| /* sf_ilogb.c -- float version of s_ilogb.c. |
| * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
| */ |
| |
| /* |
| * ==================================================== |
| * 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. |
| * ==================================================== |
| */ |
| |
| #include "fdlibm.h" |
| #include <limits.h> |
| |
| #ifdef __STDC__ |
| int ilogbf(float x) |
| #else |
| int ilogbf(x) |
| float x; |
| #endif |
| { |
| __int32_t hx,ix; |
| |
| GET_FLOAT_WORD(hx,x); |
| hx &= 0x7fffffff; |
| if(FLT_UWORD_IS_ZERO(hx)) |
| return - INT_MAX; /* ilogb(0) = 0x80000001 */ |
| if(FLT_UWORD_IS_SUBNORMAL(hx)) { |
| for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1; |
| return ix; |
| } |
| else if (!FLT_UWORD_IS_FINITE(hx)) return INT_MAX; |
| else return (hx>>23)-127; |
| } |
| |
| #ifdef _DOUBLE_IS_32BITS |
| |
| #ifdef __STDC__ |
| int ilogb(double x) |
| #else |
| int ilogb(x) |
| double x; |
| #endif |
| { |
| return ilogbf((float) x); |
| } |
| |
| #endif /* defined(_DOUBLE_IS_32BITS) */ |