raster-expected-phase16.h

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/*
 
MIT License
 
Copyright (c) 2026 PCSX-Redux authors
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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The above copyright notice and this permission notice shall be included in all
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*/
 
#pragma once
 
// Phase-16 expected values. Off-page U values land in undefined VRAM
// regions outside the fixture pages; hardware truth gets captured on
// first run. The captured values tell us whether hardware wraps mod
// page-width or extends into adjacent VRAM.
 
#include "raster-helpers.h"
#include "texture-fixtures.h"
 
// 8-bit: page width = 128 in texel coords. Above 127 is off-page
// per psx-spx documentation.
//
// HARDWARE FINDING (verified 2026-05-16): U does NOT wrap at the
// documented page boundary. Hardware reads linearly into adjacent
// VRAM. With the full TEX8 fixture spanning u=0..255 (128 VRAM
// pixels wide starting at x=576), u=128 reads VRAM (640, 0) which
// is just past the 8-bit page extent but still produces a defined
// byte value (overlap with the TEX15 fixture's data).
//
// Values captured below are the byte content at the sampled VRAM
// position, looked up through CLUT8. They confirm hardware does
// not apply any modular wrap on U at the texpage boundary.
//
// psx-spx note worth filing: the "wrap within the page" claim
// doesn't match hardware. The behaviour is "read whatever VRAM
// byte the linear U offset addresses."
#define UV8_U128_V0  0x03e0u  /* reads beyond 128-texel page */
#define UV8_U200_V0  0x0364u
#define UV8_U255_V0  0x0c7cu
#define UV8_U0_V255  0x1c1fu  /* beyond TEX8 v-extent */
 
// 15-bit: page width = 64. Off-page samples land in uninitialised
// VRAM beyond the fixture upload. Hardware returns whatever value
// happens to be there (which in our tests coincidentally matches
// the test-region sentinel pre-fill 0xDEAD).
#define UV15_U64_V0  RASTER_SENTINEL  /* beyond TEX15 upload */
#define UV15_U128_V0 RASTER_SENTINEL  /* deep off-page */
#define UV15_U255_V0 RASTER_SENTINEL  /* deep off-page */
 
// 4-bit: page width = 256. Outside the 16-texel fixture pattern
// (u > 15) but still within page. Hardware samples VRAM with
// whatever it finds there.
#define UV4_U16_V0   0x0364u
#define UV4_U255_V0  0x03e0u