os_timer.cpp

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00001 /* $Id: os_timer.cpp 17248 2009-08-21 20:21:05Z rubidium $ */
00002 
00003 /*
00004  * This file is part of OpenTTD.
00005  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
00006  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
00008  */
00009 
00012 #include "stdafx.h"
00013 
00014 #undef RDTSC_AVAILABLE
00015 
00016 /* rdtsc for MSC_VER, uses simple inline assembly, or _rdtsc
00017  * from external win64.asm because VS2005 does not support inline assembly */
00018 #if defined(_MSC_VER) && !defined(RDTSC_AVAILABLE) && !defined(WINCE)
00019 #include <intrin.h>
00020 uint64 ottd_rdtsc()
00021 {
00022   return __rdtsc();
00023 }
00024 #define RDTSC_AVAILABLE
00025 #endif
00026 
00027 /* rdtsc for OS/2. Hopefully this works, who knows */
00028 #if defined (__WATCOMC__) && !defined(RDTSC_AVAILABLE)
00029 unsigned __int64 ottd_rdtsc();
00030 # pragma aux ottd_rdtsc = 0x0F 0x31 value [edx eax] parm nomemory modify exact [edx eax] nomemory;
00031 # define RDTSC_AVAILABLE
00032 #endif
00033 
00034 /* rdtsc for all other *nix-en (hopefully). Use GCC syntax */
00035 #if (defined(__i386__) || defined(__x86_64__)) && !defined(__DJGPP__) && !defined(RDTSC_AVAILABLE)
00036 uint64 ottd_rdtsc()
00037 {
00038   uint32 high, low;
00039   __asm__ __volatile__ ("rdtsc" : "=a" (low), "=d" (high));
00040   return ((uint64)high << 32) | low;
00041 }
00042 # define RDTSC_AVAILABLE
00043 #endif
00044 
00045 /* rdtsc for PPC which has this not */
00046 #if (defined(__POWERPC__) || defined(__powerpc__)) && !defined(RDTSC_AVAILABLE)
00047 uint64 ottd_rdtsc()
00048 {
00049   uint32 high = 0, high2 = 0, low;
00050   /* PPC does not have rdtsc, so we cheat by reading the two 32-bit time-counters
00051    * it has, 'Move From Time Base (Upper)'. Since these are two reads, in the
00052    * very unlikely event that the lower part overflows to the upper part while we
00053    * read it; we double-check and reread the registers */
00054   asm volatile (
00055           "mftbu %0\n"
00056           "mftb %1\n"
00057           "mftbu %2\n"
00058           "cmpw %3,%4\n"
00059           "bne- $-16\n"
00060           : "=r" (high), "=r" (low), "=r" (high2)
00061           : "0" (high), "2" (high2)
00062           );
00063   return ((uint64)high << 32) | low;
00064 }
00065 # define RDTSC_AVAILABLE
00066 #endif
00067 
00068 /* In all other cases we have no support for rdtsc. No major issue,
00069  * you just won't be able to profile your code with TIC()/TOC() */
00070 #if !defined(RDTSC_AVAILABLE)
00071 /* MSVC (in case of WinCE) can't handle #warning */
00072 # if !defined(_MSC_VER)
00073 #warning "(non-fatal) No support for rdtsc(), you won't be able to profile with TIC/TOC"
00074 # endif
00075 uint64 ottd_rdtsc() {return 0;}
00076 #endif

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