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| author | Ulrich Drepper <drepper@gmail.com> | 2011-10-12 11:27:51 -0400 |
|---|---|---|
| committer | Ulrich Drepper <drepper@gmail.com> | 2011-10-12 11:27:51 -0400 |
| commit | 0ac5ae2335292908f39031b1ea9fe8edce433c0f (patch) | |
| tree | f9d26c8abc0de39d18d4c13e70f6022cdc6b461f /sysdeps/ieee754/dbl-64/e_log10.c | |
| parent | a843a204a3e8a0dd53584dad3668771abaec84ac (diff) | |
| download | glibc-0ac5ae2335292908f39031b1ea9fe8edce433c0f.tar.gz | |
Optimize libm
libm is now somewhat integrated with gcc's -ffinite-math-only option
and lots of the wrapper functions have been optimized.
Diffstat (limited to 'sysdeps/ieee754/dbl-64/e_log10.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/e_log10.c | 42 |
1 files changed, 14 insertions, 28 deletions
diff --git a/sysdeps/ieee754/dbl-64/e_log10.c b/sysdeps/ieee754/dbl-64/e_log10.c index e8a3278eaf..6a630bcef7 100644 --- a/sysdeps/ieee754/dbl-64/e_log10.c +++ b/sysdeps/ieee754/dbl-64/e_log10.c @@ -10,10 +10,6 @@ * ==================================================== */ -#if defined(LIBM_SCCS) && !defined(lint) -static char rcsid[] = "$NetBSD: e_log10.c,v 1.9 1995/05/10 20:45:51 jtc Exp $"; -#endif - /* __ieee754_log10(x) * Return the base 10 logarithm of x * @@ -50,28 +46,16 @@ static char rcsid[] = "$NetBSD: e_log10.c,v 1.9 1995/05/10 20:45:51 jtc Exp $"; #include "math.h" #include "math_private.h" -#ifdef __STDC__ static const double -#else -static double -#endif two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */ ivln10 = 4.34294481903251816668e-01, /* 0x3FDBCB7B, 0x1526E50E */ log10_2hi = 3.01029995663611771306e-01, /* 0x3FD34413, 0x509F6000 */ log10_2lo = 3.69423907715893078616e-13; /* 0x3D59FEF3, 0x11F12B36 */ -#ifdef __STDC__ static const double zero = 0.0; -#else -static double zero = 0.0; -#endif -#ifdef __STDC__ - double __ieee754_log10(double x) -#else - double __ieee754_log10(x) - double x; -#endif +double +__ieee754_log10(double x) { double y,z; int32_t i,k,hx; @@ -79,20 +63,22 @@ static double zero = 0.0; EXTRACT_WORDS(hx,lx,x); - k=0; - if (hx < 0x00100000) { /* x < 2**-1022 */ - if (((hx&0x7fffffff)|lx)==0) - return -two54/(x-x); /* log(+-0)=-inf */ - if (hx<0) return (x-x)/(x-x); /* log(-#) = NaN */ - k -= 54; x *= two54; /* subnormal number, scale up x */ + k=0; + if (hx < 0x00100000) { /* x < 2**-1022 */ + if (__builtin_expect(((hx&0x7fffffff)|lx)==0, 0)) + return -two54/(x-x); /* log(+-0)=-inf */ + if (__builtin_expect(hx<0, 0)) + return (x-x)/(x-x); /* log(-#) = NaN */ + k -= 54; x *= two54; /* subnormal number, scale up x */ GET_HIGH_WORD(hx,x); - } - if (hx >= 0x7ff00000) return x+x; + } + if (__builtin_expect(hx >= 0x7ff00000, 0)) return x+x; k += (hx>>20)-1023; i = ((u_int32_t)k&0x80000000)>>31; - hx = (hx&0x000fffff)|((0x3ff-i)<<20); - y = (double)(k+i); + hx = (hx&0x000fffff)|((0x3ff-i)<<20); + y = (double)(k+i); SET_HIGH_WORD(x,hx); z = y*log10_2lo + ivln10*__ieee754_log(x); return z+y*log10_2hi; } +strong_alias (__ieee754_log10, __log10_finite) |