Files

T

thejayman77 064484c50d Ch443f: coherent Gray readiness CDC + qualified scanout underflow detector

Harden the LPDDR scanout underflow diagnostic (Codex direction). Keeps the
Ch443e 4-buffer + lead-2 fix; adds no 5th buffer.

RTL (gs_lpddr_scanout_lb):
- Replace the raw-binary next_fetch readiness sync with a reset-aware GRAY
  code. next_fetch is monotonic between frames, so one Gray bit changes per
  increment; the 2-FF-synced + decoded nf_v is always a real prior frontier
  (monotone, burst-safe), never a torn multi-bit combination. (A plain
  toggle-per-change handshake dropped bursts when two increments landed in one
  sync window; that is why the earlier attempt under-read nf_v and false-tripped.)
  fs_edge_v overrides the lone multi-bit reset transient.
- Qualify the underflow: only a miss persisting >= QUAL_CYCLES (4) sets sticky
  underflow. uf_pmax_q records the longest streak and uf_qual_q whether any
  qualified, so a host can distinguish a 1-cycle CDC lag from a real late row.
- Atomic snapshot: scan_y/nf_v/pmax/causes/vphase/line_valid all latched the
  same video cycle on the first qualified miss.

ABI: 0x120 adds [15:12]=live pmax (2-FF synced via scan_diag_pmax_i). 0x124
[29:20] now carries pmax-at-capture (was nf_s0). Bridge dst reg kept 10-bit.

SDC: scanout diag bundle source count 37 -> 31 (nf_s0[10] -> pmax[4]); new
async-in cut + max_skew/net_delay for the next_fetch Gray CDC; stage-0 cut for
the live pmax sync.

Tests: new tb_gs_scanout_cdc_qual (async-clock focused: no false event from the
readiness transition or ordinary sync latency; sub-QUAL transient does not
qualify; genuine late row qualifies with a self-consistent atomic snapshot;
frame reset + mod-4 reuse re-arm the detector). tb_gs_scanout_diag updated for
the pmax field. Tie off scan_diag_pmax_i (+ pre-existing clut_* gap from the
fog baseline) in the four .* bridge/integration TBs.

Regressions green: scanout (cdc_qual, binomial_lookahead, diag, restart,
lpddr_scanout_lb x3), regbuf (r/aw/w), bridge + 3 pad integration TBs, and the
f52 top-level golden FB (Z 0/307200, COLOR 0/245760 mismatch, drops=0).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

2026-07-23 23:17:41 -04:00

clut_loader_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

clut_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

ee_gs_priv_bridge_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gif_image_xfer_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gif_packed_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gif_path_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_alpha_blend.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_async_fifo.sv

Ch440 review fixes: 93-bit per-bank test coverage + soften M20K claims [READY FOR REVIEW]

2026-07-21 10:28:31 -04:00

gs_axi_aw_regbuf.sv

Ch443: combined timing repair for both Ch442 setup families

2026-07-22 11:19:09 -04:00

gs_axi_r_regbuf.sv

Ch443d: registered AXI R buffer (texcache fill) + drop fill_data_q reset

2026-07-23 10:03:01 -04:00

gs_axi_w_regbuf.sv

Ch441: one-entry fully-registered W buffer, Z-RMW master -> wr_arb s2 [READY FOR REVIEW]

2026-07-21 14:12:11 -04:00

gs_grad_divider.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_lpddr_axi_master.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_lpddr_color_blend.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_lpddr_fb_writer.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_lpddr_map_pkg.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_lpddr_rd_arb.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_lpddr_rd_probe.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_lpddr_scanout_lb.sv

Ch443f: coherent Gray readiness CDC + qualified scanout underflow detector

2026-07-23 23:17:41 -04:00

gs_lpddr_scanout.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_lpddr_wr_arb.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_lpddr_wr_probe.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_lpddr_z_rmw.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_lpddr_zc_emit.sv

Ch443: combined timing repair for both Ch442 setup families

2026-07-22 11:19:09 -04:00

gs_pcrtc_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_persp_uv.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_prim_list_feeder.sv

Snapshot: fog implementation + fidelity tooling baseline (pre bilinear-clamp fix)

2026-07-20 19:56:46 -04:00

gs_reciprocal_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_stub.sv

Add FOG_ENABLE param, prune fog cone on the board profile (fix -6.165ns setup)

2026-07-20 21:31:14 -04:00

gs_swizzle_psmct16_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_swizzle_psmct32_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_swizzle_psmt4_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_swizzle_psmt8_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_texel_addr.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_texture_cache.sv

Ch443d: registered AXI R buffer (texcache fill) + drop fill_data_q reset

2026-07-23 10:03:01 -04:00

gs_texture_unit.sv

Fix signoff timing: remove dead bilinear clamp (comb loop) + relax gray skew 2.0->2.5ns

2026-07-20 20:03:42 -04:00

gs_tile_ram.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_tile_reload.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

gs_z_flush_writer.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

README.md

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

vram_bram_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

vram_normalize_pkg.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

vram_stub.sv

Initial commit: retroDE_ps2 — first-of-its-kind PS2 GS FPGA core (DE25-Nano / Agilex 5)

2026-06-29 20:10:50 -04:00

README.md

rtl/gif_gs

GIF path and Graphics Synthesizer logic. Matches docs/contracts/gif_gs.md.

Current contents

gs_stub.sv — GS shell with two architecturally distinct write ports (Ch75 namespace split):
- reg_wr_* — privileged-block writes (16-bit offset within 0x12000000). Latches BGCOLOR (offset 0x00E0) into bg_{r,g,b}; other offsets emit EV_MODE.
- gif_reg_* — GIF A+D register-number writes (8-bit reg# + 64-bit data). Decodes PRIM=0x00, RGBAQ=0x01, XYZF2=0x04, XYZ2=0x05, FRAME_1=0x4C, ZBUF_1=0x4E into per-register 64-bit latches; unknown reg numbers emit EV_MODE.
- No VRAM, no drawing yet — that is the next architectural step.
gif_path_stub.sv — Wave 2 minimal GIF packet logger; project-local single-qword register-write format. Used by tb_bgcolor_via_dma.
gif_packed_stub.sv — real PS2 GIFtag parser (Ch72-Ch75). Handles PACKED (FLG=0), REGLIST (FLG=1), IMAGE (FLG=2), DISABLE (FLG=3). The REAL_AD_REG_MAP parameter selects the A+D dispatch port:
- REAL_AD_REG_MAP=0 (default, back-compat) — drives gs_stub.reg_wr_* using a project-local 16-bit offset carried in in_data[79:64].
- REAL_AD_REG_MAP=1 — drives gs_stub.gif_reg_* using the real PS2 8-bit reg# carried in in_data[71:64]. Source-of-truth: PCSX2 GSRegs.h.

BGCOLOR reset value

At reset, bg_{r,g,b} default to 0x40 each (mid-grey) rather than black. Rationale: this makes "gs_stub reset but no BGCOLOR write yet" visually distinct from "video output disabled / black frame" in Milestone A. Override is a BGCOLOR write from the test harness.

Pitfall: namespace conflation

Ch74 conflated GIF A+D reg numbers with GS privileged-block offsets and mapped e.g. 0x14→PMODE@0x0000. That is fiction — those are separate namespaces. Ch75 split them. ZBUF_1 is 0x4E, not 0x4F (that's ZBUF_2). When adding a new GIF-context register, source the reg# from PCSX2 GSRegs.h, never from the privileged-block map.