timercpu.h
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00001 /*
00002  * Copyright (c) 2011, Mårten Björkman (celle@csc.kth.se) 
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions are
00007  * met:
00008  *
00009  *  1.Redistributions of source code must retain the above copyright
00010  *    notice, this list of conditions and the following disclaimer.
00011  *  2.Redistributions in binary form must reproduce the above
00012  *    copyright notice, this list of conditions and the following
00013  *    disclaimer in the documentation and/or other materials provided
00014  *    with the distribution.  
00015  *  3.The name of Mårten Björkman may not be used to endorse or
00016  *    promote products derived from this software without specific
00017  *    prior written permission.
00018  *
00019  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00020  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00021  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00022  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
00023  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
00024  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
00025  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
00026  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
00027  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
00028  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
00029  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00030  */
00031 
00032 #ifndef TIMERCPU_H
00033 #define TIMERCPU_H
00034 
00037 
00038 class TimerCPU
00039 {
00040   static const int bits = 10;
00041 public:
00043   long long beg_clock;
00045   float freq;
00047 
00050   TimerCPU(float freq_) : freq(freq_) {   // freq = clock frequency in MHz
00051     beg_clock = getTSC(bits);
00052   }
00054   long long getTSC(int bits) {
00055     unsigned int low, high;
00056     __asm__(".byte 0x0f, 0x31" :"=a" (low), "=d" (high));
00057     return ((long long)high<<(32-bits)) | ((long long)low>>bits);
00058   }
00059   
00061 
00064   float read() {
00065     long long end_clock = getTSC(bits);
00066     long long Kcycles = end_clock - beg_clock;
00067     float time = (float)(1<<bits)*Kcycles/freq/1e3;
00068     return time;
00069   }
00070 };
00071 
00072 #endif
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fast_plane_detection
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autogenerated on Wed Jan 23 2013 16:52:54