pysidtracker

Shared base for the pure-Python C64 SID tracker parsers (pygoattracker, pysidwizard, pydmcsid, pyfuturecomposer, pymusicassembler, pydefmon, pyjch, pysoundmonitor).

Reads .sid containers (PSID/RSID) and bare .prg images into a 64 KiB C64 memory model, and detects packed/relocating playroutines by running the tune's init in a 6502 emulator — container headers are not trusted. Each format package subclasses BaseSidParser for a consistent read / parse / detect API.

Components

• parse_sid_header / SidHeader — PSID/RSID container header parsing.
• SidImage — a loaded 64 KiB C64 memory image with absolute-addressed accessors, from a .sid container or a bare .prg.
• read_bytes — path / bytes / file-like source dispatch.
• SidError hierarchy — SidParseError, SidFormatError, EmulatorUnavailable.
• detect_playroutine / PlayroutineKind — static signature recognition, then an emulated init run to classify DIRECT / RELOCATED / PACKED / UNKNOWN.
• BaseSidParser — the base class each format subclasses.
• CodePattern / find_code_all / find_code_first — masked 6502 code-fragment search with operand capture.
• registers — C64 hardware register map (SID/CIA/VIC, IRQ/NMI and CPU vectors) with predicates and find_register_stores.
• trace_init / InitTrace — run a tune's init under a write observer to report CIA timer cadence and the IRQ/NMI vectors an IRQ-driven header hides.
• emu — the shared jennings host every init/replay path runs on: wire_mpu (native NMOS illegal opcodes + cycle-derived VIC/SID reads) and run_to_rts.
• playroutine_cadence / Cadence / TriggerSource — derive the play-routine cadence (raster calls per frame, CIA/NMI timer period) from how the tune programs its interrupts in sidplayfp's PSID driver environment (docs/cadence.md); cadence_check validates it against sidtrace interrupt rows.
• native_decrunch — native exomizer unpack (pydexomizer), an init-free alternative depack path; opt-in via detect_playroutine(..., native=True).
• reglog — RegWrite register-log format (read_reglog / write_reglog) and frame_writes, the shared per-frame SID-write framing loop.
• oracle — per-frame SID register grids: register_grid (jennings), the stdlib grid_from_writes framer, read_sidwr (preframr-sidtrace .sidwr.bin), aligned_match, and the sidtrace (sidplayfp) oracle bridge — run_sidtrace, read_sidtrace, sidtrace_cadence, sidtrace_grid.
• testing — HVSC tune fetch/resolve for test suites (fetch_tune, resolve_tune, make_tune_fixtures), and make_oracle_fixtures / oracle_grid — a reusable byte-exact player-vs-sidtrace-oracle test (docs/oracle-testing.md).
• survey — whole-song HVSC survey and failure triage of any format's renderer against the sidtrace oracle; sidid — pure-Python SIDId with the bundled sidid.cfg (pysidid CLI). pip install "pysidtracker[survey]", docs/survey.md.
• roms — C64 KERNAL/BASIC/CHARGEN ROM fetch + SHA-256 verified cache (fetch_rom, resolve_rom, roms_available) and 64 KiB mapping (rom_image, apply_roms) for tunes that cannot run without the ROMs. The ROMs are copyright works: fetched into a gitignored cache, never committed (docs/c64-roms.md).
• audio — render_player_wav / render_player_samples drive a MemPlayer straight to WAV through an emulated SID (pyresidfp, a core dependency); the lower-level render_wav / render_samples take a bare write stream, plus resolve_device / seconds_to_frames.
• Writers — SidHeader.to_bytes / write_psid / SidImage.to_prg (the inverse of the parsers), parse_prg, and encode_cstr / decode_cstr.
• SidImage absolute-address accessors — byte_at / word_at / contains / poke, relocation-safe and bounds-checked.
• mos6502 — shared 6502 primitives: OP_LEN, opcode-class sets, s8 / adc / sbc, SidWriteCapturingMemory, walk_until.
• MemPlayer — per-frame register-diff player scaffold; subclasses implement _init / _frame. register_writes_from_player drives it to a reglog.
• notefreq — NoteFreqTable, computed PAL/NTSC pitch tables, and locate_note_freq (find hi/lo tables from paired absolute-indexed reads).
• make_package_errors — per-package error hierarchy factory whose *ParseError / *FormatError subclass the base ones, so base except clauses catch them.
• formats / maincli — the one pysidtracker CLI (info / reglog / wav) that discovers installed formats through the pysidtracker.formats entry-point group and runs against each format's parser + player, plus any subcommands it contributes. A format package registers a SidFormat instead of shipping its own CLI. cli holds the underlying argparse scaffold (run_cli, print_info, add_reglog_command, add_wav_command).
• registers additions — SID_VOICES, voice/global register indices, and the attack_decay / sustain_release ADSR nibble packers.
• resolve_entry_points / is_jmp_vector, cadence_from_latch, and the ByteCursor / check / byte_range parse helpers.

Install

pip install pysidtracker   # core: jennings (init emulation), numpy, pyresidfp (WAV render)

All dependencies are core: jennings (detection runs a tune's 6502 init), pydexomizer (native_decrunch unpacks exomizer-packed images natively), pyresidfp (the emulated SID the WAV render drives), and numpy (sample buffers and the image anchor scan).

Usage

from pysidtracker import BaseSidParser, PlayroutineKind

class MyParser(BaseSidParser):
    def recognize(self, image):
        return image.find(b"MYSIG")            # truthy anchor when found
    def parse(self, data, **kw):
        image = self.load_image(data)          # .sid or .prg -> SidImage
        ...                                    # decode image.mem into a model

det = MyParser().detect("tune.sid")
if det.kind is PlayroutineKind.PACKED:
    ...                                        # header was not trustworthy

Development

pip install -e ".[dev]"
pytest --cov=pysidtracker

See docs/design.md for the detection model and shared primitives.

License

Apache 2.0 — see LICENSE.