diff options
| author | vlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4> | 2014-07-07 12:43:59 +0000 |
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| committer | vlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4> | 2014-07-07 12:43:59 +0000 |
| commit | 0042944a05c2bada008edd3f3bccecbedb98b746 (patch) | |
| tree | 41407ff34314f00b2e51e7ed0d5cf4e110562f14 /src/mpfr-impl.h | |
| parent | 8f2321df512efa7b6de2a71f6b48406053aa0671 (diff) | |
| download | mpfr-0042944a05c2bada008edd3f3bccecbedb98b746.tar.gz | |
Added debug of branch prediction / --enable-debug-prediction configure
option (patch from Patrick Pélissier, with some changes).
git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@9141 280ebfd0-de03-0410-8827-d642c229c3f4
Diffstat (limited to 'src/mpfr-impl.h')
| -rw-r--r-- | src/mpfr-impl.h | 48 |
1 files changed, 45 insertions, 3 deletions
diff --git a/src/mpfr-impl.h b/src/mpfr-impl.h index a56754b99..91f53ca74 100644 --- a/src/mpfr-impl.h +++ b/src/mpfr-impl.h @@ -1047,12 +1047,54 @@ typedef union { mp_size_t s; mp_limb_t l; } mpfr_size_limb_t; /* Theses macros help the compiler to determine if a test is likely or unlikely. The !! is necessary in case x is larger than a long. */ -#if __MPFR_GNUC(3,0) || __MPFR_ICC(8,1,0) -# define MPFR_LIKELY(x) (__builtin_expect(!!(x),1)) -# define MPFR_UNLIKELY(x) (__builtin_expect(!!(x),0)) +#if defined MPFR_DEBUG_PREDICTION && __MPFR_GNUC(3,0) + +/* Code to debug branch prediction, based on Ulrich Drepper's paper + * "What Every Programmer Should Know About Memory": + * http://people.freebsd.org/~lstewart/articles/cpumemory.pdf + */ +asm (".section predict_data, \"aw\"; .previous\n" + ".section predict_line, \"a\"; .previous\n" + ".section predict_file, \"a\"; .previous"); +# if defined __x86_64__ +# define MPFR_DEBUGPRED__(e,E) \ + ({ long int _e = !!(e); \ + asm volatile (".pushsection predict_data\n" \ + "..predictcnt%=: .quad 0; .quad 0\n" \ + ".section predict_line; .quad %c1\n" \ + ".section predict_file; .quad %c2; .popsection\n" \ + "addq $1,..predictcnt%=(,%0,8)" \ + : : "r" (_e == E), "i" (__LINE__), "i" (__FILE__)); \ + __builtin_expect (_e, E); \ + }) +# elif defined __i386__ +# define MPFR_DEBUGPRED__(e,E) \ + ({ long int _e = !!(e); \ + asm volatile (".pushsection predict_data\n" \ + "..predictcnt%=: .long 0; .long 0\n" \ + ".section predict_line; .long %c1\n" \ + ".section predict_file; .long %c2; .popsection\n" \ + "incl ..predictcnt%=(,%0,4)" \ + : : "r" (_e == E), "i" (__LINE__), "i" (__FILE__)); \ + __builtin_expect (_e, E); \ + }) +# else +# error "MPFR_DEBUGPRED__ definition missing" +# endif + +# define MPFR_LIKELY(x) MPFR_DEBUGPRED__ ((x), 1) +# define MPFR_UNLIKELY(x) MPFR_DEBUGPRED__ ((x), 0) + +#elif __MPFR_GNUC(3,0) || __MPFR_ICC(8,1,0) + +# define MPFR_LIKELY(x) (__builtin_expect(!!(x), 1)) +# define MPFR_UNLIKELY(x) (__builtin_expect(!!(x), 0)) + #else + # define MPFR_LIKELY(x) (x) # define MPFR_UNLIKELY(x) (x) + #endif /* Declare that some variable is initialized before being used (without a |