13a8617a8SJordan K. Hubbard /* s_logbf.c -- float version of s_logb.c. 23a8617a8SJordan K. Hubbard * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 33a8617a8SJordan K. Hubbard */ 43a8617a8SJordan K. Hubbard 53a8617a8SJordan K. Hubbard /* 63a8617a8SJordan K. Hubbard * ==================================================== 73a8617a8SJordan K. Hubbard * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 83a8617a8SJordan K. Hubbard * 93a8617a8SJordan K. Hubbard * Developed at SunPro, a Sun Microsystems, Inc. business. 103a8617a8SJordan K. Hubbard * Permission to use, copy, modify, and distribute this 113a8617a8SJordan K. Hubbard * software is freely granted, provided that this notice 123a8617a8SJordan K. Hubbard * is preserved. 133a8617a8SJordan K. Hubbard * ==================================================== 143a8617a8SJordan K. Hubbard */ 153a8617a8SJordan K. Hubbard 163a8617a8SJordan K. Hubbard #ifndef lint 177f3dea24SPeter Wemm static char rcsid[] = "$FreeBSD$"; 183a8617a8SJordan K. Hubbard #endif 193a8617a8SJordan K. Hubbard 203a8617a8SJordan K. Hubbard #include "math.h" 213a8617a8SJordan K. Hubbard #include "math_private.h" 223a8617a8SJordan K. Hubbard 2359b19ff1SAlfred Perlstein float 2459b19ff1SAlfred Perlstein logbf(float x) 253a8617a8SJordan K. Hubbard { 263a8617a8SJordan K. Hubbard int32_t ix; 273a8617a8SJordan K. Hubbard GET_FLOAT_WORD(ix,x); 283a8617a8SJordan K. Hubbard ix &= 0x7fffffff; /* high |x| */ 293a8617a8SJordan K. Hubbard if(ix==0) return (float)-1.0/fabsf(x); 303a8617a8SJordan K. Hubbard if(ix>=0x7f800000) return x*x; 313a8617a8SJordan K. Hubbard if((ix>>=23)==0) /* IEEE 754 logb */ 323a8617a8SJordan K. Hubbard return -126.0; 333a8617a8SJordan K. Hubbard else 343a8617a8SJordan K. Hubbard return (float) (ix-127); 353a8617a8SJordan K. Hubbard } 36