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- /* 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);
- }
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