From 3a96083adab9a0c74bd25000ffd5a5d5e81e2081 Mon Sep 17 00:00:00 2001
From: friendlyanon <friendlyanon@users.noreply.github.com>
Date: Wed, 1 May 2024 18:17:50 +0200
Subject: [PATCH] Implement `InterlockedCompareExchange` w/ `__asm`

---
 wrappers/kernel32.c | 43 ++++++++++++++++++++++++-------------------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/wrappers/kernel32.c b/wrappers/kernel32.c
index 25e777f..f3be02f 100644
--- a/wrappers/kernel32.c
+++ b/wrappers/kernel32.c
@@ -154,33 +154,38 @@ BOOL WINAPI CORKEL32_DeviceIoControl(HANDLE hDevice, DWORD dwIoControlCode, LPVO
   return e;
 }
 
-static LONG __declspec(naked) WINAPI InterlockedCompareExchange_486(LONG* dest, LONG xchg, LONG compare)
+static char const* InterlockedCompareExchange_name = "InterlockedCompareExchange";
+
+// Reimplemented
+__declspec(naked) LONG WINAPI CORKEL32_InterlockedCompareExchange(LONG* dest, LONG exchange, LONG compare)
 {
   __asm {
-    mov ecx, DWORD PTR [esp + 4] ; dest
-    mov edx, DWORD PTR [esp + 8] ; xchg
+    cmp has_cmpxchg, 0
+    jz ICE_is_386
+    mov edx, DWORD PTR [esp + 4] ; dest
+    mov ecx, DWORD PTR [esp + 8] ; exchange
     mov eax, DWORD PTR [esp + 12] ; compare
-    lock cmpxchg DWORD PTR [ecx], edx
+    mov ebx, DWORD PTR [edx]
+    lock cmpxchg DWORD PTR [edx], ecx
+    mov eax, ebx
     ret 12
-  }
-}
 
-// Reimplemented
-LONG WINAPI CORKEL32_InterlockedCompareExchange(LONG* dest, LONG xchg, LONG compare)
-{
-  LONG temp;
-  if (has_cmpxchg) {
-    return InterlockedCompareExchange_486(dest, xchg, compare);
-  }
+  ICE_is_386:
+    push InterlockedCompareExchange_name
+    push TRACE_FORCE_DONT_PRINT
+    call Trace
+    add esp, 8
 
-  temp = *dest;
-  Trace(TRACE_FORCE_DONT_PRINT, "InterlockedCompareExchange");
+    mov edx, DWORD PTR [esp + 4] ; dest
+    mov eax, DWORD PTR [edx]
+    cmp DWORD PTR [esp + 12], eax ; compare
+    jne ICE_exit
+    mov ecx, DWORD PTR [esp + 8] ; exchange
+    mov DWORD PTR [edx], ecx
 
-  if (compare == *dest) {
-    *dest = xchg;
+  ICE_exit:
+    ret 12
   }
-
-  return temp;
 }
 
 HANDLE WINAPI CORKEL32_CreateToolhelp32Snapshot(DWORD param_0, DWORD param_1)