highrestimer.pas

非常精確的 timer 控件 delphi 3.0, 4.0, 5.0, 6.0, 7.0 適用

unit HighResTimer;

{******************************************************************************
*                                                                             *
* THighResTimer Component                                                     *
*                                                                             *
* Component for high resolution time measurement and wait routines.           *
* The component can reach resolution and accuracy of a few micro seconds.     *
* Because Win32 is not a real time operating system the resolution and the    *
* accuracy of this component can't be garuanteed. Setting the execution thread*
* and the component thread to an approbiate priority the resolution and       *
* accuracy will be with in the limits for more than 90% of the calls.         *
* Remarks:                                                                    *
*   For high accuracy of the time stamp counter a calibration should last two *
*   seconds or longer.                                                        *
* Ussage hints:                                                               *
*   For pure time measurement the timer doesn't need to be enabled. At the    *
*   begining test wether the TSC can be used or not.                          *
*   Befor using the Wait function enable the timer. The default calibration   *
*   is fast but not very accurate, so do a custom calibrate if needed.        *
*   After a change of the UseTSC property always a recalibration is needed for*
*   high accuracy. Use TSC can be cahnged only if timer is disabled.          *
*                                                                             *
* If you find any bugs or improvements, please let me know. If you modify the *
* source code, please send me a copy.                                         *
*                                                                             *
* Legal issues:                                                               *
*                                                                             *
* Copyright (C) 2002 by Roman Lauer <[e-mail]>                           *
*                                                                             *
*  This software is provided 'as-is', without any express or implied          *
*  warranty.  In no event will the author be held liable for any damages      *
*  arising from the use of this software.                                     *
*                                                                             *
*  Permission is granted to anyone to use this software for any purpose,      *
*  including commercial applications, and to alter it and redistribute it     *
*  freely, subject to the following restrictions:                             *
*                                                                             *
*  1. The origin of this software must not be misrepresented, you must not    *
*     claim that you wrote the original software. If you use this software    *
*     in a product, an acknowledgment in the product documentation would be   *
*     appreciated but is not required.                                        *
*                                                                             *
*  2. Altered source versions must be plainly marked as such, and must not be *
*     misrepresented as being the original software.                          *
*                                                                             *
*  3. This notice may not be removed or altered from any source distribution. *
*                                                                             *
*  4. These components may not be included in any component package that is   *
*      distributed for profit.                                                *
*                                                                             *
* Credits go to:                                                              *
*  Robert T. Palmqvist: I copy his header for these comments                  *
*  Udo Juerss: I used his TimeStampCounter and put it into this component.    *
*  Autor of Component tacpuid: Used some of his assembler routines.           *
*      (with modifications)                                                   *
*                                                                             *
* Bibliography:                                                               *
*                                                                             *
*   http://www.pergolesi.demon.co.uk/prog/threads/ToC.html                    *
*      Tutorial about multi threading with delphi                             *
*   MSDN                                                                      *
*      Learned about multi media timers.                                      *
*   IA-32 Intel