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https://github.com/imjasonh/nescript
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9a539ea068
Five language features and optimizations from the planned-work backlog: - **Minimal audio driver**: `play`/`start_music`/`stop_music` now generate APU pulse-1/pulse-2 writes from a builtin SFX/music name table, and the NMI handler gains a `JSR __audio_tick` splice (via the linker's `__audio_used` marker lookup) that ages an SFX countdown counter and mutes pulse 1 when the tone expires. Programs that never trigger audio pay zero ROM cost. - **u16 arithmetic and comparisons**: new IR ops `LoadVarHi`, `StoreVarHi`, `Add16`, `Sub16`, and six `Cmp*16` variants. The lowering context tracks variable types via the analyzer's symbol table and routes expressions through the 8-bit or 16-bit path based on operand width. Add16 emits `CLC;ADC;ADC` with carry propagating naturally into the high byte; compares dispatch high-byte-first with a short-circuit low-byte fallback. Fixes a silent miscompile where `big += 1` on a u16 var only incremented the low byte. - **Multi-scanline handlers per state**: `gen_scanline_irq` now dispatches on `(current_state, ZP_SCANLINE_STEP)` and reloads the MMC3 counter with the delta to the next scanline in the same state. `gen_scanline_reload` resets the step counter at the top of each NMI so a state with multiple handlers fires them in ascending line order. Previously only the first handler per state ever fired. - **IR temp slot recycling**: `build_use_counts` pre-scans each function to count per-temp uses; `retire_op_sources` decrements the counts after each op and pushes dead slots back onto `free_slots` for later allocation. `bitwise_ops.ne` used to crash (debug) or miscompile (release) once it hit 128 concurrent temps; with recycling the same function now uses ~4 slots instead of 136. - **INC/DEC peephole fold + improved dead-load elimination**: `fold_inc_dec` collapses `LDA addr; CLC; ADC #1; STA addr` into a single `INC addr` (and the SEC/SBC variant into `DEC addr`), saving 5 bytes and 5 cycles per increment. The fold is suppressed when the next instruction reads carry. `remove_dead_loads` now walks past INC/DEC/STX/STY (which don't touch A) to find the actual next A-use, catching more dead loads. Tests: 331 unit + 39 integration (up from 313 + 37), including new guards for audio, u16, multi-scanline, and slot recycling. https://claude.ai/code/session_01A8qk3gw2jWSzdiXBZPZSFE
48 lines
1.5 KiB
Text
48 lines
1.5 KiB
Text
// Audio Demo — shows off the minimal APU driver.
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//
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// Press a button to trigger each sound effect. Start begins the
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// background tone; Select stops it. The driver uses pulse 1 for
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// SFX and pulse 2 for music, both running out of the built-in
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// NMI audio tick.
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//
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// The SFX name is looked up in a small builtin table of tones:
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// coin — high short blip (also: pickup, collect)
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// jump — mid short tone (also: hop)
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// hit — low short blast (also: damage, explode)
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// click — short beep (also: select, confirm)
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// cancel — low longer tone (also: back, error)
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// shoot — very high short pulse (also: laser, fire)
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// Unknown names play a generic mid-frequency beep.
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//
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// Build: cargo run -- build examples/audio_demo.ne
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// Output: examples/audio_demo.nes
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game "Audio Demo" {
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mapper: NROM
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}
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var px: u8 = 128
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var py: u8 = 120
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on frame {
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// Move the smiley so you can see the game is running.
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if button.right { px += 1 }
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if button.left { px -= 1 }
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if button.down { py += 1 }
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if button.up { py -= 1 }
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// Trigger SFX on d-pad-press equivalents. Using `_pressed`
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// would be nicer but the builtin table keys off the name, so
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// holding a button just retriggers the same tone every frame,
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// which is audible and good for a demo.
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if button.a { play coin }
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if button.b { play jump }
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// Start/stop the background music loop.
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if button.start { start_music theme }
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if button.select { stop_music }
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draw Smiley at: (px, py)
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}
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start Main
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