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

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>

tools/test_ps2_feeder.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+# retroDE_ps2 — Ch339 host-encoder gate. Compiles ps2_feeder and proves its staging output is
+# BYTE-EQUIVALENT to the golden bake.py fixtures for every representative Ch333-338 scene, then
+# checks that malformed / oversized / out-of-range commands are rejected cleanly. No board needed.
+set -u
+HERE="$(cd "$(dirname "$0")" && pwd)"
+REPO="$(cd "$HERE/.." && pwd)"
+MEM="$REPO/sim/data/top_psmct32_raster_demo"
+BIN="$(mktemp -d)/ps2_feeder"
+fail=0
+
+echo "== compile =="
+gcc -O2 -Wall -Werror -o "$BIN" "$HERE/ps2_feeder.c" || { echo "COMPILE FAILED"; exit 1; }
+
+echo "== regenerate goldens =="
+python3 "$MEM/bake.py" >/dev/null 2>&1 || { echo "bake.py failed"; exit 1; }
+
+echo "== byte-equivalence vs golden .mem =="
+check() {  # $1 scene  $2 golden.mem
+    "$BIN" --dump "$1" > /tmp/_dump.txt 2>/tmp/_err.txt
+    tail -n +3 "$MEM/$2" > /tmp/_gold.txt
+    if diff /tmp/_dump.txt /tmp/_gold.txt >/dev/null 2>&1; then
+        echo "  MATCH    $1 == $2"
+    else
+        echo "  MISMATCH $1 != $2"; fail=1
+    fi
+}
+check color-tri      feeder_color_tri.mem
+check native-rect    feeder_native_rect.mem
+check gouraud-tri    feeder_gouraud_tri.mem
+check accum          feeder_accum.mem
+check retrigger-a    feeder_scene_a.mem
+check retrigger-b    feeder_scene_b.mem
+check zpersist-near  feeder_zpersist_near_first.mem
+check zpersist-far   feeder_zpersist_far_first.mem
+check zpersist-grad  feeder_zpersist_grad.mem
+check sprite         feeder_sprite.mem      # Ch345a — runtime textured-alpha SPRITE staging
+
+echo "== rejection of bad input (each must exit non-zero) =="
+reject() {  # $1 label ; rest = file contents on stdin
+    cat > /tmp/_sc.txt
+    if "$BIN" --dry-run -f /tmp/_sc.txt >/dev/null 2>&1; then echo "  NOT-REJECTED $1"; fail=1; else echo "  rejected     $1"; fi
+}
+yes 'tritile 0 0x5000 255 0 0' | head -28 | reject "oversized (28 tris)"
+printf 'tri 1 2 3\n'                  | reject "malformed tri"
+printf 'tritile 99 0x5000 255 0 0\n'  | reject "tile out of range"
+printf 'bogus 1 2 3\n'                | reject "unknown op"
+
+echo "RESULT: $([ $fail -eq 0 ] && echo PASS || echo FAIL)"
+exit $fail