1VM86(2)                    Linux Programmer's Manual                   VM86(2)
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NAME

6       vm86old, vm86 - enter virtual 8086 mode
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SYNOPSIS

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

16       The  system call vm86() was introduced in Linux 0.97p2. In Linux 2.1.15
17       and 2.0.28 it was renamed to vm86old(), and a  new  vm86()  was  intro‐
18       duced.  The definition of `struct vm86_struct' was changed in 1.1.8 and
19       1.1.9.
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21       These calls cause the process to enter VM86 mode (virtual-8086 in Intel
22       literature), and are used by dosemu.
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24       VM86 mode is an emulation of real mode within a protected mode task.
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RETURN VALUE

27       On  success,  zero is returned.  On error, -1 is returned, and errno is
28       set appropriately.
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ERRORS

31       EFAULT This return value is specific to i386 and  indicates  a  problem
32              with getting userspace data.
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34       ENOSYS This  return  value indicates the call is not implemented on the
35              present architecture.
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37       EPERM  Saved kernel stack exists. (This is a kernel sanity  check;  the
38              saved stack should only exist within vm86 mode itself.)
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CONFORMING TO

41       This  call  is specific to Linux on Intel processors, and should not be
42       used in programs intended to be portable.
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46Linux 2.1.15                      1997-07-17                           VM86(2)