micropython/lib/libm/sf_modf.c

83 wiersze
1.9 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* These math functions are taken from newlib-nano-2, the newlib/libm/common
* directory, available from https://github.com/32bitmicro/newlib-nano-2.
*
* Appropriate copyright headers are reproduced below.
*/
/* sf_modf.c -- float version of s_modf.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 one = 1.0f;
#else
static float one = 1.0f;
#endif
#ifdef __STDC__
float modff(float x, float *iptr)
#else
float modff(x, iptr)
float x,*iptr;
#endif
{
__int32_t i0,j0;
__uint32_t i;
GET_FLOAT_WORD(i0,x);
j0 = ((i0>>23)&0xff)-0x7f; /* exponent of x */
if(j0<23) { /* integer part in x */
if(j0<0) { /* |x|<1 */
SET_FLOAT_WORD(*iptr,i0&0x80000000); /* *iptr = +-0 */
return x;
} else {
i = (0x007fffff)>>j0;
if((i0&i)==0) { /* x is integral */
__uint32_t ix;
*iptr = x;
GET_FLOAT_WORD(ix,x);
SET_FLOAT_WORD(x,ix&0x80000000); /* return +-0 */
return x;
} else {
SET_FLOAT_WORD(*iptr,i0&(~i));
return x - *iptr;
}
}
} else { /* no fraction part */
__uint32_t ix;
*iptr = x*one;
GET_FLOAT_WORD(ix,x);
SET_FLOAT_WORD(x,ix&0x80000000); /* return +-0 */
return x;
}
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
double modf(double x, double *iptr)
#else
double modf(x, iptr)
double x,*iptr;
#endif
{
return (double) modff((float) x, (float *) iptr);
}
#endif /* defined(_DOUBLE_IS_32BITS) */