Per Codex review of 471c1af:
1. tb_gs_async_fifo QUAD_WIDTH4 variant now runs at the PRODUCTION 93-bit width
(exercising the odd 23/23/23/24 remainder split) and drives a DISTINCT NONZERO
pattern into every width bank (seq XOR per-bank constants, bank2 inverted), with
the scoreboard checking the FULL reconstructed word. A swapped/broken/zeroed
upper bank now changes the word and trips the scoreboard. Depth-half crossing
(DEPTH=8) + wrap/full coverage retained. mk() is generate-guarded so the 32-bit
variants never elaborate the 93-bit selects.
2. Softened gs_async_fifo comments: 'same total M20K' -> EXPECTED-similar, pending
synthesis (fact -> expectation).
No simulations or Quartus run. Awaiting review before any sim.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Candidate 2 from the accepted structural proposal. Adds a QUAD_WIDTH4_READ
generate branch to gs_async_fifo: like QUADRANT_READ (2 depth x 2 width) but
splits the payload into FOUR width banks, so each preserved read-address launch
register drives ~half the M20K load (targets the 310MHz raddr_hi1_q->mem_hi1
setup family, WNS -0.103). Keeps QUADRANT_READ's proven 2:1 depth OUTPUT selector
unchanged (no new/deeper mux, per the doc's warning). Depth (8192), one-cycle
read latency, ordering, CDC, capacity, and interface are identical.
zc_emit u_req switched QUADRANT_READ->QUAD_WIDTH4_READ. New default-off param
leaves the other two gs_async_fifo instances byte-identical. TB gains a
TEST_QUAD_WIDTH4 variant + standalone Makefile target tb_gs_async_fifo_quad_width4.
NO simulations or Quartus run (per authorization). Awaiting review before any sim.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The fog blend's tex_color*F multiply landed on the texture->color critical path
(u_texcache RAM -> u_tex|tex_color -> mult_126 -> raster_pixel_color_q, 46ns,
-6.165ns setup). Fog is a proven no-op for the current board scene (96.5% F=255),
so pay zero for it here.
FOG_ENABLE (default 1, byte-identical fog) added to gs_stub; each fog mux gated
(FOG_ENABLE && ras_fge) so FOG_ENABLE=0 constant-folds the entire fog cone away
(multiply, FOGCOL adders, s2_fog_f/persp_fog_f5 interp). Threaded through
top_psmct32_raster_demo_bram; set FOG_ENABLE(1'b0) on the active GS_SH3_LPDDR_FB
board arm (elsif at :1086, the one the QSF profile compiles). Fog stays default-on
everywhere else.
Verified: FOG_ENABLE=1 fog TBs unchanged PASS; FOG_ENABLE=0 (new tb_gs_fog_disabled
+ board scene TB) emits raw color = pre-fog datapath; board elaborates clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Per-vertex GS fog end-to-end (gs_stub emit incl. persp_emit5, gs_prim_list_feeder
XYZ2->XYZF2 on PRIM.FGE, gs_make_sh3_scheduler_fixture.py F/FGE packing), new fog
TBs, fidelity attribution tooling. Functional baseline before removing the dead
bilinear lerp8 clamps (Codex: 161-node comb loop -> -0.042ns setup fail).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
RTL (GS rasterizer, EE core stub, platform bridge, LPDDR4B path), sim regression
(272 TBs), docs, and tooling. Copyrighted PS2 content (BIOS, game code, GS dumps,
and all dump-derived textures/traces) is excluded via .gitignore and stays local.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
thejayman77