blob: 66ab2689b7e5ba6739b48b4bc2c913b76bcf1721 [file] [log] [blame]
/*
* ====================================================
* 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.
* ====================================================
*/
/* From newlib's newlib/libm/common/sf_logb.c */
#include "fdlibm_nacl.h"
float __compilerrt_logbf(float x)
{
__int32_t hx,ix;
GET_FLOAT_WORD(hx,x);
hx &= 0x7fffffff;
if(FLT_UWORD_IS_ZERO(hx)) {
float xx;
/* arg==0: return -inf and raise divide-by-zero exception */
SET_FLOAT_WORD(xx,hx); /* +0.0 */
return -1./xx; /* logbf(0) = -inf */
}
if(FLT_UWORD_IS_SUBNORMAL(hx)) {
for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
return (float) ix;
}
else if (FLT_UWORD_IS_INFINITE(hx)) return HUGE_VALF; /* x==+|-inf */
else if (FLT_UWORD_IS_NAN(hx)) return x;
else return (float) ((hx>>23)-127);
}