From 69507b24075eb0882d48aeb93c588da6151ddb1d Mon Sep 17 00:00:00 2001
From: Joachim Henze <Joachim.Henze@reactos.org>
Date: Fri, 2 Dec 2022 23:51:30 +0100
Subject: [PATCH] [0.4.13][RPCRT4] Sync msvc.S with WINE's inline assembly,

as suggested by Thomas

It fixes
CORE-18505 '[MSVC only] VBox 2.0.0 is not able to open, but on GCC it can'

It regressed by:
0.4.12-dev-555-g b6fdb56b9adf780902cc9cf65af1f76365a96ce4 and
0.4.12-dev-544-g 5db885cae7050f46999387ffd88ea6b8a1d512be

Fix picked from 0.4.15-dev-5461-g 062a8f20a9fae1f4962886b582d77c04943dc0c4

The fix works also for MSVC2010SP1 dbg builds in the older branches.
I will not create a new GCC iso for that revision, because this commit does not
affect GCC at all.
---
 dll/win32/rpcrt4/msvc.S | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/dll/win32/rpcrt4/msvc.S b/dll/win32/rpcrt4/msvc.S
index c45ccc68853..41494e6b848 100644
--- a/dll/win32/rpcrt4/msvc.S
+++ b/dll/win32/rpcrt4/msvc.S
@@ -9,24 +9,25 @@ EXTERN _ndr_client_call:PROC
 PUBLIC _call_stubless_func
 _call_stubless_func:
 
-    mov ecx,[esp+4]        /* This Pointer */
-    mov ecx,[ecx]          /* This->lpVtbl */
-    mov ecx,[ecx-8]        /* MIDL_STUBLESS_PROXY_INFO */
-    mov edx,[ecx+8]        /* Info->FormatStringOffset */
-    mov edx,[edx+eax*2]    /* FormatStringOffset[index] */
-    and edx, 0000FFFFh
-    add edx,[ecx+4]        /* info->ProcFormatString + offset */
-    mov eax, [edx+8]       /* arguments size */
-    and eax, 0000FFFFh
+    mov ecx, [esp+4]                /* This Pointer */
+    mov ecx, [ecx]                  /* This->lpVtbl */
+    mov ecx, [ecx-8]                /* MIDL_STUBLESS_PROXY_INFO */
+    mov edx, [ecx+8]                /* Info->FormatStringOffset */
+    movzx edx, word ptr [edx+eax*2] /* FormatStringOffset[index] */
+    add edx, [ecx+4]                /* info->ProcFormatString + offset */
+    movzx eax, byte ptr [edx+1]     /* Oi_flags */
+    and eax, 8                      /* Oi_HAS_RPCFLAGS */
+    shr eax, 1
+    movzx eax, word ptr [edx+eax+4] /* arguments size */
     push eax
-    lea eax, [esp+8]       /* &This */
+    lea eax, [esp+8]                /* &This */
     push eax
-    push edx               /* format string */
-    push [ecx]             /* info->pstubdesc */
+    push edx                        /* format string */
+    push [ecx]                      /* info->pstubdesc */
     call _ndr_client_call
     lea esp, [esp+12]
-    pop edx                /* arguments size */
-    mov ecx, [esp]         /* return address */
+    pop edx                         /* arguments size */
+    mov ecx, [esp]                  /* return address */
     add esp, edx
     jmp ecx
 #else