Name

vm86old, vm86 — enter virtual 8086 mode

Synopsis

#include <sys/vm86.h>
int vm86old( struct vm86_struct *info);
 
int vm86( unsigned long fn,
  struct vm86plus_struct *v86);
 

DESCRIPTION

The system call vm86() was introduced in Linux 0.97p2. In Linux 2.1.15 and 2.0.28 it was renamed to vm86old(), and a new vm86() was introduced. The definition of struct vm86_struct was changed in 1.1.8 and 1.1.9.

These calls cause the process to enter VM86 mode (virtual-8086 in Intel literature), and are used by dosemu.

VM86 mode is an emulation of real mode within a protected mode task.

RETURN VALUE

On success, zero is returned. On error, −1 is returned, and errno is set appropriately.

ERRORS

EFAULT

This return value is specific to i386 and indicates a problem with getting userspace data.

ENOSYS

This return value indicates the call is not implemented on the present architecture.

EPERM

Saved kernel stack exists. (This is a kernel sanity check; the saved stack should only exist within vm86 mode itself.)

CONFORMING TO

This call is specific to Linux on 32-bit Intel processors, and should not be used in programs intended to be portable.

COLOPHON

This page is part of release 3.24 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


Copyright 1993 Rickard E. Faith (faithcs.unc.edu)
Copyright 1997 Andries E. Brouwer (aebcwi.nl)

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