mirror of
https://github.com/imjasonh/nescript
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5 commits
| Author | SHA1 | Message | Date | |
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Claude
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0600f5b872
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codegen: fuse compare-then-branch to drop boolean materialization
Every NEScript condition (`if x < N`, `while i < end`, etc.) lowers in two IR ops: `CmpX(d, a, b)` materializes a 0/1 boolean into temp `d`, and the block's terminator `Branch(d, t, f)` reads `d` and branches on it. The codegen faithfully emitted both halves — `LDA / CMP / branch-to-true / LDA #0 / JMP done / true: LDA #1 / done:`, then later `LDA d_slot / BNE branch_t / JMP branch_f` — about 14 cycles + 13 bytes per condition. The 6502's natural pattern is one `CMP` + one branch on the flags it just set: 8 cycles, no register-clobber, no temp slot. Detect the canonical pattern in `gen_block` (last op is an 8-bit `CmpX` whose dest temp is what the terminator branches on, with no other uses) and emit the fused form directly via a new `gen_cmp_branch` helper. The temp's allocation, store, load, and the terminator's branch fall away. Bookkeeping subtlety: the source temps `a`/`b` must be retired *after* the fused emit, not before — the original `gen_op` order is "emit body of op, then `retire_op_sources`". Decrementing their use counts before the CMP would free their slots while they were still live; `load_temp(a)` would then re-allocate `a` to whatever stale slot the free list popped next. Got hit by this on the first attempt — the SHA-256 example dutifully returned all-zero hashes until the order was fixed. Updated `ir_codegen_local_label_suffix_is_bank_namespaced`: the test was relying on `if x == 0` to emit `__ir_cmp_*` labels for its bank-namespacing check, which the fusion now collapses into direct branches. Switched the test source to a shift-by-variable pattern (`x = x << n`), which always emits `__ir_shift_loop_*` labels regardless of future cmp/branch optimizations. Cycle savings: ~6 cycles per condition. The SHA-256 rotate loops alone account for ~9K cycles per block. Across all examples the cycle drift shows up as audio-tick phase shifts in five timing-sensitive ROMs (`audio_demo`, `friendly_assets`, `noise_triangle_sfx`, `platformer`, `sfx_pitch_envelope`); the goldens for those are refreshed in this commit, plus `platformer.gif` (the only demo gif whose bytes actually moved). Verified: cargo test/clippy/fmt clean on rustc 1.95.0; emulator harness 34/34; reproducibility diff clean; SHA-256 of "NES" still computes to AE9145DB…4E0D. https://claude.ai/code/session_01FRmSBruVWCufm3LsUVMs8v |
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Claude
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20a244b9e7
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examples: regenerate ROMs, gifs, and goldens after codegen local fix
Commit
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Claude
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169a481099
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feat(platformer): add stomp-or-die enemy collisions, live HUD, GameOver state
The previous platformer example drew enemies but had almost no interaction with them: only enemy 1 had a stomp check, the stomp window was unreachable under the default +1-px-per-frame-plus-a- jump-every-40-frames autopilot, contact from any other angle was a silent no-op, and the header comment promised a "title → playing → game-over state machine" that didn't actually exist. The README demo gif and the committed golden both froze that state — a level the player could walk through indefinitely with no consequence. Flesh the enemy interaction model out into something real: - `resolve_enemy_hit(e_sx)`: one helper, called symmetrically for both enemies. Computes the player/enemy hitbox overlap (horizontal in `e_sx ∈ (72, 96)`, vertical in `player_y ∈ (152, 176)`) and branches three ways — falling onto the head is a stomp bounce (`rise_count = 6`, `fall_vy = 0`, `stomp_count += 1`, `play Boing`); overlap while `rise_count > 0` is a grace pass-through so the stomp bounce itself can't retrigger contact on the same enemy; anything else (walking into the side, standing on the ground against the enemy) is fatal — `alive = 0` and `play hit`. - New `GameOver` state: draws four enemy tiles across the middle of the screen plus a coin row sized to `stomp_count`, stops the music, lingers 60 frames then auto-retries, and also honours Start for an instant retry. - Proximity-based autopilot: pre-jump when an enemy is exactly 19 px ahead (`e1_sx == 99` or `e2_sx == 99`), capped at two jumps per life by `auto_jumps < AUTOPILOT_JUMPS`. Tuning: a JUMP_RISE=12, GRAVITY_CAP=4 jump lands the player's feet at enemy-head height exactly 21 frames after lift-off, by which point the autopilot camera has scrolled the enemy under the player. The first jump fires on Playing frame 1 and stomps enemy 1 on frame 22; the second fires on Playing frame 101 and stomps enemy 2 on frame 122. After that the autopilot is exhausted and the third enemy encounter (camera wraps back past enemy 1) is fatal — the golden harness now sees the full stomp, stomp, die, retry, stomp loop instead of a frozen walk. - Live HUD: up to four coin sprites in the top-left, one per stomp, rendered both during `Playing` and on the `GameOver` screen so the score is visible in the death frame. `Playing`'s player draw is now guarded by `if alive == 1` so the hero disappears on the fatal-contact frame and the enemy that killed them is visible underneath. Verified with a per-frame ZP trace through the patched puppeteer + jsnes harness: first stomp at emu frame 44 (camera_x=22), second at emu frame 144 (camera_x=122), death at emu frame 283 (camera_x=5 after a 256-px wrap), `Playing` restart at emu frame 343, third stomp at emu frame 365. All 22 emulator goldens still match after the update, and `docs/platformer.gif` regenerated from the new ROM now shows two clean stomps, a clean side-collision death, the GameOver screen, and the retry cycle all inside the 6-second demo window. Golden updates: - `tests/emulator/goldens/platformer.png` — the frame-180 capture now shows the hero walking forward with a two-coin HUD after both autopilot stomps (previously: a frozen bouncing hero). - `tests/emulator/goldens/platformer.audio.hash` — the track now includes two `Boing` stomp bounces, which shifts the hash. - `examples/platformer.nes` — rebuilt from the rewritten source. Also updates the platformer rows in `README.md` and `examples/README.md` to match the new gameplay. https://claude.ai/code/session_013Bi4H4YQ5or5HtMB4doUFi |
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Claude
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5e3e68ca11
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docs: regenerate platformer.gif and lock it as a CI invariant
The optimizer fix in the previous commit changes the observable
gameplay of `examples/platformer.ne` — pre-fix the player got
spurious enemy-1 stomp bounces every time coin 2 drifted into its
pickup window, so the README demo gif showed the player bouncing
mid-air around emu frames 85-125 instead of walking through the
coin at ground level. Regenerate `docs/platformer.gif` from the
fixed compiler so the README matches reality.
To stop this from drifting again, treat the gif the same way the
repo already treats `examples/*.nes`:
- `gifenc` + `jsnes` + the harness are deterministic, so a fresh
recording byte-matches a valid commit. Verified across two
back-to-back runs (identical md5).
- `.github/workflows/ci.yml`'s `emulator` job now renders the gif
into `/tmp/platformer.gif` and `cmp`s it against `docs/platformer.gif`,
emitting a `::error` annotation pointing at the exact rerun
command if the committed copy is stale. This piggybacks on the
existing puppeteer + node setup, adding ~20s to the job.
- `scripts/pre-commit` runs the same check locally, but only when
`examples/platformer.{ne,nes}`, `tests/emulator/record_gif.mjs`,
or `tests/emulator/harness.html` is staged, and only if
`tests/emulator/node_modules` is already installed. Cold-start
puppeteer is ~20s — too slow to pay on every commit, but cheap
enough to pay when something gif-relevant changed.
- The header of `tests/emulator/record_gif.mjs` and the project
conventions section of `CLAUDE.md` both spell out the rerun
command and the invariant, so the next agent doesn't have to
re-derive any of this.
https://claude.ai/code/session_013Bi4H4YQ5or5HtMB4doUFi
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Claude
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688d9afcec
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platformer: end-to-end side-scroller demo + three runtime bug fixes
Adds `examples/platformer.ne`, a full side-scrolling game that
exercises nearly every subsystem of the compiler in one program:
custom CHR tileset, 32×30 background nametable with per-region
attribute palettes, 2×2 metasprite hero with gravity/jump physics,
wrap-around horizontal scrolling, moving enemies, coin pickups,
user-declared SFX + music, and a Title → Playing state machine
with autopilot so the headless jsnes harness captures real
gameplay at frame 180. Tile art + nametable are generated by
`scripts/gen_platformer_tiles.rs` (`cargo run --bin gen_platformer_tiles`).
Building this out uncovered three independent runtime bugs that
together made the example render as black-on-black smileys. All
three are fixed in this commit:
1. **`gen_init` enabled sprite rendering before the linker's
initial palette/background load runs.** The PPU's v-register
auto-increments on every `$2007` write *during active
rendering*, so the palette load (32 B) and nametable load
(1024 B) were scrambled past the first ~72 bytes — every
existing program with a `background Level { ... }` block was
silently rendering zero-filled VRAM. Fix: leave `PPU_MASK = 0`
at the end of `gen_init` and emit a new `gen_enable_rendering`
call *after* all initial VRAM writes complete.
2. **Audio tick corrupted `ZP_CURRENT_STATE`.** The audio
driver's period-table lookup reused `$02/$03` as a temporary
indirect pointer with a comment claiming the slots were free
because the tick doesn't call mul/div. But `$03` is also
`ZP_CURRENT_STATE` used by the state dispatch loop, so every
music note silently overwrote the state index with the high
byte of `__period_table` (`0xC5` in the platformer ROM),
wedging the state machine forever. Fix: `gen_nmi` now PHAs
`$02/$03` on entry and PLA-restores them on exit, and the
audio tick JSR moves inside that save/restore window (it used
to be spliced by the linker *before* the register saves, so
even A/X/Y were technically being trashed pre-save). Only
`audio_demo`'s audio hash shifts (its note timings move a few
cycles); every other golden is unchanged.
3. **Sub-palette mirroring footgun.** Writing a 32-byte palette
blob sequentially causes the sprite sub-palettes' "index 0"
slots at `$3F10/$3F14/$3F18/$3F1C` to clobber the background
universal colour at `$3F00/$3F04/$3F08/$3F0C` via NES hardware
mirroring. The example's palette sets all eight first bytes
to `$22` (sky blue) for this reason; `docs/future-work.md`
picks up a TODO to warn on inconsistent first-byte values in
the analyzer.
Also:
- `docs/platformer.gif` — 6-second recording of the example
running in jsnes, generated by the new
`tests/emulator/record_gif.mjs` puppeteer helper (encodes via
`gifenc`, committed as a dev-dependency under
`tests/emulator/package.json`).
- README / examples/README tables and the 497-test count are
updated to cover the new example.
https://claude.ai/code/session_01BcCcHi6FUmTh8jC7UgkA3A
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