mirror of
https://github.com/imjasonh/nescript
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ba23f8578a
An end-to-end FIPS 180-4 SHA-256 hasher running entirely on the NES.
The player types up to 16 ASCII characters on a 5x8 on-screen
keyboard, presses Enter, and the program computes and displays the
64-character hex digest.
Layout (`examples/sha256/*.ne`):
constants.ne layout + K[64] / H_INIT[8] tables
(declared as `var` with init_array because the
v0.1 compiler treats `const u8[N] = [...]` as
a no-op — noted in the file)
assets.ne 44-tile Tileset (A..Z, 0..9, punctuation,
special keys, cursor) shared between BG and
sprite layers
background.ne static nametable (title, labels, keyboard
grid) painted at reset
state.ne globals
sha_core.ne 32-bit byte primitives (copy, xor, and, add,
not, rotr, shr) in inline asm + sigma/Sigma
mixers + schedule/round steps + fold
render.ne OAM helpers for cursor, input buffer, and
64-nibble digest
keyboard.ne key dispatch table
entering_state.ne cursor navigation + typing + auto-demo
computing_state.ne phased driver (48 schedule steps + 64 rounds
+ fold across ~30 frames at 4 iterations each)
showing_state.ne renders the 256-bit digest as 8 rows of 8
sprite glyphs
Implementation notes:
- All 32-bit words live as 4 little-endian bytes in `wk[64]`,
`w[256]`, `h_state[32]` so every primitive walks four bytes with
`LDA {arr},X`/`STA {arr},X` chains and, for adds, a carry chain.
- Every primitive reads its parameters straight out of the
transport slots `$04`/`$05` rather than `{dst}`/`{src}`
substitutions: the inline-asm resolver looks parameters up in
the analyzer's allocation table but the codegen spills them to a
different per-function RAM slot, so `{dst}` would resolve to a
ZP slot nothing ever writes to. Bypassing the substitution
entirely sidesteps the issue without a compiler change.
- Rotate-right by any amount is a byte-rotate loop plus a bit-
rotate loop so the 10 SHA amounts (2, 6, 7, 11, 13, 17, 18, 19,
22, 25) all compile to a handful of chained `ROR`s.
- The headless jsnes golden auto-types "NES" after 1 s of idle and
captures its SHA-256 digest
AE9145DB5CABC41FE34B54E34AF8881F462362EA20FD8F861B26532FFBB84E0D
— byte-identical to `shasum` / `hashlib.sha256(b"NES")`.
Build: `cargo run --release -- build examples/sha256.ne`
https://claude.ai/code/session_01FRmSBruVWCufm3LsUVMs8v
86 lines
9 KiB
Markdown
86 lines
9 KiB
Markdown
# NEScript Examples
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## Quick Start
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```bash
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# Build the compiler
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cargo build --release
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# Compile all examples
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for f in examples/*.ne; do cargo run -- build "$f"; done
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# Or compile one
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cargo run -- build examples/hello_sprite.ne
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```
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Open any `.nes` file in an NES emulator ([Mesen](https://www.mesen.ca/), [FCEUX](https://fceux.com/), etc.)
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## Examples
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| File | Features | Description |
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|------|----------|-------------|
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| `hello_sprite.ne` | input, draw | Move a sprite with the d-pad |
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| `bouncing_ball.ne` | if/else, variables | Auto-bouncing sprite with edge detection |
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| `coin_cavern.ne` | states, functions, constants | 3-state game with gravity and coin collection |
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| `arrays_and_functions.ne` | arrays, functions, while | Enemy array with collision detection |
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| `state_machine.ne` | on enter/exit, transitions | Multi-state flow with timers |
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| `sprites_and_palettes.ne` | sprites, scroll, cast | Inline CHR data, PPU scroll writes, type casting |
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| `mmc1_banked.ne` | MMC1, banks, multiply | Banked mapper with software multiply |
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| `uxrom_user_banked.ne` | UxROM, `bank Foo { fun ... }`, cross-bank trampoline | First example to put real user code inside a switchable bank. The animation step lives in `bank Extras` and is invoked from the fixed-bank state handler via a generated `__tramp_step_animation` stub that selects bank 0, JSRs the body, then restores the fixed bank before returning. |
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| `uxrom_banked_to_banked.ne` | UxROM, banked → banked cross-bank call | Two `bank Foo { fun ... }` blocks: `step` lives in bank Logic and calls `clamp` in bank Helpers. The trampoline uses `ZP_BANK_CURRENT + PHA/PLA` to save and restore the caller's bank, so the same per-callee stub works whether the caller is in the fixed bank or another switchable bank. |
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| `palette_and_background.ne` | palette, background, set_palette, load_background | Reset-time initial load plus vblank-safe runtime swaps |
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| `auto_chr_background.ne` | `background @nametable(...)` with auto-CHR | First example to use the `@nametable("file.png")` shortcut without supplying any matching CHR data. The resolver dedupes the PNG's 8×8 cells, encodes them via the same brightness-bucketing the sprite CHR encoder uses, and slots them into CHR ROM at the next free tile slot. The committed `auto_chr_bg.png` is a 256×240 grayscale gradient that exercises ~50 unique tiles. |
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| `friendly_assets.ne` | named colours, grouped palette, pixel art, tilemap+legend, palette_map, scalar sfx pitch, note-name music | Exercises every "friendlier" asset syntax at once — the `palette` uses `bg0..sp3` + a shared `universal:`, the sprite is authored as ASCII pixel art, the background uses a `legend { ... } + map:` tilemap with a `palette_map:` for attributes, the sfx uses a scalar `pitch:` + `envelope:` alias, and the music uses note names (`C4, E4 40, rest 10`) with a `tempo:` default. |
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| `noise_triangle_sfx.ne` | `channel: noise`, `channel: triangle` on `sfx` blocks | Demonstrates the noise and triangle sfx channels. Declares one noise burst and one triangle bass note, plays each on a timer so the emulator harness captures both the pixel output and the APU state. |
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| `sfx_pitch_envelope.ne` | varying-pitch pulse SFX | A 16-frame frequency sweep written as a per-frame `pitch:` array on a Pulse-1 sfx. The compiler emits a separate `__sfx_pitch_<name>` blob and gates the audio tick's pitch update path on the `__sfx_pitch_used` marker, so programs that stick to the scalar `pitch:` form still get byte-identical ROM output. |
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| `metasprite_demo.ne` | declarative multi-tile sprites | A 16×16 hero sprite split into a `metasprite Hero { sprite: Hero16, dx: [...], dy: [...], frame: [...] }` declaration. `draw Hero at: (px, py)` then expands to one `DrawSprite` op per tile in the IR lowering, each with its dx/dy added to the user's anchor point and the frame offset by the underlying sprite's base tile. The codegen needs no metasprite-specific support — it sees N regular draws and the OAM cursor allocator handles the slots. |
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| `nested_structs.ne` | nested struct fields, array struct fields, chained literals | Two `Hero` instances each carry a `Vec2` position and a `u8[4]` inventory. Exercises `hero.pos.x` chained access, `hero.inv[i]` array-field access, and chained struct-literal initializers (`Hero { pos: Vec2 { x: ..., y: ... }, inv: [...] }`). |
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| `platformer.ne` | **every subsystem** | End-to-end side-scrolling demo: custom CHR tileset, full 32×30 nametable with per-region attribute palettes, 2×2 metasprite hero with gravity/jump physics, wrap-around horizontal scrolling, stomp-or-die enemy collisions with a live stomp-count HUD, coin pickups, user-declared SFX + music, and a Title → Playing → GameOver state machine with a proximity-based autopilot so the headless harness cycles through stomp, stomp, die, and retry inside six seconds. Regenerate the tile art with `cargo run --bin gen_platformer_tiles`. |
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| `sprite_flicker_demo.ne` | `cycle_sprites`, 8-per-scanline hardware limit | Twelve sprites packed onto the same 4-pixel band — two more than the NES's 8-sprites-per-scanline hardware budget. The W0109 analyzer warning fires at compile time, and a `cycle_sprites` call at the end of `on frame` rotates the OAM DMA offset one slot per frame so the PPU drops a *different* sprite each frame. The permanent-dropout failure mode becomes visible flicker, which the eye reconstructs across frames. The classic NES technique used by Gradius, Battletoads, and every shmup that ever existed. |
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| `war.ne` | **production-quality card game**, multi-file source layout | A complete port of the card game War, split across `examples/war/*.ne` files and pulled in via `include` directives. Title screen with a 0/1/2-player menu (cursor sprite, blinking PRESS A, brisk 4/4 march on pulse 2), a 50-frame deal animation, a deep `Playing` state with an inner phase machine (`P_WAIT_A`/`P_FLY_A`/.../`P_WAR_BANNER`/`P_WAR_BURY`/`P_CHECK`), card-conserving queue-based decks built on a 200-iteration random-swap shuffle, a "WAR!" tie-break that buries 3+1 face-down cards per player and plays a noise-channel thump per bury, and a victory screen with the builtin fanfare. The first NEScript example to use a top-level file as a thin shell that `include`s ~12 component files; building it surfaced seven compiler bugs across the analyzer, IR lowerer, and codegen that were all fixed on the same branch (see `git log` for details). |
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| `pong.ne` | **production-quality Pong**, powerups, multi-ball, multi-file | A complete Pong game split across `examples/pong/*.ne`. CPU VS CPU / 1 PLAYER / 2 PLAYERS title menu with brisk pulse-2 title march and autopilot, smooth ball physics with wall and paddle bouncing, CPU AI that tracks the ball with a reaction lag and dead zone, three powerup types (LONG paddle for 5 hits, FAST ball on next hit, MULTI-ball on next hit spawning 3 balls) that bounce around the field and are caught by paddle AABB overlap, multi-ball scoring (each ball scores a point, round continues until last ball exits), inner phase machine (`P_SERVE`/`P_PLAY`/`P_POINT`), and a "PLAYER N WINS" victory screen with the builtin fanfare. First-to-7 wins. |
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| `sha256.ne` | **interactive SHA-256**, inline-asm 32-bit primitives, multi-file | A full FIPS 180-4 SHA-256 hasher split across `examples/sha256/*.ne`. An on-screen 5×8 keyboard grid lets the player type up to 16 ASCII characters (`A`..`Z`, `0`..`9`, space, `.`, backspace, enter), and pressing ↵ runs the 48-entry message-schedule expansion + 64-round compression on the NES itself. Every 32-bit primitive (`copy`, `xor`, `and`, `add`, `not`, rotate-right, shift-right) is hand-tuned inline assembly that walks the four little-endian bytes of a word with `LDA {wk},X` / `ADC {wk},Y` chains, so a whole round costs a few thousand cycles. The phased driver runs four schedule steps or four rounds per frame so the full compression finishes well under a second, and the 64-character hex digest renders as sprites in 8 rows of 8 glyphs at the bottom of the screen. The jsnes golden auto-types `"NES"` after 1 s of keyboard idle and captures its hash `AE9145DB5CABC41FE34B54E34AF8881F462362EA20FD8F861B26532FFBB84E0D`. |
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## Emulator Controls
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| NES Button | Typical Key |
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|------------|-------------|
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| D-pad | Arrow keys |
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| A | Z |
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| B | X |
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| Start | Enter |
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| Select | Right Shift |
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## About Sprites
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Sprite names in `draw Player at: (x, y)` are parsed and recorded in the AST.
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You can define sprites with inline CHR tile data:
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```
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sprite Player {
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chr: [0x3C, 0x42, 0x81, 0x81, 0x81, 0x81, 0x42, 0x3C,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
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}
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```
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If no matching sprite declaration exists, the draw uses the built-in default
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tile (a smiley face). See `sprites_and_palettes.ne` for a full example.
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## Compiler Commands
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```bash
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# Compile to ROM
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cargo run -- build game.ne
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# Custom output path
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cargo run -- build game.ne --output my_game.nes
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# Type-check only
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cargo run -- check game.ne
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# View generated 6502 assembly
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cargo run -- build game.ne --asm-dump
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# Debug mode
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cargo run -- build game.ne --debug
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```
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