1 /* s_logbf.c -- float version of s_logb.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 16 #include "math.h" 17 #include "math_private.h" 18 19 float 20 logbf(float x) 21 { 22 int32_t ix; 23 GET_FLOAT_WORD(ix,x); 24 ix &= 0x7fffffff; /* high |x| */ 25 if(ix==0) return (float)-1.0/fabsf(x); 26 if(ix>=0x7f800000) return x*x; 27 if((ix>>=23)==0) /* IEEE 754 logb */ 28 return -126.0; 29 else 30 return (float) (ix-127); 31 } 32