Value
|
Meaning
|
0001h
|
Invalid VM ID
|
0002h
|
Invalid priority boost
|
0003h
|
Invalid flags
|
Windows calls the callback function as soon as the conditions specified by the Flags parameter are met. This may be before or after Switch VMs and CallBack returns.
The callback function can carry out any action, but must save and restore all registers it modifies. The function must execute an iret instruction to return to Windows. The priority for the virtual machine remains at the level specified by Priority until the callback function executes the iret instruction.
See also Interrupt 2Fh Function 1605h Windows Initialization Notification
Interrupt 2Fh Function 1686h
mov ax, 1686h ; Detect Interrupt 31h Services
int 2Fh ; multiplex interrupt
or ax,0
jz int31_avail ; ax is zero if interrupt 31h services available
Detect Interrupt 31h Services (Interrupt 2Fh Function 1686h) determines whether a set of protected-mode functions are available for use by protected-mode applications. Applications use the Interrupt 31h services to allocate and manage protected-mode memory.
This function has no parameters.
The return value is zero in the AX register if the Interrupt 31h services are available. Otherwise, the AX register contains a nonzero value.
Both standard- and Windows support the Interrupt 31h services. Interrupt 31h services are only supported for protected-mode programs.
Interrupt 2Fh Function 4000h
mov ax, 4000h ; Enable VM-Assisted Save/Restore
int 2fh
mov [ModesSupported], al ; video modes supported while in background
Enable VM-Assisted Save/Restore directs the virtual-display device (VDD) to notify the virtual machine (VM) application whenever the VDD needs to access the video hardware registers. The VDD returns a value specifying the number and type of video modes the VDD supports when the VM application is in the background.
A VM application calls this function during its initialization.
This function has no parameters.
The return value is one of the following values, if successful.
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