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circuitpython/lib/libm/sf_frexp.c

70 lines
1.6 KiB

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* These math functions are taken from newlib-nano-2, the newlib/libm/math
* directory, available from https://github.com/32bitmicro/newlib-nano-2.
*
* Appropriate copyright headers are reproduced below.
*/
/* sf_frexp.c -- float version of s_frexp.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 "fdlibm.h"
#ifdef __STDC__
static const float
#else
static float
#endif
two25 = 3.3554432000e+07; /* 0x4c000000 */
#ifdef __STDC__
float frexpf(float x, int *eptr)
#else
float frexpf(x, eptr)
float x; int *eptr;
#endif
{
__int32_t hx, ix;
GET_FLOAT_WORD(hx,x);
ix = 0x7fffffff&hx;
*eptr = 0;
if(!FLT_UWORD_IS_FINITE(ix)||FLT_UWORD_IS_ZERO(ix)) return x; /* 0,inf,nan */
if (FLT_UWORD_IS_SUBNORMAL(ix)) { /* subnormal */
x *= two25;
GET_FLOAT_WORD(hx,x);
ix = hx&0x7fffffff;
*eptr = -25;
}
*eptr += (ix>>23)-126;
hx = (hx&0x807fffff)|0x3f000000;
SET_FLOAT_WORD(x,hx);
return x;
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
double frexp(double x, int *eptr)
#else
double frexp(x, eptr)
double x; int *eptr;
#endif
{
return (double) frexpf((float) x, eptr);
}
#endif /* defined(_DOUBLE_IS_32BITS) */