| /* s_ilogbf.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. |
| * ==================================================== |
| */ |
| |
| #if defined(LIBM_SCCS) && !defined(lint) |
| static char rcsid[] = "$NetBSD: s_ilogbf.c,v 1.4 1995/05/10 20:47:31 jtc Exp $"; |
| #endif |
| |
| #include <limits.h> |
| #include "math.h" |
| #include "math_private.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(hx<0x00800000) { |
| if(hx==0) |
| return FP_ILOGB0; /* ilogb(0) = FP_ILOGB0 */ |
| else /* subnormal x */ |
| for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1; |
| return ix; |
| } |
| else if (hx<0x7f800000) return (hx>>23)-127; |
| else if (FP_ILOGBNAN != INT_MAX) { |
| /* ISO C99 requires ilogbf(+-Inf) == INT_MAX. */ |
| if (hx==0x7f800000) |
| return INT_MAX; |
| } |
| return FP_ILOGBNAN; |
| } |
| weak_alias (__ilogbf, ilogbf) |
