os_timer.cpp

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00001 /* $Id: os_timer.cpp 10778 2007-08-03 23:26:12Z truelight $ */
00002 
00005 #include "stdafx.h"
00006 
00007 #undef RDTSC_AVAILABLE
00008 
00009 /* rdtsc for MSC_VER, uses simple inline assembly, or _rdtsc
00010  * from external win64.asm because VS2005 does not support inline assembly */
00011 #if defined(_MSC_VER) && !defined(RDTSC_AVAILABLE) && !defined(WINCE)
00012 # if _MSC_VER >= 1400
00013 #include <intrin.h>
00014 uint64 _rdtsc()
00015 {
00016   return __rdtsc();
00017 }
00018 # else
00019 uint64 _declspec(naked) _rdtsc()
00020 {
00021   _asm {
00022     rdtsc
00023     ret
00024   }
00025 }
00026 # endif
00027 # define RDTSC_AVAILABLE
00028 #endif
00029 
00030 /* rdtsc for OS/2. Hopefully this works, who knows */
00031 #if defined (__WATCOMC__) && !defined(RDTSC_AVAILABLE)
00032 unsigned __int64 _rdtsc();
00033 # pragma aux _rdtsc = 0x0F 0x31 value [edx eax] parm nomemory modify exact [edx eax] nomemory;
00034 # define RDTSC_AVAILABLE
00035 #endif
00036 
00037 /* rdtsc for all other *nix-en (hopefully). Use GCC syntax */
00038 #if defined(__i386__) || defined(__x86_64__) && !defined(RDTSC_AVAILABLE)
00039 uint64 _rdtsc()
00040 {
00041   uint32 high, low;
00042   __asm__ __volatile__ ("rdtsc" : "=a" (low), "=d" (high));
00043   return ((uint64)high << 32) | low;
00044 }
00045 # define RDTSC_AVAILABLE
00046 #endif
00047 
00048 /* rdtsc for PPC which has this not */
00049 #if (defined(__POWERPC__) || defined(__powerpc__)) && !defined(RDTSC_AVAILABLE)
00050 uint64 _rdtsc()
00051 {
00052   uint32 high = 0, high2 = 0, low;
00053   /* PPC does not have rdtsc, so we cheat by reading the two 32-bit time-counters
00054    * it has, 'Move From Time Base (Upper)'. Since these are two reads, in the
00055    * very unlikely event that the lower part overflows to the upper part while we
00056    * read it; we double-check and reread the registers */
00057   asm volatile (
00058           "mftbu %0\n"
00059           "mftb %1\n"
00060           "mftbu %2\n"
00061           "cmpw %3,%4\n"
00062           "bne- $-16\n"
00063           : "=r" (high), "=r" (low), "=r" (high2)
00064           : "0" (high), "2" (high2)
00065           );
00066   return ((uint64)high << 32) | low;
00067 }
00068 # define RDTSC_AVAILABLE
00069 #endif
00070 
00071 /* In all other cases we have no support for rdtsc. No major issue,
00072  * you just won't be able to profile your code with TIC()/TOC() */
00073 #if !defined(RDTSC_AVAILABLE)
00074 /* MSVC (in case of WinCE) can't handle #warning */
00075 # if !defined(_MSC_VER)
00076 #warning "(non-fatal) No support for rdtsc(), you won't be able to profile with TIC/TOC"
00077 # endif
00078 uint64 _rdtsc() {return 0;}
00079 #endif

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