mirror of
https://github.com/imjasonh/nescript
synced 2026-07-08 08:55:38 +00:00
The audio subsystem was a sketch: `play name` / `start_music name` /
`stop_music` parsed, lowered, and emitted a few hardcoded register
writes from a builtin name table. No user-declared effects, no
per-frame envelope, no note streams, no real engine.
This flesh-out brings audio up to the quality bar of the rest of
the compiler (sprites, palettes, bank switching, scanline IRQ,
etc.) with a full data-driven pipeline:
## Asset pipeline (new `src/assets/audio.rs`)
- `sfx Name { duty, pitch, volume }` blocks compile into per-frame
pulse-1 envelopes. Pitch/volume arrays must match in length; each
entry is one NMI's worth of `$4000` data.
- `music Name { duty, volume, repeat, notes }` blocks compile into
flat `(pitch, duration)` streams for pulse 2. Pitch 0 is a rest,
1-60 indexes a builtin period table covering C1-B5.
- `resolve_sfx` / `resolve_music` walk the program for `play` /
`start_music` references and append builtin fallbacks for any
name that isn't user-declared — so `play coin` still works
without a `sfx Coin { ... }` block.
- Builtin effects (coin, jump, hit, click, cancel, shoot, step)
and tracks (theme, battle, victory, gameover) synthesize through
the same compile path as user decls — one data model, one driver.
## Runtime engine (`src/runtime/mod.rs`)
- `gen_audio_tick()` walks both channels every NMI: reads one
envelope byte through `(ZP_SFX_PTR),Y` -> writes `$4000`,
advances ptr, mutes on zero sentinel. Music decrements the note
counter, advances to the next `(pitch, dur)` pair on zero, looks
up the period through `(__period_table),Y`, loops on `0xFF 0xFF`.
- `gen_period_table()` emits a 60-entry equal-tempered table
(A4 = 440 Hz, NTSC 1.789773 MHz CPU clock) with length-counter
load bits pre-baked into each high byte.
- `gen_data_block()` emits a label + raw-bytes pseudo pair so
user sfx/music data can be spliced into PRG with regular labels
that the two-pass assembler resolves.
- New ZP layout: `$05/$06` music loop base, `$07` music state
(duty/volume/loop/active), `$0C-$0F` sfx and music pointers.
## IR codegen (`src/codegen/ir_codegen.rs`)
- `with_audio(sfx, music)` registers compile-time trigger constants
per blob name.
- `gen_play_sfx` emits: write period to `$4002`/`$4003`, load
envelope pointer into `ZP_SFX_PTR` via SymbolLo/SymbolHi of
`__sfx_<name>`, mark the sfx counter active.
- `gen_start_music` stamps the header byte into `ZP_MUSIC_STATE`
with the active bit OR'd in, seeds both ptr and loop base from
`__music_<name>`, primes the duration counter.
- `gen_stop_music` mutes pulse 2 and clears state.
## Linker (`src/linker/mod.rs`)
- New `link_with_all_assets(user_code, sprites, sfx, music)` path
that splices driver body, period table, and each sfx/music data
blob into PRG — all guarded on the `__audio_used` marker so
silent programs pay zero ROM cost.
## Assembler (`src/asm/opcodes.rs`, `src/asm/mod.rs`)
- New `AddressingMode::Bytes(Vec<u8>)` variant for raw-data
pseudo-instructions. `NOP+Bytes(v)` emits the payload verbatim,
letting the linker splice ROM data tables into a code section
and still have `Label` / `SymbolLo` / `SymbolHi` fixups resolve
correctly in the same assembly pass.
## Analyzer
- `play` / `start_music` now validate the name against user decls
and builtin tables. Unknown names emit E0505 with a helpful list
of builtins — previously a typo would silently compile to no-op.
## Parser
- New `sfx_decl` / `music_decl` grammar with property-style
configuration. Strict validation: duty 0-3, volume 0-15, pitch
arrays must match volume length, music notes must come in pairs,
pitch 0-60, duration ≥ 1.
## Tests
+170 new tests across every layer:
- `src/assets/audio.rs`: 17 tests (compile, resolve, builtins,
shadowing, label sanitation, nested reference walks)
- `src/parser/tests.rs`: 13 tests (valid/invalid sfx + music
declarations, property validation, play/start_music/stop_music)
- `src/analyzer/tests.rs`: 7 tests (builtin acceptance, user decl
acceptance, unknown-name rejection)
- `src/runtime/tests.rs`: 10 tests (audio tick labels, RTS end,
$4000 write, $4004 mute, period table assembly, A4 = 440 Hz,
length counter bits, data block verbatim emit)
- `src/linker/tests.rs`: 4 tests (sfx/music blob placement,
pointer resolution, elision when unused)
- `src/codegen/ir_codegen.rs`: rewrote the 4 existing audio tests
to match the new data-driven contract
- `tests/integration_test.rs`: 4 end-to-end tests including a
user-declared `sfx` + `music` program that verifies bytes land
in PRG ROM at the right addresses
## Docs
- New Audio section in `docs/language-guide.md` with syntax
reference, builtin tables, and an explanation of how the
driver works at compile and run time.
- `docs/architecture.md` updated to reflect the real audio
pipeline instead of the old "audio import stubs" stub.
- `docs/future-work.md` moves audio from "status: minimal" to
"status: full subsystem" with a narrower list of follow-up work
(triangle/noise/DMC channels, NSF/FTM imports, richer envelopes).
- `examples/audio_demo.ne` rewritten to showcase user-declared
`sfx LongCoin`, `sfx Zap`, `music Theme`, still demonstrating
builtin fallback via `play coin`.
Total: 424 tests passing (381 unit + 43 integration), clippy clean,
fmt clean, all 19 examples compile.
https://claude.ai/code/session_015WfaDttE3DpWn9rpyfpQd8
|
||
|---|---|---|
| .. | ||
| arrays_and_functions.ne | ||
| audio_demo.ne | ||
| bitwise_ops.ne | ||
| bouncing_ball.ne | ||
| coin_cavern.ne | ||
| comparisons.ne | ||
| function_chain.ne | ||
| hello_sprite.ne | ||
| inline_asm_demo.ne | ||
| logic_ops.ne | ||
| loop_break_continue.ne | ||
| match_demo.ne | ||
| mmc1_banked.ne | ||
| mmc3_per_state_split.ne | ||
| README.md | ||
| scanline_split.ne | ||
| sprites_and_palettes.ne | ||
| state_machine.ne | ||
| structs_enums_for.ne | ||
| two_player.ne | ||
NEScript Examples
Quick Start
# Build the compiler
cargo build --release
# Compile all examples
for f in examples/*.ne; do cargo run -- build "$f"; done
# Or compile one
cargo run -- build examples/hello_sprite.ne
Open any .nes file in an NES emulator (Mesen, FCEUX, etc.)
Examples
| File | Features | Description |
|---|---|---|
hello_sprite.ne |
input, draw | Move a sprite with the d-pad |
bouncing_ball.ne |
if/else, variables | Auto-bouncing sprite with edge detection |
coin_cavern.ne |
states, functions, constants | 3-state game with gravity and coin collection |
arrays_and_functions.ne |
arrays, functions, while | Enemy array with collision detection |
state_machine.ne |
on enter/exit, transitions | Multi-state flow with timers |
sprites_and_palettes.ne |
sprites, palettes, scroll, cast | Inline CHR data, palette switching, type casting |
mmc1_banked.ne |
MMC1, banks, multiply | Banked mapper with software multiply |
Emulator Controls
| NES Button | Typical Key |
|---|---|
| D-pad | Arrow keys |
| A | Z |
| B | X |
| Start | Enter |
| Select | Right Shift |
About Sprites
Sprite names in draw Player at: (x, y) are parsed and recorded in the AST.
You can define sprites with inline CHR tile data:
sprite Player {
chr: [0x3C, 0x42, 0x81, 0x81, 0x81, 0x81, 0x42, 0x3C,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
}
If no matching sprite declaration exists, the draw uses the built-in default
tile (a smiley face). See sprites_and_palettes.ne for a full example.
Compiler Commands
# Compile to ROM
cargo run -- build game.ne
# Custom output path
cargo run -- build game.ne --output my_game.nes
# Type-check only
cargo run -- check game.ne
# View generated 6502 assembly
cargo run -- build game.ne --asm-dump
# Debug mode
cargo run -- build game.ne --debug