1 .\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
2 .\" Copyright 1997 Andries E. Brouwer (aeb@cwi.nl)
4 .\" %%%LICENSE_START(VERBATIM)
5 .\" Permission is granted to make and distribute verbatim copies of this
6 .\" manual provided the copyright notice and this permission notice are
7 .\" preserved on all copies.
9 .\" Permission is granted to copy and distribute modified versions of this
10 .\" manual under the conditions for verbatim copying, provided that the
11 .\" entire resulting derived work is distributed under the terms of a
12 .\" permission notice identical to this one.
14 .\" Since the Linux kernel and libraries are constantly changing, this
15 .\" manual page may be incorrect or out-of-date. The author(s) assume no
16 .\" responsibility for errors or omissions, or for damages resulting from
17 .\" the use of the information contained herein. The author(s) may not
18 .\" have taken the same level of care in the production of this manual,
19 .\" which is licensed free of charge, as they might when working
22 .\" Formatted or processed versions of this manual, if unaccompanied by
23 .\" the source, must acknowledge the copyright and authors of this work.
26 .TH VM86 2 2021-03-22 "Linux" "Linux Programmer's Manual"
28 vm86old, vm86 \- enter virtual 8086 mode
31 .B #include <sys/vm86.h>
33 .BI "int vm86old(struct vm86_struct *" info );
34 .BI "int vm86(unsigned long " fn ", struct vm86plus_struct *" v86 );
39 was introduced in Linux 0.97p2.
40 In Linux 2.1.15 and 2.0.28, it was renamed to
46 .IR "struct vm86_struct"
50 These calls cause the process to enter VM86 mode (virtual-8086 in Intel
51 literature), and are used by
54 VM86 mode is an emulation of real mode within a protected mode task.
56 On success, zero is returned.
57 On error, \-1 is returned, and
59 is set to indicate the error.
63 This return value is specific to i386 and indicates a problem with getting
67 This return value indicates the call is not implemented on the present
71 Saved kernel stack exists.
72 (This is a kernel sanity check; the saved
73 stack should exist only within vm86 mode itself.)
75 This call is specific to Linux on 32-bit Intel processors,
76 and should not be used in programs intended to be portable.