From aa99796d8afd6089b4ebc94ca9f7693ac699a31b Mon Sep 17 00:00:00 2001
From: nmzik <Nmzik@mail.ru>
Date: Sat, 18 Jul 2026 03:43:25 +0200
Subject: [PATCH] Fix Standard64KB 16-bit texture swizzle

---
 src/graphics/guest_gpu/tile.cpp        | 21 ++++++++++-----------
 tests/ShaderRecompilerComputeTests.cpp | 20 ++++++++++++++++++++
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/src/graphics/guest_gpu/tile.cpp b/src/graphics/guest_gpu/tile.cpp
index 8084300b3..a88e71079 100644
--- a/src/graphics/guest_gpu/tile.cpp
+++ b/src/graphics/guest_gpu/tile.cpp
@@ -1089,12 +1089,11 @@ struct Standard64KB16Tables {
 	constexpr Standard64KB16Tables() {
 		for (uint32_t i = 0; i < 256; i++) {
 			uint32_t x_part = 0;
-			x_part ^= (i << 1u) & 0x0006u;
-			x_part ^= (i << 4u) & 0x0040u;
-			x_part ^= (i << 5u) & 0x0100u;
-			x_part ^= (i << 6u) & 0x0400u;
-			x_part ^= (i << 7u) & 0x1000u;
-			x_part ^= (i << 8u) & 0x4000u;
+			x_part ^= (i << 1u) & 0x000eu;
+			x_part ^= (i << 4u) & 0x0080u;
+			x_part ^= (i << 5u) & 0x0200u;
+			x_part ^= (i << 6u) & 0x0800u;
+			x_part ^= (i << 7u) & 0x2000u;
 			x_part ^= (i << 8u) & 0x8000u;
 
 			x_words[i] = x_part >> 1u;
@@ -1102,11 +1101,11 @@ struct Standard64KB16Tables {
 
 		for (uint32_t i = 0; i < 128; i++) {
 			uint32_t y_part = 0;
-			y_part ^= (i << 3u) & 0x0038u;
-			y_part ^= (i << 4u) & 0x0080u;
-			y_part ^= (i << 5u) & 0x0200u;
-			y_part ^= (i << 6u) & 0x0800u;
-			y_part ^= (i << 7u) & 0x2000u;
+			y_part ^= (i << 4u) & 0x0070u;
+			y_part ^= (i << 5u) & 0x0100u;
+			y_part ^= (i << 6u) & 0x0400u;
+			y_part ^= (i << 7u) & 0x1000u;
+			y_part ^= (i << 8u) & 0x4000u;
 
 			y_words[i] = y_part >> 1u;
 		}
diff --git a/tests/ShaderRecompilerComputeTests.cpp b/tests/ShaderRecompilerComputeTests.cpp
index 17dfc8199..eaf81f190 100644
--- a/tests/ShaderRecompilerComputeTests.cpp
+++ b/tests/ShaderRecompilerComputeTests.cpp
@@ -10276,6 +10276,26 @@ void CheckStandard64RenderTargetTileRoundTrip() {
               standard[16] == 512 && standard[32] == 4 &&
               standard[16383] == 16383,
           "Standard64KB reciprocal mapping disagreed with the PS5 SDK");
+
+  constexpr uint32_t block_width_16 = 256;
+  constexpr uint32_t block_height_16 = 128;
+  std::vector<uint16_t> tiled_16(block_size / sizeof(uint16_t));
+  for (uint32_t i = 0; i < tiled_16.size(); i++) {
+    tiled_16[i] = static_cast<uint16_t>(i);
+  }
+  std::vector<uint16_t> linear_16(tiled_16.size(), 0xffffu);
+  TileConvertTiledToLinearStandard64KB16(
+      linear_16.data(), tiled_16.data(), block_width_16, block_height_16,
+      block_width_16, block_size);
+  const auto sample_16 = [&](uint32_t x, uint32_t y) {
+    return linear_16[static_cast<uint64_t>(y) * block_width_16 + x];
+  };
+  Require("Standard64RenderTarget", "16-bit SDK byte mapping",
+          sample_16(0, 0) == 0 && sample_16(1, 0) == 1 &&
+              sample_16(2, 0) == 2 && sample_16(4, 0) == 4 &&
+              sample_16(8, 0) == 64 && sample_16(0, 1) == 8 &&
+              sample_16(0, 2) == 16 && sample_16(0, 4) == 32,
+          "Standard64KB 16-bit mapping interleaved X/Y address bits incorrectly");
   TileConvertLinearToTiledRenderTarget(
       render_target.data(), known.data(), block_width, block_height,
       block_width, sizeof(uint32_t), block_size);