| /* s_ilogbl.c -- long double version of s_ilogb.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 |
| |
| /* ilogbl(long double x) |
| * return the binary exponent of non-zero x |
| * ilogbl(0) = FP_ILOGB0 |
| * ilogbl(NaN) = FP_ILOGBNAN (no signal is raised) |
| * ilogbl(+-Inf) = INT_MAX (no signal is raised) |
| */ |
| |
| #include <limits.h> |
| #include <math.h> |
| #include <math_private.h> |
| #include <math_ldbl_opt.h> |
| |
| int __ieee754_ilogbl(long double x) |
| { |
| int64_t hx; |
| int ix; |
| double xhi; |
| |
| xhi = ldbl_high (x); |
| EXTRACT_WORDS64 (hx, xhi); |
| hx &= 0x7fffffffffffffffLL; |
| if(hx <= 0x0010000000000000LL) { |
| if(hx==0) |
| return FP_ILOGB0; /* ilogbl(0) = FP_ILOGB0 */ |
| else /* subnormal x */ |
| for (ix = -1022, hx<<=11; hx>0; hx<<=1) ix -=1; |
| return ix; |
| } |
| else if (hx<0x7ff0000000000000LL) return (hx>>52)-0x3ff; |
| else if (FP_ILOGBNAN != INT_MAX) { |
| /* ISO C99 requires ilogbl(+-Inf) == INT_MAX. */ |
| if (hx==0x7ff0000000000000LL) |
| return INT_MAX; |
| } |
| return FP_ILOGBNAN; |
| } |
