Adds PCSX-Redux's MIT-licensed OpenBIOS as a second BIOS the framework can
statically recompile, next to retail SCPH1001. Because OpenBIOS is
redistributable, a game verified against it ships its BIOS with the build —
players supply only a disc, and the launcher BIOS picker disappears.
The mechanism is general, not OpenBIOS-specific: every BIOS image gets a
bios/<STEM>.toml profile that is the single source of truth for its identity
and layout.
Recompiler
- bios/<STEM>.toml profiles: [program.image] (sha256 pin, redistributable
flag), [recompiler.address_model] (boot-time ROM->RAM copy windows,
kernel-bless window), install_slots, and [recompiler.runtime_exports]
HLE anchors (0 = feature structurally unavailable on that BIOS).
- BiosAddressModel (new): validated model built from the profile, replacing
~9 hardcoded SCPH1001 window constants that had drifted apart across the
emitter / discovery / game codegen. The emitted C normalize() derives
from the same table. from_config rejects overlapping/misaligned windows
and orderings where sequential folding != first-match. A CTest-registered
equivalence test sweeps every RAM/ROM address against verbatim copies of
the old helpers.
- Orphaned delay slots (the OpenBIOS-critical emitter fixes): jr/jalr
slots are inlined before the jump resolves — previously their side
effect was silently LOST (e.g. a case-return fragment's addiu $sp pop,
which unwound a shifted frame and walked the exception handler's IntRP
cursor into a wild dispatch). Orphaned branches resume at ds+4 on
not-taken instead of re-executing the slot (a read-modify-write slot
doubling twice broke OpenBIOS readPad). Jump targets latch pre-slot.
- MIPS-I load-delay modeling for dependent load pairs: the successor sees
the pre-load value (OpenBIOS's cardfasttrack.s relies on it on purpose —
"gotta break those bad emulators"). Unmodeled shapes warn at build time.
- Discovery hardening: branch-target dispatchability closure to fixpoint;
jump tables placed at jr+8 no longer walked as code; cross-function
continuations routed by an instruction->owner map.
- Signed MULT support (unreachable from the retail seed set; modern-GCC
OpenBIOS emits it freely), latency-modeled like MULTU.
- Seeds from ELF symbol tables + data-section code-pointer harvest
(tools/gen_bios_seeds_from_elf.py) — a source-built BIOS needs no
disassembly pass. 646 OpenBIOS seeds, incl. 5 empirical dispatch-miss
seeds.
- Stemmed outputs (<out_stem>_full.c / _dispatch.c) so two BIOSes coexist
in one out_dir. tools/regen_bios.sh is profile-driven (--config).
Runtime
- psx_bios_image: the generated dispatch now self-describes the BIOS it
was compiled from (identity: size/CRC32/SHA-256/wordsum; kernel-bless
window; HLE anchors; bundled flag). Runtime SCPH1001 hardcodes removed.
- Launch check is a hard identity gate (a mismatched image under
statically recompiled code is a guaranteed wild jump). Bundled builds
hide the BIOS picker and treat a missing/tampered bundled image as an
installation defect.
- Faithfulness fixes surfaced by OpenBIOS's tighter timing loops (all
global, argued in code comments, regression-tested against SCPH1001):
- SIO pad RX is cycle-paced like the memcard path (RX_RDY at
shift-complete, ACK +170); total ack-IRQ latency unchanged.
PSX_SIO_PAD_SYNC_RX=1 restores the legacy synchronous path for A/B.
- SPUSTAT derived from SPUCNT instead of permanently-asserted busy.
- GPUSTAT.13 (interlace field) alternates per vblank while interlaced,
pinned 0 in progressive.
- CD Init(0x0A) completes in ~3.9 ms instead of borrowing Beetle's
34 ms Reset figure (OpenBIOS's short bounded retry loop livelocked).
- Exception EPC guard accepts ROM-window block leaders, not just RAM.
- New TCP debug commands (documented in TCP_COMMANDS.md): bios_info,
s3_smear_watch, callret_watch; write-trace ring gains $s0-$s5.
bios/openbios.bin is vendored (MIT — notice in bios/OpenBIOS.LICENSE,
attribution in THIRD_PARTY_ATTRIBUTION.md, source pin + build recipe in
bios/OpenBIOS.toml). The emitter fingerprint digest is now content-only:
existing generated/*.emitter.sha will read STALE once; re-run
tools/regen_bios.sh.
Henrique Guedes