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| -rw-r--r-- | ChangeLog | 2 | ||||
| -rw-r--r-- | sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c | 68 |
2 files changed, 70 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index e7ce260758..171e0c238d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,7 @@ 2009-08-25 Ulrich Drepper <drepper@redhat.com> + * sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c: New file. + * sysdeps/x86_64/fpu/s_signbit.S: New file. * sysdeps/x86_64/fpu/s_signbitf.S: New file. diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c new file mode 100644 index 0000000000..25b283f288 --- /dev/null +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c @@ -0,0 +1,68 @@ +/* @(#)s_scalbn.c 5.1 93/09/24 */ +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunPro, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +/* + * scalbn (double x, int n) + * scalbn(x,n) returns x* 2**n computed by exponent + * manipulation rather than by actually performing an + * exponentiation or a multiplication. + */ + +#include "math.h" +#include "math_private.h" + +#ifdef __STDC__ +static const double +#else +static double +#endif +two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */ +twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */ +huge = 1.0e+300, +tiny = 1.0e-300; + +#ifdef __STDC__ + double __scalbln (double x, long int n) +#else + double __scalbln (x,n) + double x; long int n; +#endif +{ + int64_t ix; + int64_t k; + EXTRACT_WORDS64(ix,x); + k = (ix >> 52) & 0x7ff; /* extract exponent */ + if (k==0) { /* 0 or subnormal x */ + if ((ix & UINT64_C(0xfffffffffffff))==0) return x; /* +-0 */ + x *= two54; + EXTRACT_WORDS64(ix,x); + k = ((ix >> 52) & 0x7ff) - 54; + } + if (k==0x7ff) return x+x; /* NaN or Inf */ + k = k+n; + if (n> 50000 || k > 0x7fe) + return huge*__copysign(huge,x); /* overflow */ + if (n< -50000) return tiny*__copysign(tiny,x); /*underflow*/ + if (k > 0) /* normal result */ + {INSERT_WORDS64(x,(ix&UINT64_C(0x800fffffffffffff))|(k<<52)); + return x;} + if (k <= -54) + return tiny*__copysign(tiny,x); /*underflow*/ + k += 54; /* subnormal result */ + INSERT_WORDS64(x,(ix&INT64_C(0x800fffffffffffff))|(k<<52)); + return x*twom54; +} +weak_alias (__scalbln, scalbln) +#ifdef NO_LONG_DOUBLE +strong_alias (__scalbln, __scalblnl) +weak_alias (__scalbln, scalblnl) +#endif |