1 ;****************************************************************************
3 ;* SciTech OS Portability Manager Library
5 ;* ========================================================================
7 ;* The contents of this file are subject to the SciTech MGL Public
8 ;* License Version 1.0 (the "License"); you may not use this file
9 ;* except in compliance with the License. You may obtain a copy of
10 ;* the License at http://www.scitechsoft.com/mgl-license.txt
12 ;* Software distributed under the License is distributed on an
13 ;* "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
14 ;* implied. See the License for the specific language governing
15 ;* rights and limitations under the License.
17 ;* The Original Code is Copyright (C) 1991-1998 SciTech Software, Inc.
19 ;* The Initial Developer of the Original Code is SciTech Software, Inc.
20 ;* All Rights Reserved.
22 ;* ========================================================================
24 ;* Language: 80386 Assembler, TASM 4.0 or NASM
27 ;* Description: Low level assembly support for the PM library specific
30 ;****************************************************************************
34 include "scitech.mac" ; Memory model macros
36 header _pmwin32 ; Set up memory model
42 _PM_ioentry dd 0 ; Offset to call gate
43 _PM_gdt dw 0 ; Selector to call gate
47 begcodeseg _pmwin32 ; Start of code segment
49 ;----------------------------------------------------------------------------
50 ; int PM_setIOPL(int iopl)
51 ;----------------------------------------------------------------------------
52 ; Change the IOPL level for the 32-bit task. Returns the previous level
53 ; so it can be restored for the task correctly.
54 ;----------------------------------------------------------------------------
55 cprocstart _PM_setIOPLViaCallGate
60 pushfd ; Save the old EFLAGS for later
61 mov ecx,[iopl] ; ECX := IOPL level
62 xor ebx,ebx ; Change IOPL level function code
64 call far dword [_PM_ioentry]
66 call [FWORD _PM_ioentry]
69 and eax,0011000000000000b