vm86old, vm86 - enter virtual 8086 mode
Standard C library (libc, -lc)
#include <sys/vm86.h>
int vm86old(struct vm86_struct *info);
int vm86(unsigned long fn, struct vm86plus_struct *v86);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.
On success, zero is returned. On error, -1 is returned, and
errno is set to indicate the error.
This return value is specific to i386 and indicates a problem with getting user-space data.
This return value indicates the call is not implemented on the present architecture.
Saved kernel stack exists. (This is a kernel sanity check; the saved stack should exist only within vm86 mode itself.)
Linux on 32-bit Intel processors.