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| author | Ulrich Drepper <drepper@gmail.com> | 2012-01-11 12:49:16 -0500 |
|---|---|---|
| committer | Ulrich Drepper <drepper@gmail.com> | 2012-01-11 12:49:16 -0500 |
| commit | 41d0e8696f370d625390da356d95cab174c7990e (patch) | |
| tree | 545ebdab16006b67c7a2156f8c5f7d0ceee139e1 /sysdeps/ieee754/ldbl-96 | |
| parent | 5452bffeefe076a12eeb04f784ef1209a4282038 (diff) | |
| download | glibc-41d0e8696f370d625390da356d95cab174c7990e.tar.gz | |
Optimize scalbln
Diffstat (limited to 'sysdeps/ieee754/ldbl-96')
| -rw-r--r-- | sysdeps/ieee754/ldbl-96/s_scalblnl.c | 38 |
1 files changed, 13 insertions, 25 deletions
diff --git a/sysdeps/ieee754/ldbl-96/s_scalblnl.c b/sysdeps/ieee754/ldbl-96/s_scalblnl.c index 8e556fabe1..ada587b9d5 100644 --- a/sysdeps/ieee754/ldbl-96/s_scalblnl.c +++ b/sysdeps/ieee754/ldbl-96/s_scalblnl.c @@ -14,10 +14,6 @@ * ==================================================== */ -#if defined(LIBM_SCCS) && !defined(lint) -static char rcsid[] = "$NetBSD: $"; -#endif - /* * scalbnl (long double x, int n) * scalbnl(x,n) returns x* 2**n computed by exponent @@ -28,44 +24,36 @@ static char rcsid[] = "$NetBSD: $"; #include "math.h" #include "math_private.h" -#ifdef __STDC__ static const long double -#else -static long double -#endif two63 = 4.50359962737049600000e+15, twom63 = 1.08420217248550443400e-19, huge = 1.0e+4900L, tiny = 1.0e-4900L; -#ifdef __STDC__ - long double __scalblnl (long double x, long int n) -#else - long double __scalblnl (x,n) - long double x; long int n; -#endif +long double +__scalblnl (long double x, long int n) { int32_t k,es,hx,lx; GET_LDOUBLE_WORDS(es,hx,lx,x); - k = es&0x7fff; /* extract exponent */ - if (k==0) { /* 0 or subnormal x */ - if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */ + k = es&0x7fff; /* extract exponent */ + if (__builtin_expect(k==0, 0)) { /* 0 or subnormal x */ + if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */ x *= two63; GET_LDOUBLE_EXP(es,x); k = (hx&0x7fff) - 63; } - if (k==0x7fff) return x+x; /* NaN or Inf */ - k = k+n; - if (n> 50000 || k > 0x7ffe) + if (__builtin_expect(k==0x7fff, 0)) return x+x; /* NaN or Inf */ + k = k+n; + if (__builtin_expect(n> 50000 || k > 0x7ffe, 0)) return huge*__copysignl(huge,x); /* overflow */ - if (n< -50000) + if (__builtin_expect(n< -50000, 0)) return tiny*__copysignl(tiny,x); - if (k > 0) /* normal result */ + if (__builtin_expect(k > 0, 1)) /* normal result */ {SET_LDOUBLE_EXP(x,(es&0x8000)|k); return x;} - if (k <= -63) + if (k <= -63) return tiny*__copysignl(tiny,x); /*underflow*/ - k += 63; /* subnormal result */ + k += 63; /* subnormal result */ SET_LDOUBLE_EXP(x,(es&0x8000)|k); - return x*twom63; + return x*twom63; } weak_alias (__scalblnl, scalblnl) |