| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 1 | /* s_ilogbf.c -- float version of s_ilogb.c. |
| 2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
| 3 | */ |
| 4 | |
| 5 | /* |
| 6 | * ==================================================== |
| 7 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| 8 | * |
| 9 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
| 10 | * Permission to use, copy, modify, and distribute this |
| 11 | * software is freely granted, provided that this notice |
| 12 | * is preserved. |
| 13 | * ==================================================== |
| 14 | */ |
| 15 | |
| Elliott Hughes | a0ee078 | 2013-01-30 19:06:37 -0800 | [diff] [blame] | 16 | #include <sys/cdefs.h> |
| 17 | __FBSDID("$FreeBSD$"); |
| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 18 | |
| 19 | #include <limits.h> |
| 20 | |
| 21 | #include "math.h" |
| 22 | #include "math_private.h" |
| 23 | |
| 24 | int ilogbf(float x) |
| 25 | { |
| 26 | int32_t hx,ix; |
| 27 | |
| 28 | GET_FLOAT_WORD(hx,x); |
| 29 | hx &= 0x7fffffff; |
| 30 | if(hx<0x00800000) { |
| 31 | if(hx==0) |
| 32 | return FP_ILOGB0; |
| 33 | else /* subnormal x */ |
| 34 | for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1; |
| 35 | return ix; |
| 36 | } |
| 37 | else if (hx<0x7f800000) return (hx>>23)-127; |
| 38 | else if (hx>0x7f800000) return FP_ILOGBNAN; |
| 39 | else return INT_MAX; |
| 40 | } |