Why interrupt 0x2A doesn't work in x64?

Question

I ues this code to get system up time :

procedure GetSystemUpTime(var Hour, Minute : integer);

function GetSysTime : dword;
  asm
    int $2a
  end;
begin
  Hour := GetSysTime() div 3600000;
  Minute := GetSysTime() mod 3600000 div 60000;
end;

procedure TForm1.Button1Click(Sender : TObject);
var
  H, M : integer;
begin
  GetSystemUpTime(H, M);
  Label1.Caption := IntToStr(H) + ':' + IntToStr(M);
end;

I test it in win8 x86 and XP x86 it works , but fail in win7 x64 with error:

I wonder how to get system interruption in x64 , can anybody fix it ?

Answer 1

This behavior is not related to the OS processor architecture. The 0x2A interruption gives access to the undocumented function KiGetTickCount, but this only work until Windows XP,starting with windows vista you can use the GetTickCount64 function to get the milliseconds that have elapsed since the system was started, also you can use the Win32_OperatingSystem WMI class and the LastBootUpTime property.

BTW, If you need measure a frame of time minor than 49.7 days, you can use the GetTickCount function.

procedure GetSystemUpTime(var Hour, Minute : integer);
var
 LTicks : DWORD;
begin
  LTicks := GetTickCount();
  Hour   := LTicks div 3600000;
  Minute := LTicks mod 3600000 div 60000;
end;

UPDATE

It seems which the KiGetTickCount function is exposed via the interrupt 0x2A interface only on 32-bit versions of Windows.

This is the result of dump the IDT(Interrupt Descriptor Table) on x86 Windows using the Kernel Debugger.

00: 805421b0 nt!KiTrap00
01: f620a4f6 ati2mtag+0x1774F6
02: Task Selector = 0x0058
03: f620a59c ati2mtag+0x17759C
04: 805428c0 nt!KiTrap04
05: 80542a20 nt!KiTrap05
06: 80542b94 nt!KiTrap06
07: 8054320c nt!KiTrap07
08: Task Selector = 0x0050
09: 80543610 nt!KiTrap09
0a: 80543730 nt!KiTrap0A
0b: 80543870 nt!KiTrap0B
0c: 80543ad0 nt!KiTrap0C
0d: 80543dbc nt!KiTrap0D
0e: 805444b8 nt!KiTrap0E
0f: 805447f0 nt!KiTrap0F
10: 80544910 nt!KiTrap10
11: 80544a4c nt!KiTrap11
12: Task Selector = 0×00A0
13: 80544bb4 nt!KiTrap13
14: 805447f0 nt!KiTrap0F
15: 805447f0 nt!KiTrap0F
16: 805447f0 nt!KiTrap0F
17: 805447f0 nt!KiTrap0F
18: 805447f0 nt!KiTrap0F
19: 805447f0 nt!KiTrap0F
1a: 805447f0 nt!KiTrap0F
1b: 805447f0 nt!KiTrap0F
1c: 805447f0 nt!KiTrap0F
1d: 805447f0 nt!KiTrap0F
1e: 805447f0 nt!KiTrap0F
1f: 806e710c hal!HalpApicSpuriousService
20: 00000000
21: 00000000
22: 00000000
23: 00000000
24: 00000000
25: 00000000
26: 00000000
27: 00000000
28: 00000000
29: 00000000
>>2a: 805419de nt!KiGetTickCount<<
2b: 80541ae0 nt!KiCallbackReturn
2c: 80541c90 nt!KiSetLowWaitHighThread
2d: 8054261c nt!KiDebugService
2e: 80541461 nt!KiSystemService
2f: 805447f0 nt!KiTrap0F
30: 80540b20 nt!KiUnexpectedInterrupt0
31: 80540b2a nt!KiUnexpectedInterrupt1
32: 80540b34 nt!KiUnexpectedInterrupt2
33: 80540b3e nt!KiUnexpectedInterrupt3
34: 80540b48 nt!KiUnexpectedInterrupt4
35: 80540b52 nt!KiUnexpectedInterrupt5
36: 80540b5c nt!KiUnexpectedInterrupt6

and now in x64

00: fffff80001865180 nt!KiDivideErrorFault
01: fffff80001865240 nt!KiDebugTrapOrFault
02: fffff80001865380 nt!KiNmiInterrupt Stack = 0xFFFFFA60005F5D40
03: fffff800018656c0 nt!KiBreakpointTrap
04: fffff80001865780 nt!KiOverflowTrap
05: fffff80001865840 nt!KiBoundFault
06: fffff80001865900 nt!KiInvalidOpcodeFault
07: fffff80001865ac0 nt!KiNpxNotAvailableFault
08: fffff80001865b80 nt!KiDoubleFaultAbort Stack = 0xFFFFFA60005F1D40
09: fffff80001865c40 nt!KiNpxSegmentOverrunAbort
0a: fffff80001865d00 nt!KiInvalidTssFault
0b: fffff80001865dc0 nt!KiSegmentNotPresentFault
0c: fffff80001865ec0 nt!KiStackFault
0d: fffff80001865fc0 nt!KiGeneralProtectionFault
0e: fffff800018660c0 nt!KiPageFault
10: fffff80001866400 nt!KiFloatingErrorFault
11: fffff80001866540 nt!KiAlignmentFault
12: fffff80001866600 nt!KiMcheckAbort Stack = 0xFFFFFA60005F3D40
13: fffff80001866940 nt!KiXmmException
1f: fffff80001895290 nt!KiApcInterrupt
2c: fffff80001866ac0 nt!KiRaiseAssertion
2d: fffff80001866b80 nt!KiDebugServiceTrap
2f: fffff800018aeb60 nt!KiDpcInterrupt