From 3189a0e259938fc3dbedc16a63a0b860e772dc7d Mon Sep 17 00:00:00 2001
From: Triang3l <triang3l@yandex.ru>
Date: Sun, 12 May 2024 20:26:14 +0300
Subject: [PATCH] [GPU] Check memexport stream constant upper bits in range
 gathering

---
 src/xenia/gpu/draw_util.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/xenia/gpu/draw_util.cc b/src/xenia/gpu/draw_util.cc
index 1b5671fcb..b9f70ef1d 100644
--- a/src/xenia/gpu/draw_util.cc
+++ b/src/xenia/gpu/draw_util.cc
@@ -659,7 +659,14 @@ void AddMemExportRanges(const RegisterFile& regs, const Shader& shader,
   for (uint32_t constant_index : shader.memexport_stream_constants()) {
     xenos::xe_gpu_memexport_stream_t stream =
         regs.GetMemExportStream(float_constants_base + constant_index);
-    if (!stream.index_count) {
+    // Safety checks for stream constants potentially not set up if the export
+    // isn't done on the control flow path taken by the shader (not checking the
+    // Y component because the index is more likely to be constructed
+    // arbitrarily).
+    // The hardware validates the upper bits of eA according to the
+    // IPR2015-00325 sequencer specification.
+    if (stream.const_0x1 != 0x1 || stream.const_0x4b0 != 0x4B0 ||
+        stream.const_0x96 != 0x96 || !stream.index_count) {
       continue;
     }
     const FormatInfo& format_info =