The 16:9 edge pop-in is the parallax 2D BACKDROP layer (ocean/cloud/mountain/
grass), drawn by overlay actor handlers (FUN_801216bc family) that compute
screenX = (worldX - camX) >> parallax in pure integer math and store it to the
object's +0x12 field WITHOUT the GTE — so the GTE X-squash that gives 3D the
wider 16:9 FOV never reaches them and far pieces sit past the 320px edge,
clipped (the blue void / half-rectangles at the edges). See TombaRecomp
ISSUES.md #8C for the full root-cause trail.
Fix = psx_ws_backdrop_x() (gpu.c): squash screenX around screen-centre by the
same ws factor as the GTE, identity at 4:3. Applied on BOTH execution paths
because overlay code runs interpreted when no cache DLL is loaded (the common
case in dev — see #8G):
- Native: recompiler emits write_half(.., psx_ws_backdrop_x(rt)) at the
[widescreen.backdrop] x_sites store (config_loader + code_generator +
main_psx --ws-config so the overlay compile gets the sites). Forwarded into
overlay DLLs via OverlayCallbacks {ws_backdrop_x, ws_x_margin, ws_sprite_tag}
(overlay ABI v2->v3 as the cache discriminator); compile_overlays.py glue +
--ws-config passthrough.
- Interp: dirty_ram_interp SH hook keyed by psx_ws_is_backdrop_site(pc); the
runtime registers the x_sites from game.toml (main.cpp).
Verified in data: backdrop slot screenX squashes 371 -> 318 (pulled on-screen).
PARTIAL: visible culling persists -> remaining cause is the backdrop spawn/
despawn window (separate from screenX clip); see #8C "REMAINING CAUSE".
Also added (earlier this session): ws_census draw ring, ws_margin override,
gpu_state ws fields.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Bug D root cause (Tomba chest freeze, also QA issue #1): the game's own
dispatcher func_80056E08 has a dead jumptable case (type 0x21 ->
jal 0x80120B3C) whose target is mid-function in EVERY overlay variant on
the disc (only the boot EXE references it; the real handler entry is
0x80120AC8). Entering mid-function skips the prologue, runs an epilogue
for a frame that was never pushed, and returns through garbage. Our C
model then resumed the suspended generated continuations on the moved
guest stack -> double-executed tails -> infinite zombie loop (~3K wild
calls/frame) -> MMIO fatal. Family root of Bugs A/C/D.
The contract: a generated C continuation may only run if the guest
actually arrived at it ($ra == call site return address, $sp == caller
sp at the call). Violations begin a "bail" unwind: cpu->pc := the wild
jr's true target, every generated frame returns immediately, and the
unwind resolves at the first enclosing site whose contract matches (or
flattens at the outermost dispatch loop, re-dispatching the wild target
on a clean host stack -- matching real-HW one-stack semantics).
- cpu_state.h: bail state + psx_call_contract() helper (+ overlay-DLL
pointer indirection under PSX_OVERLAY_DLL_BUILD)
- emitters: (ra, sp) checks at every BIOS and game jal/jalr site;
psx_dispatch_impl validates pc==0 and stop-hits against (stop, sp),
handles bail resolve/propagate/flatten
- dirty_ram_interp: surfaced calls validate the contract on return;
bail aborts the interp run; tail transfers into compiled code now run
with pc cleared (closes a latent double-run on plain C returns)
- overlay cache ABI v2: DLLs export overlay_abi(); loader rejects and
deletes stale DLLs (autocompile regenerates with contract checks)
- telemetry: bail_first/resolved/flattened/anomaly in heartbeat + dump
headers; anomaly guard at exception entry; TCP_COMMANDS.md docs
Verified: BIOS+Tomba regen, boot to intro at locked 60.0 fps, all bail
counters 0 through boot/title/attract (no false positives). Chest-area
gameplay verification pending (requires user play).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Extend the overlay JIT cache below the 0x98000 floor to kernel RAM
[0, 0x10000) — the BIOS part-2 image + install-at-runtime stubs
(Rule 18), dominated by the SIO data-byte slot at 0xCF0 whose
install-slot hook tail-dispatches the whole exception-handler tail
into the interpreter on EVERY exception once installed.
Window model (dirty_ram_interp.h): two capture/candidate windows —
kernel [0, 0x10000) and overlay [0x98000, RAM); main-EXE text between
them is statically recompiled, never captured. Interp local-flow gates
intentionally stay overlay-only (kernel runs per-block in exception
context; named constant documents this).
- overlay_capture: per-window dirty-run enumeration, runs clamped at
window edges (kernel CPU-write pages and main-EXE DMA pages can be
adjacent; never merge them).
- overlay_loader: dispatch lazy-load gate covers both windows;
scan_cache_dir validates the <addr8>_<crc8>.dll shape explicitly
(kernel region_start 0 is legal, zero-parse is no longer a sentinel).
- classifier (compile_overlays.py): kernel-window-only DISPATCH_ROOT
promotion — an orphan dispatch interior no rooted walk covers has no
host to truncate and is a real execution root by construction (the
static install-slot hooks tail-dispatch into it). One orphan per
iteration so remaining orphans alias into the new host. Overlay
regions stay ineligible (cross-variant per-PC evidence: 0xE889C class).
- main_psx --overlay: 'dispatch_root' seed lines are trusted walk roots
(exempt from the boundary re-check); seed range is now the loaded
image's own bounds (the old hardcoded [0x80010000,0x80200000) window
silently dropped kernel seeds).
- overlay_api/loader/DLL preamble: route psx_restore_state_escape
through OverlayCallbacks (appended last, by-value copy keeps old
DLLs compatible) — exception-context kernel code longjmp-returns.
Tomba verified (user-played: title -> LOAD list renders -> save loads
-> overworld laps): kernel interp per-PC rows 3 -> 0 (was 0xCF0 =
61,775 dispatches / 2.71M insns at the LOAD screen alone, ~4.6M
insns/session); host func [0xCF0,0xEA0) + 0xDF8/0xE08 aliases, audit
clean; dispatch_native 357,763; dispatch_miss_total 0; interp aborts 0.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Reinstates the runtime-loaded overlay DLL cache (Layer A) and the offline
overlay compilation pipeline that were built on the pruned codex/cache-discovery
branch (tip 2bbafc2) and never merged. Ported onto current master; rebuilt
rather than history-restored.
Runtime (off by default, opt in via [runtime] overlay_cache = true):
- overlay_loader.c/.h, overlay_api.h: CRC32-keyed DLL cache at
cache/<game_id>/<region>_<crc>.dll. On a dirty-RAM dispatch miss the loader
LoadLibrary's the matching DLL, wires runtime callbacks via overlay_init(),
enumerates func_XXXXXXXX exports, and dispatches them BEFORE the interpreter.
- overlay_capture.c/.h: write-once capture set; records overlay DMA bytes and
writes overlay_captures.json (execution-verified seeds) at clean exit.
- dma.c: capture + cd_dma_log hook at CD DMA completion (async model).
- cdrom.c: cdrom_get_setloc_lba() for disc-position correlation.
- dirty_ram_interp.c: g_dirty_ram_exec_pc_table (exec-verified PCs), a
decodability guard on JAL-into-dirty targets, and the overlay dispatch hooks.
- debug_server.c: cd_read_log + overlay_loader_status TCP commands.
- config_loader: [runtime] overlay_cache flag (default false).
Recompiler (compile_overlays.py / extract_overlays.py drive these):
- main_psx.cpp --overlay-exact: analyze only explicit entries + direct JAL
targets and set split_mid_function_targets=false, so overlay basic-block
targets are NOT split into bogus standalone functions (the mid-function-seed
failure mode that produced black-on-load / blue-on-new-game).
- function_analysis.cpp: analyze_exact_entries(); code_generator.cpp: gate the
mid-function split pre-pass behind split_mid_function_targets (default true,
so normal main-EXE codegen is unchanged - Tomba still regens to 2854 funcs).
Deltas from the original: save states dropped (never worked); overlay enable is
runtime-config-gated (off by default) instead of a build-time define; loader
stderr logging converted to the overlay_loader_status TCP path (CLAUDE.md Rule 3).
Recovered from _backups/2026-06-06-consolidation/psxrecomp-all-PRE.bundle.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Matthew Stanley