eb7c6f98cd
Native fmadds/fmsubs/fnmadds/fnmsubs + double siblings via hardware FMA (vfmadd213sd/vfmsub213sd — single rounding, matching the interpreter's correctly-rounded f64::mul_add; negated forms flip the result sign with xorpd, and NaN — which the interpreter preserves unnegated — is caught by the finite guard → deopt, so unconditional negate is exact on the fast path). Gated on a runtime cpuid FMA3 check (emit::host_has_fma, cached OnceLock); on a non-FMA host these arms fall back to the interpreter's software FMA — byte-identical, so goldens hold on any host (NEVER emit mulsd+addsd, which double-rounds). fp_arith_matches extended to the madd family (guarded on host FMA3). All 6-config GOLDEN n200m BYTE-IDENTICAL; 24 xenia-jit tests green. MEASURED (2B-instr run through the video, --gpu-inline, best-of-3) — CLEAN 3-way: interp 72.6s (27.5 MIPS) region JIT (pre-FP) 27.3s (73.2 MIPS) = 2.66x over interp region JIT + native FP 23.3s (85.8 MIPS) = 3.12x over interp So native FP's OWN contribution is ~1.17x (+17%) on top of the region JIT — it removed 62% of all interpreter fallbacks (306.6M→117.3M, the FP-arith share) but that translates to only ~17% wall-time here because the region JIT already made non-FP code fast and the --gpu-inline drain + plumbing dominate the remainder. This matches the conservative ~1.3-1.5x plan estimate (region JIT is the bigger CPU lever on the video; FP is a solid, deterministic increment and a multiplier for a future multi-core mode). Video still ~7x from real-time → multi-core next.
xenia-rs
Rust reimplementation of the Xbox 360 emulator xenia, focused on reverse-engineering and preservation rather than full-speed play. The initial target is Project Sylpheed — Arc of Deception; getting the title disassembled, traced, and far enough into its init path to understand its engine.
Heavy cross-reference to xenia-canary for CPU context setup, kernel export behavior, and XEX loading semantics.
Status
- XEX loader — XEX2 header parsing, LZX decompression, AES decryption, PE section parsing.
- VFS / XISO — XGD2 dual-layer disc images (with the 0x0FD90000 partition offset).
- PPC interpreter — 200+ opcodes, PowerPC 32/64-bit GPR/FPR, VMX128 decoding.
- Static analyzer — function discovery (prolog/epilog heuristics), cross-references, labels, save/restore helper detection, assembly text + SQLite database output.
- Kernel HLE — minimal subset driving Project Sylpheed: ~170 xboxkrnl + xam exports (critical sections, events, TLS, virtual memory, Vd stubs, XAM input/user/content).
- Debugger — in-memory step/break, SQLite execution + import-call + branch tracing.
Not yet: GPU (xenos/xe-shader), APU audio, HID, kernel scheduler, full threading, exception delivery.
Workspace
crates/
xenia-types # shared primitive types, bitflags
xenia-memory # guest memory, paged allocator, page table
xenia-cpu # PPC decoder, interpreter, context
xenia-xex # XEX2 loader, PE parser, LZX, AES
xenia-vfs # XISO / disc-image reader
xenia-kernel # HLE kernel state, exports, XAM
xenia-gpu # (stub) Xenos command processor
xenia-apu # (stub) XAudio
xenia-hid # (stub) XInput
xenia-debugger # in-memory trace, breakpoints, step modes
xenia-analysis # function/xref analysis, assembly formatter, SQLite DbWriter
xenia-app # `xenia-rs` CLI binary
CLI
Build:
cargo build --release
The binary xenia-rs accepts XEX2 files or ISO / XISO disc images as input
(the loader auto-detects discs and extracts default.xex).
info / browse / disasm
Quick header / disc / first-N-instructions inspection. See --help.
extract — unpack PE + metadata
xenia-rs extract <xex-or-iso> [-o <out-dir>] [--db <sqlite-path>]
Writes <name>.pe (decompressed/decrypted PE image) and <name>.xex.json
(header metadata). With --db, also emits a SQLite database containing the
base tables: metadata, sections, imports.
dis — full disassembly
xenia-rs dis <xex-or-iso> [-o <asm-file>] [--db <sqlite-path>] [--quiet]
Runs function + cross-reference analysis and produces:
- assembly text to stdout or
-o <file>(unless--quiet) - optional SQLite DB with the base tables + disasm tables:
functions,labels,instructions,xrefs
exec — interpret with tracing
xenia-rs exec <xex-or-iso> [-n <max-instrs>] [--db <sqlite-path>]
[--trace-instructions] [--trace-imports] [--trace-branches]
Loads the title, initializes CPU state per xenia-canary, intercepts import
thunks with HLE kernel calls, and interprets from the entry point. Without
-n, runs until halt/fault. With --db, produces a DB that is a superset
of dis --db plus opt-in trace tables:
| flag | table | rows |
|---|---|---|
--trace-instructions |
exec_trace |
one row per interpreted instruction (PC, r3/r4, LR, SP) |
--trace-imports |
import_calls |
one row per kernel/XAM call (module, ordinal, args) |
--trace-branches |
branch_trace |
taken branches classified as call/return/jump/branch |
Cumulative DB layering
Each command's DB is a superset of the previous. A single
xenia-rs exec <iso> --db full.db --trace-instructions --trace-imports --trace-branches
produces the full picture in one pass — base tables, complete static
disassembly, and runtime traces correlatable by address/cycle.
Performance knobs
XENIA_DB_BATCH_SIZE— rows per streaming commit / trace-buffer flush (default100_000). Lower values reduce memory use; higher values reduce fsync overhead on slow disks.
The DB writer uses journal_mode=OFF, synchronous=OFF, locking_mode=EXCLUSIVE
and commits in batches; no ANALYZE is run at finalize. Indices are created
after bulk insertion with progress messages.
Example queries
-- Top 20 kernel functions called during early init
SELECT name, COUNT(*) FROM import_calls GROUP BY name ORDER BY 2 DESC LIMIT 20;
-- All basic-block leaders (targets of taken branches) not already labelled
SELECT DISTINCT bt.target
FROM branch_trace bt LEFT JOIN labels l ON l.address = bt.target
WHERE l.address IS NULL;
-- Correlate a traced call site with its static disassembly
SELECT et.cycle, i.disasm, i.ext_disasm
FROM exec_trace et JOIN instructions i ON i.address = et.address
WHERE et.address = 0x824AB748 ORDER BY et.cycle;
License
BSD-3-Clause, matching upstream xenia.