| /* s_logbl.c -- long double version of s_logb.c. |
| * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. |
| */ |
| |
| /* |
| * ==================================================== |
| * 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 |
| |
| /* |
| * long double logbl(x) |
| * IEEE 754 logb. Included to pass IEEE test suite. Not recommend. |
| * Use ilogb instead. |
| */ |
| |
| #include <math.h> |
| #include <math_private.h> |
| |
| long double |
| __logbl (long double x) |
| { |
| int64_t lx, hx, ex; |
| |
| GET_LDOUBLE_WORDS64 (hx, lx, x); |
| hx &= 0x7fffffffffffffffLL; /* high |x| */ |
| if ((hx | lx) == 0) |
| return -1.0 / fabs (x); |
| if (hx >= 0x7fff000000000000LL) |
| return x * x; |
| if ((ex = hx >> 48) == 0) /* IEEE 754 logb */ |
| { |
| /* POSIX specifies that denormal number is treated as |
| though it were normalized. */ |
| int ma; |
| if (hx == 0) |
| ma = __builtin_clzll (lx) + 64; |
| else |
| ma = __builtin_clzll (hx); |
| ex -= ma - 16; |
| } |
| return (long double) (ex - 16383); |
| } |
| |
| weak_alias (__logbl, logbl) |
