projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| f7eac6eb | 1 | /* s_ilogbf.c -- float version of s_ilogb.c. |
| f7eac6eb RM |
2 | */ |
| 3 | ||
| 4 | /* | |
| 5 | * ==================================================== | |
| 6 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. | |
| 7 | * | |
| 8 | * Developed at SunPro, a Sun Microsystems, Inc. business. | |
| 9 | * Permission to use, copy, modify, and distribute this | |
| 6973fc01 | 10 | * software is freely granted, provided that this notice |
| f7eac6eb RM |
11 | * is preserved. |
| 12 | * ==================================================== | |
| 13 | */ | |
| 14 | ||
| 15 | #if defined(LIBM_SCCS) && !defined(lint) | |
| 16 | static char rcsid[] = "$NetBSD: s_ilogbf.c,v 1.4 1995/05/10 20:47:31 jtc Exp $"; | |
| 17 | #endif | |
| 18 | ||
| 601d2942 | 19 | #include <limits.h> |
| 1ed0291c RH |
20 | #include <math.h> |
| 21 | #include <math_private.h> | |
| f7eac6eb | 22 | |
| 76da7265 | 23 | int __ieee754_ilogbf(float x) |
| f7eac6eb RM |
24 | { |
| 25 | int32_t hx,ix; | |
| 26 | ||
| 27 | GET_FLOAT_WORD(hx,x); | |
| 28 | hx &= 0x7fffffff; | |
| 29 | if(hx<0x00800000) { | |
| 6973fc01 UD |
30 | if(hx==0) |
| 31 | return FP_ILOGB0; /* ilogb(0) = FP_ILOGB0 */ | |
| f7eac6eb RM |
32 | else /* subnormal x */ |
| 33 | for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1; | |
| 34 | return ix; | |
| 35 | } | |
| 36 | else if (hx<0x7f800000) return (hx>>23)-127; | |
| 601d2942 UD |
37 | else if (FP_ILOGBNAN != INT_MAX) { |
| 38 | /* ISO C99 requires ilogbf(+-Inf) == INT_MAX. */ | |
| 39 | if (hx==0x7f800000) | |
| 40 | return INT_MAX; | |
| 41 | } | |
| 42 | return FP_ILOGBNAN; | |
| f7eac6eb | 43 | } |