| /* s_logbf.c -- float version of s_logb.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 <sys/cdefs.h> |
| __FBSDID("$FreeBSD$"); |
| |
| #include "math.h" |
| #include "math_private.h" |
| |
| static const float |
| two25 = 3.355443200e+07; /* 0x4c000000 */ |
| |
| float |
| logbf(float x) |
| { |
| int32_t ix; |
| GET_FLOAT_WORD(ix,x); |
| ix &= 0x7fffffff; /* high |x| */ |
| if(ix==0) return (float)-1.0/fabsf(x); |
| if(ix>=0x7f800000) return x*x; |
| if(ix<0x00800000) { |
| x *= two25; /* convert subnormal x to normal */ |
| GET_FLOAT_WORD(ix,x); |
| ix &= 0x7fffffff; |
| return (float) ((ix>>23)-127-25); |
| } else |
| return (float) ((ix>>23)-127); |
| } |
