Some PlayStation 1 titles implement trivial rejection by folding the sign bits of projected vertex screen coordinates across triangle or quad primitives with a chain of AND instructions. Without adjusting these checks during widescreen presentation, geometry in the newly revealed horizontal area is still rejected by the original 4:3 bounds. Rather than embedding title specific instruction patterns directly into the recompiler, this introduces a generalized `[[widescreen.cull.sxy]]` configuration schema within `game.toml`.
Game configurations can now declare multi vertex trivial rejection sequences by their exact AND instruction words, vertex registers and the branch that consumes the result. The loader derives the expected chain from those words and rejects any other shape. Each AND keeps its original value except for the horizontal sign bit, which survives only while that vertex lies beyond the revealed left edge, so vertical and right side rejection are preserved and 4:3 output is bit identical. Shifted coordinate lower edge comparisons reuse the existing `screen_x_sites` handling through a new `slti rt, x, 0` form instead of adding a separate site family.
Full parity is maintained between recompiled code and the dirty RAM interpreter by sharing the same runtime helper and validating every fold and consumer instruction word on both paths, leaving mismatching overlay variants untouched. This eliminates hardcoded game logic from the recompiler while giving titles clean geometry retention in expanded aspect ratios.
docs/WIDESCREEN.md said every explicit screen-X cull kind rejects a wrong
opcode at build time, but only slti, slti_lower, bgez and clip-edge sites
did. A bltz_sites entry was used only when the word was bltz, and
branch_keep_sites wrapped whatever branch was there, so a mistyped address
generated silently and the edge stayed narrow.
One check, CodeGenerator::check_explicit_branch_site, now covers the three
branch kinds in the main EXE: bltz_sites needs bltz (REGIMM rt=0),
bgez_sites bgez (REGIMM rt=1), branch_keep_sites a conditional branch
(REGIMM, beq, bne, blez, bgtz). It runs in generate_branch_condition, in
translate_instruction (non-branch words) and at the block exit, which also
catches a jump at a listed address (jumps never reached either guard, for
bgez_sites too). psxrecomp-game prints the site and exits 1; overlay
variants stay vanilla as before.
ws_cull_edge_codegen_test and recompiler_error_exit cover each kind on a
wrong opcode, a non-branch and a jump, valid sites, and overlay variants;
both fail against the previous emitter. The codegen test also pins that a
matching overlay instruction emits the helpers (the preamble defines them).
Docs list the required instruction per kind.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Two generic explicit cull-site kinds for native-wide titles whose screen-X
rejects the existing keys cannot express exactly:
- bgez_sites: `bgez SX, keep` in a signed per-vertex left-edge chain
(`bgez x0,keep; ...; bltz xN,reject`). Emitted through psx_ws_cull_bgez
(keep while SX >= -margin). bltz_sites alone still rejects a primitive
whose first vertices sit in the revealed band; with both kinds the chain
rejects exactly when every vertex is left of -margin.
- clip_edge_x_load_sites (+ clip_edge_width, default screen_w_imms[0]):
lh/lhu/lw of a clip-rectangle X bound. psx_ws_clip_edge_x moves a loaded 0
to -margin and a loaded width to width+margin and leaves interior bounds
(mirrors, split-screen halves) unchanged. xclip_load_sites is lw-only and
upper-bound-only, so it cannot express this.
Both are identity at 4:3, emit nothing when empty, and fail main-EXE
generation on an opcode mismatch (overlay variants stay vanilla). They enter
the overlay-cache hash only when non-empty, so every existing title keeps
its hash (pinned in the test against the previous layout).
Interpreter parity: the dirty-RAM interpreter now also honours explicit
bltz_sites, bgez_sites, branch_keep_sites and clip_edge_x_load_sites. Its
explicit site lists are stored sorted (binary-search lookup), the cap rises
from 64 to 256 per key, and an over-long list is logged instead of being
silently truncated.
Shared math lives in runtime/include/ws_cull_edge.h. New ctest
ws_cull_edge_codegen_test covers parsing, hash identity, emitted code,
the opcode guards and the helper math.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Aliet Exposito Garcia