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| author | Ulrich Drepper <drepper@gmail.com> | 2012-01-10 20:52:29 -0500 |
|---|---|---|
| committer | Ulrich Drepper <drepper@gmail.com> | 2012-01-10 20:52:29 -0500 |
| commit | a47a831ad82735bd19cfa1d0b441c1bd62b2a29a (patch) | |
| tree | f5221c57580598d0f8cee080d0848269e80a094a /sysdeps/ieee754/ldbl-96 | |
| parent | 8898f02074fc1c6a461ee19a817b482b9ffca639 (diff) | |
| download | glibc-a47a831ad82735bd19cfa1d0b441c1bd62b2a29a.tar.gz glibc-a47a831ad82735bd19cfa1d0b441c1bd62b2a29a.tar.xz glibc-a47a831ad82735bd19cfa1d0b441c1bd62b2a29a.zip | |
Optimize ldexp and scalbn
Diffstat (limited to 'sysdeps/ieee754/ldbl-96')
| -rw-r--r-- | sysdeps/ieee754/ldbl-96/s_scalbnl.c | 38 |
1 files changed, 13 insertions, 25 deletions
diff --git a/sysdeps/ieee754/ldbl-96/s_scalbnl.c b/sysdeps/ieee754/ldbl-96/s_scalbnl.c index 9f441fd1e9..6a41920aca 100644 --- a/sysdeps/ieee754/ldbl-96/s_scalbnl.c +++ b/sysdeps/ieee754/ldbl-96/s_scalbnl.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 two64 = 1.8446744073709551616e19L, twom64 = 5.421010862427522170037e-20L, huge = 1.0e+4900L, tiny = 1.0e-4900L; -#ifdef __STDC__ - long double __scalbnl (long double x, int n) -#else - long double __scalbnl (x,n) - long double x; int n; -#endif +long double +__scalbnl (long double x, 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 *= two64; GET_LDOUBLE_EXP(hx,x); k = (hx&0x7fff) - 64; } - 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 <= -64) + if (k <= -64) return tiny*__copysignl(tiny,x); /*underflow*/ - k += 64; /* subnormal result */ + k += 64; /* subnormal result */ SET_LDOUBLE_EXP(x,(es&0x8000)|k); - return x*twom64; + return x*twom64; } weak_alias (__scalbnl, scalbnl) |