Section: Linux Programmer's Manual (2)
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vm86old, vm86 - enter virtual 8086 mode
int vm86old(struct vm86_struct *info);
int vm86(unsigned long fn, struct vm86plus_struct *v86);
The system call
was introduced in Linux 0.97p2.
In Linux 2.1.15 and 2.0.28, it was renamed to
and a new
The definition of
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
VM86 mode is an emulation of real mode within a protected mode task.
On success, zero is returned.
On error, -1 is returned, and
is set appropriately.
This return value is specific to i386 and indicates a problem with getting
This return value indicates the call is not implemented on the present
Saved kernel stack exists.
(This is a kernel sanity check; the saved
stack should exist only within vm86 mode itself.)
This call is specific to Linux on 32-bit Intel processors,
and should not be used in programs intended to be portable.
This page is part of release 4.16 of the Linux
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