c3-lang/libffi

diff --git a/src/x86/win32.S b/src/x86/win32.S
index 699ea46..daf0e79 100644
--- a/src/x86/win32.S
+++ b/src/x86/win32.S
@@ -201,6 +201,15 @@ ffi_closure_THISCALL PROC NEAR
 	jmp	ffi_closure_STDCALL
 ffi_closure_THISCALL ENDP
 
+ffi_closure_FASTCALL PROC NEAR
+	;; Insert the register argument on the stack as the first argument
+	xchg	DWORD PTR [esp+4], edx
+	xchg	DWORD PTR [esp], ecx
+	push	edx
+	push	ecx
+	jmp	ffi_closure_STDCALL
+ffi_closure_FASTCALL ENDP
+
 ffi_closure_SYSV PROC NEAR FORCEFRAME
     ;; the ffi_closure ctx is passed in eax by the trampoline.