Source code of Windows XP (NT5)
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

109 lines
2.4 KiB

//+-------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1992 - 1993.
//
// File: clstub16.cxx
//
// Contents: 32->16 bit call forwarding stub
//
// History: 25-Feb-93 DrewB Created
//
//--------------------------------------------------------------------------
#include <headers.cxx>
#pragma hdrstop
//+---------------------------------------------------------------------------
//
// Function: CallStub16, public
//
// Synopsis: Invokes a 16-bit routine on behalf of the 32-bit code
//
// Arguments: [pcd] - Data describing the call to be made
//
// Returns: Appropriate status code
//
// History: 18-Feb-94 DrewB Created
//
//----------------------------------------------------------------------------
DWORD __loadds FAR PASCAL CallStub16(LPCALLDATA pcd)
{
DWORD dwRes;
DWORD pfn;
WORD cbStack;
DWORD pvStack;
thkAssert(pcd != NULL);
pfn = pcd->vpfn;
cbStack = (WORD)pcd->cbStack;
pvStack = pcd->vpvStack16;
thkDebugOut((DEB_ITRACE, "In CallStub16(%08lX, %u, %08lX)\n",
pfn, cbStack, pvStack));
// Check for wildly out-of-range stack sizes
thkAssert(cbStack < 0x100);
// Make sure that the stack size is even to
// maintain alignment and allow free use of movsw
thkAssert((cbStack & 1) == 0);
__asm
{
// Make space on the real stack for the stack given to us from 32-bits
sub sp, cbStack
// Simple sanity checks on new stack pointer
jc StackOverflow
cmp sp, 512
jb StackOverflow
// Copy pvStack to the real stack
push ds
push si
push es
push di
mov ds, WORD PTR pvStack+2
mov si, WORD PTR pvStack
mov ax, ss
mov es, ax
mov di, sp
// Skip over saved registers
add di, 8
mov cx, cbStack
shr cx, 1
cld
rep movsw
pop di
pop es
pop si
pop ds
// Call the routine
call DWORD PTR pfn
jmp End
StackOverflow:
// E_OUTOFMEMORY
mov dx, 8000h
mov ax, 0002h
End:
mov WORD PTR dwRes, ax
mov WORD PTR dwRes+2, dx
add sp, cbStack
}
thkDebugOut((DEB_ITRACE, "Out CallStub16: return %ld\n",dwRes));
return dwRes;
}