It's a compiled language. The compiler takes source code and spits out CA65-compatible assembly. The compiler does very little work though. Most of the implementation is just CA65 macros and subroutines.
Because the output is CA65 assembly, it is very easy to mix with hand-written assembly code. You can reference assembly labels in NORTH code, and also reference NORTH labels in assembly code. It's easy to write games that mix and match the two languages.
Anyway, here's a quick top-level overview:
- All values are 16 bit.
- Values are stored in a stack, stored in RAM. This can be up to 512 bytes, or less.
- The X register is used to index into the stack.
- The hardware stack at $100 is used to store return addresses.
- 2 bytes of zeropage are needed for storing temporary variables.
Code: Select all
+=: [ over load + store ] -=: [ over load minus store ] umax: [ over over u< 'swap when drop ] umin: [ over over u> 'swap when drop ] smax: [ over over s< 'swap when drop ] smin: [ over over s> 'swap when drop ] negative?: [0 s<] abs: [dup negative? [0 minus] when] friction: [dup abs 2 u<= [drop 0] [dup negative? [2 +] [2 -] if] if] movePlayer: [ 'player_x player_xspeed.load buttons_held.loadLo 'BUTTON_LEFT & [4 -] when buttons_held.loadLo 'BUTTON_RIGHT & [4 +] when buttons_held.loadLo 'friction unless 512 smin -512 smax player_xspeed.copy += 'player_y player_yspeed.load buttons_held.loadLo 'BUTTON_UP & [4 -] when buttons_held.loadLo 'BUTTON_DOWN & [4 +] when buttons_held.loadLo 'friction unless 512 smin -512 smax player_yspeed.copy += ] drawPlayerSprite: [ player_y.load (240<<8) umin (OAM+0).storeHi 0 (OAM+1).storeLo 0 (OAM+2).storeLo player_x.load (OAM+3).storeHi ] init: [ 0 player_xspeed.store 0 player_yspeed.store (128<<8) player_x.store (128<<8) player_y.store ] mainLoop: [ movePlayer drawPlayerSprite ]
You'll need a Haskell compiler.
Maybe I'll write documentation if people are interested.