Mega Code Archive
How to get CPU clock frequency
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Title: How to get CPU clock frequency?
Question: This code will return CPU frequency...
Answer:
// returns CPU clock frequency
// intDelayTime: measure time in ms - increase to get a more accuracy return
function CPUClock(const intDelayTime: integer = 500): double;
var
TimerHi, TimerLo: DWORD;
PriorityClass, Priority: Integer;
begin
// saves thread priority for the process
PriorityClass := GetPriorityClass(GetCurrentProcess);
Priority := GetThreadPriority(GetCurrentThread);
// sets priority to REAL-TIME
SetPriorityClass(GetCurrentProcess, REALTIME_PRIORITY_CLASS);
SetThreadPriority(GetCurrentThread, THREAD_PRIORITY_TIME_CRITICAL);
// "delay" for priority effect
Sleep(10);
asm
dw 310Fh // rdtsc
mov TimerLo, eax
mov TimerHi, edx
end;
// waits for calculations
Sleep(intDelayTime);
asm
dw 310Fh // rdtsc
sub eax, TimerLo
sbb edx, TimerHi
mov TimerLo, eax
mov TimerHi, edx
end;
// restores process priority
SetThreadPriority(GetCurrentThread, Priority);
SetPriorityClass(GetCurrentProcess, PriorityClass);
// sets the result with CPU clock frequency
result := TimerLo / (1000.0 * intDelayTime);
end;
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