diff options
Diffstat (limited to 'REORG.TODO/sysdeps/ieee754/ldbl-128/s_scalbnl.c')
-rw-r--r-- | REORG.TODO/sysdeps/ieee754/ldbl-128/s_scalbnl.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/ieee754/ldbl-128/s_scalbnl.c b/REORG.TODO/sysdeps/ieee754/ldbl-128/s_scalbnl.c new file mode 100644 index 0000000000..e6fe796079 --- /dev/null +++ b/REORG.TODO/sysdeps/ieee754/ldbl-128/s_scalbnl.c @@ -0,0 +1,62 @@ +/* s_scalbnl.c -- long double version of s_scalbn.c. + * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. + */ + +/* @(#)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. + * ==================================================== + */ + +#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 + * manipulation rather than by actually performing an + * exponentiation or a multiplication. + */ + +#include <math.h> +#include <math_private.h> + +static const _Float128 +two114 = L(2.0769187434139310514121985316880384E+34), /* 0x4071000000000000, 0 */ +twom114 = L(4.8148248609680896326399448564623183E-35), /* 0x3F8D000000000000, 0 */ +huge = L(1.0E+4900), +tiny = L(1.0E-4900); + +_Float128 __scalbnl (_Float128 x, int n) +{ + int64_t k,hx,lx; + GET_LDOUBLE_WORDS64(hx,lx,x); + k = (hx>>48)&0x7fff; /* extract exponent */ + if (k==0) { /* 0 or subnormal x */ + if ((lx|(hx&0x7fffffffffffffffULL))==0) return x; /* +-0 */ + x *= two114; + GET_LDOUBLE_MSW64(hx,x); + k = ((hx>>48)&0x7fff) - 114; + } + if (k==0x7fff) return x+x; /* NaN or Inf */ + if (n< -50000) return tiny*__copysignl(tiny,x); /*underflow*/ + if (n> 50000 || k+n > 0x7ffe) + return huge*__copysignl(huge,x); /* overflow */ + /* Now k and n are bounded we know that k = k+n does not + overflow. */ + k = k+n; + if (k > 0) /* normal result */ + {SET_LDOUBLE_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); return x;} + if (k <= -114) + return tiny*__copysignl(tiny,x); /*underflow*/ + k += 114; /* subnormal result */ + SET_LDOUBLE_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); + return x*twom114; +} |