********
program VBEPM;
{$X+} (* turn on extended syntax *)
{$G+} (* turn on 286 syntax, needed for "shr bh, 4" *)
uses crt;
const
On = 0;
StandBy = 1;
Suspend = 2;
Off = 4;
ReducedOn = 8; (* for flat screens *)
type
CapsTp = record
Version : word;
StandBySupported,
SuspendSupported,
OffSupported,
ReducedOnSupported : boolean;
end;
function GetCaps(var Caps : CapsTp) : boolean;
(* returns True if VBE/PM is supported *)
const
StandByMask = 1;
SuspendMask = 2;
OffMask = 4;
ReducedOnMask = 8;
var
Result : byte;
SupportedStates : byte;
begin
asm
mov ax, 4f10h (* VBE/PM *)
xor bl, bl (* get capabilities *)
xor di, di
mov es, di
int 10h
mov [SupportedStates], bh
mov bh, bl (* BL = VBE/PM version (bits 7-4: major, bits
3-0: minor) *)
shr bh, 4 (* BH = major version number *)
and bl, 0fh (* BL = minor version number *)
les di, Caps
mov es:[di], bx
xor al, 4fh
or al, ah
mov [Result], al
end;
with Caps do
begin
StandBySupported := (SupportedStates and StandByMask) <> 0;
SuspendSupported := (SupportedStates and SuspendMask) <> 0;
OffSupported := (SupportedStates and OffMask) <> 0;
ReducedOnSupported := (SupportedStates and ReducedOnMask) <> 0;
end;
GetCaps := Result = 0;
end;
function SetDisplayPowerState(State : byte) : boolean;assembler;
(* returns True if VBE/PM is supported *)
asm
mov ax, 4f10h (* VBE/PM *)
mov bl, 1 (* set display power state *)
mov bh, [State]
int 10h
xor al, 4fh
or al, ah
mov al, 0
jnz @Error
inc ax
@Error:
end;
function GetDisplayPowerState(var State : byte) : boolean;assembler;
(* returns True if VBE/PM is supported *)
asm
mov ax, 4f10h (* VBE/PM *)
mov bl, 2 (* set display power state *)
int 10h
les di, State
mov es:[di], bh
xor al, 4fh
or al, ah
mov al, 0
jnz @Error
inc ax
@Error:
end;
var
Caps : CapsTp;
State : byte;
begin
ClrScr;
if not GetCaps(Caps) then
Writeln('VBE/PM not supported')
else
begin
with Caps do
begin
writeln('VBE/PM v',Hi(Caps.Version),'.',Lo(Caps.Version),'
detected');
writeln('Supported:');
writeln(' Standby : ',StandBySupported);
writeln(' Suspend : ',SuspendSupported);
writeln(' Off : ',OffSupported);
writeln(' ReducedOn : ',ReducedOnSupported);
writeln;
if not GetDisplayPowerState(State) then
writeln('Error with getting the power state')
else
writeln('Screen is on : ',State = On);
if StandbySupported then
begin
writeln;
writeln('Press a key to go standby and another press to get
back.');
readkey;
writeln('Standby successful: ',SetDisplayPowerState(StandBy));
readkey;
writeln('On successful : ',SetDisplayPowerState(On));
end;
end;
end;
end.
