To keep this the main thread, here is the announcement I just made in the parent forum: