| /* 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 logbq(x) | |
| * IEEE 754 logb. Included to pass IEEE test suite. Not recommend. | |
| * Use ilogb instead. | |
| */ | |
| #include "quadmath-imp.h" | |
| __float128 | |
| logbq (__float128 x) | |
| { | |
| int64_t lx, hx, ex; | |
| GET_FLT128_WORDS64 (hx, lx, x); | |
| hx &= 0x7fffffffffffffffLL; /* high |x| */ | |
| if ((hx | lx) == 0) | |
| return -1.0 / fabsq (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 (__float128) (ex - 16383); | |
| } |