KeQueryTickCount宏的展开

#define KeQueryTickCount(CurrentCount ) { \
    volatile PKSYSTEM_TIME _TickCount = *((PKSYSTEM_TIME *)(&KeTickCount)); \
    while (TRUE) {                                                          \
        (CurrentCount)->HighPart = _TickCount->High1Time;                   \
        (CurrentCount)->LowPart = _TickCount->LowPart;                      \
        if ((CurrentCount)->HighPart == _TickCount->High2Time) break;       \
        _asm { rep nop }                                                    \
    }                                                                       \
}

 

一下是c语言代码

	LARGE_INTEGER testNumber;
	_asm nop;
	KeQueryTickCount(&testNumber);
	_asm nop;

 

下面是编译的汇编代码

.text:000104C9                 nop
.text:000104CA                 mov     eax, ds:KeTickCount
.text:000104CF                 mov     [ebp+var_18], eax
.text:000104D2
.text:000104D2 loc_104D2:                              ; CODE XREF: DriverEntry+3Bj
.text:000104D2                 mov     ecx, 1
.text:000104D7                 test    ecx, ecx
.text:000104D9                 jz      short loc_104FD
.text:000104DB                 mov     edx, [ebp+var_18]
.text:000104DE                 mov     eax, [edx+4]
.text:000104E1                 mov     [ebp+var_C], eax
.text:000104E4                 mov     ecx, [ebp+var_18]
.text:000104E7                 mov     edx, [ecx]
.text:000104E9                 mov     [ebp+var_10], edx//var_10就是testNumber
.text:000104EC                 mov     eax, [ebp+var_18]
.text:000104EF                 mov     ecx, [ebp+var_C]
.text:000104F2                 cmp     ecx, [eax+8]
.text:000104F5                 jnz     short loc_104F9
.text:000104F7                 jmp     short loc_104FD
.text:000104F9 ; ---------------------------------------------------------------------------
.text:000104F9
.text:000104F9 loc_104F9:                              ; CODE XREF: DriverEntry+35j
.text:000104F9                 pause
.text:000104FB                 jmp     short loc_104D2
.text:000104FD ; ---------------------------------------------------------------------------
.text:000104FD
.text:000104FD loc_104FD:                              ; CODE XREF: DriverEntry+19j
.text:000104FD                                         ; DriverEntry+37j
.text:000104FD                 nop