1 /* 2 * cycles.h - measures CPU cycles using architecture specific extensions. 3 * 4 * Currently only setup for the pentuim using the RDTSC instruction 5 * 6 * Copyright (c) 1998 Phil Maker <pjm@gnu.org> 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * $Id: cycles.h,v 1.1.1.1 1999/09/12 03:26:50 pjm Exp $ 31 */ 32 33 #ifndef _cycles_h_ 34 #define _cycles_h_ 1 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif 39 40 #include <nana-config.h> 41 42 #if HAVE_CYCLES 43 44 #if HAVE_RDTSC /* enabled by configure --enable-rdtsc instruction */ 45 46 /* 47 * Pentium RDTSC instruction - 48 * 49 * 0. 64 bit counter running at clock speed so 50 * (2^64)/(1000*1000*1000*60*60*24*365) = 584 years @ 1GHz 51 * 1. reset to 0 on power on (is it) 52 * 2. on pentium or later CPUs 53 */ 54 55 typedef unsigned long long CYCLES; 56 57 #define cycles() \ 58 ({ \ 59 CYCLES __t; \ 60 asm volatile ("rdtsc ; movl %%edx,%1; movl %%eax,%0" \ 61 : "=m" (__t), "=m" (*(((char *)&__t) + 4)) \ 62 : /* no input */ \ 63 : "eax", "edx", "cc", "memory" \ 64 ); \ 65 __t; \ 66 }) 67 68 #endif /* HAVE_RDTSC */ 69 70 /* 71 * Calibration routines which should be available for all platforms 72 * 73 * cycles_per_second(t,n) - performs n measurements using a spin loop 74 * using the now() function to wait for t or more seconds. It returns 75 * the max number of cycles per second that it measures. As a side 76 * effect (gasp) it also sets the values return by cycles_per_second_min() 77 * and cycles_per_second_max(). 78 * 79 * Notes: 80 * 81 * 1. each call to cycles_per_second() resets our min/max values. 82 * 2. overflows are always possible if t gets too large. 83 * 84 */ 85 86 CYCLES cycles_per_second(double t, int n); 87 CYCLES cycles_per_second_min(); 88 CYCLES cycles_per_second_max(); 89 90 /* 91 * cycles_diff - returns the time in second between two cycle measurement 92 * 93 * Note: start <= stop 94 * stop - start should be representable in a double. 95 * !No overflow detection 96 */ 97 98 double cycles_diff(CYCLES start, CYCLES stop); 99 100 #endif /* HAVE_CYCLES */ 101 #ifdef _cplusplus 102 }; 103 #endif 104 105 #endif /* _cycles_h_ */ 106 107