From 621960258d45f75c655d606303c8ae7f34352757 Mon Sep 17 00:00:00 2001
From: ergo720 <45463469+ergo720@users.noreply.github.com>
Date: Wed, 14 Oct 2020 21:34:24 +0200
Subject: [PATCH] Fix crash in Stranger's Wrath caused by false rdtsc positives

---
 src/core/kernel/init/CxbxKrnl.cpp | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/src/core/kernel/init/CxbxKrnl.cpp b/src/core/kernel/init/CxbxKrnl.cpp
index 1ce9cdf25..fe919d90d 100644
--- a/src/core/kernel/init/CxbxKrnl.cpp
+++ b/src/core/kernel/init/CxbxKrnl.cpp
@@ -458,9 +458,9 @@ void PatchRdtsc(xbox::addr_xt addr)
 }
 
 const uint8_t rdtsc_pattern[] = {
-	0x89,//{ 0x0F,0x31,0x89 },
+	0x89,//{ 0x0F,0x31,0x89 },   // two false positives in Stranger's Wrath
 	0xC3,//{ 0x0F,0x31,0xC3 },
-	0x8B,//{ 0x0F,0x31,0x8B },   //one false positive in Sonic Rider .text 88 5C 0F 31
+	0x8B,//{ 0x0F,0x31,0x8B },   // one false positive in Sonic Rider .text 88 5C 0F 31, two false positives in Stranger's Wrath
 	0xB9,//{ 0x0F,0x31,0xB9 },
 	0xC7,//{ 0x0F,0x31,0xC7 },
 	0x8D,//{ 0x0F,0x31,0x8D },
@@ -479,7 +479,7 @@ const uint8_t rdtsc_pattern[] = {
 	0x85,//{ 0x0F,0x31,0x85 },
 	0x83,//{ 0x0F,0x31,0x83 },
 	0x33,//{ 0x0F,0x31,0x33 },
-	0xF7,//{ 0x0F,0x31,0xF7 },
+	0xF7,//{ 0x0F,0x31,0xF7 }, // one false positive in Stranger's Wrath
 	0x8A,//{ 0x0F,0x31,0x8A }, // 8A and 56 only apears in RalliSport 2 .text , need to watch whether any future false positive.
 	0x56,//{ 0x0F,0x31,0x56 }
     0x6A,                      // 6A, 39, EB, F6, A1, 01 only appear in Unreal Championship, 01 is at WMVDEC section
@@ -537,6 +537,20 @@ void PatchRdtscInstructions()
 								continue;
 							}
 
+							if (*(uint8_t *)(addr - 2) == 0x24 && *(uint8_t *)(addr - 1) == 0x0C)
+							{
+								EmuLogInit(LOG_LEVEL::INFO, "Skipped false positive: rdtsc pattern  0x%.2X, @ 0x%.8X", next_byte, (DWORD)addr);
+								continue;
+							}
+						}
+						if (next_byte == 0x89)
+						{
+							if (*(uint8_t *)(addr - 2) == 0x24 && *(uint8_t *)(addr - 1) == 0x04)
+							{
+								EmuLogInit(LOG_LEVEL::INFO, "Skipped false positive: rdtsc pattern  0x%.2X, @ 0x%.8X", next_byte, (DWORD)addr);
+								continue;
+							}
+
 						}
 						if (next_byte == 0x50)
 						{
@@ -555,6 +569,15 @@ void PatchRdtscInstructions()
 								continue;
 							}
 
+						}
+						if (next_byte == 0xF7)
+						{
+							if (*(uint8_t *)(addr - 1) == 0xE8 && *(uint8_t *)(addr + 3) == 0xFF)
+							{
+								EmuLogInit(LOG_LEVEL::INFO, "Skipped false positive: rdtsc pattern  0x%.2X, @ 0x%.8X", next_byte, (DWORD)addr);
+								continue;
+							}
+
 						}
 						PatchRdtsc(addr);
 						//the first for loop already increment addr per loop. we only increment one more time so the addr will point to the byte next to the found rdtsc instruction. this is important since there is at least one case that two rdtsc instructions are next to each other.