vm86old, vm86 - enter virtual 8086 mode
int vm86old(struct vm86_struct *info);
int vm86(unsigned long fn, struct vm86plus_struct
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
introduced. The definition of struct vm86_struct
was changed in 1.1.8
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
- 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.)
This call is specific to Linux on 32-bit Intel processors, and should not be
used in programs intended to be portable.
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