| author | Rich Felker <dalias@aerifal.cx> | 2012年03月13日 01:17:53 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2012年03月13日 01:17:53 -0400 |
| commit | b69f695acedd4ce2798ef9ea28d834ceccc789bd (patch) | |
| tree | eafd98b9b75160210f3295ac074d699f863d958e /src/math/modff.c | |
| parent | d46cf2e14cc4df7cc75e77d7009fcb6df1f48a33 (diff) | |
| download | musl-b69f695acedd4ce2798ef9ea28d834ceccc789bd.tar.gz | |
| -rw-r--r-- | src/math/modff.c | 51 |
diff --git a/src/math/modff.c b/src/math/modff.c new file mode 100644 index 00000000..d535314c --- /dev/null +++ b/src/math/modff.c @@ -0,0 +1,51 @@ +/* origin: FreeBSD /usr/src/lib/msun/src/s_modff.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 "libm.h" + +static const float one = 1.0; + +float modff(float x, float *iptr) +{ + 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; + } + 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; + } + SET_FLOAT_WORD(*iptr, i0&~i); + return x - *iptr; + } else { /* no fraction part */ + uint32_t ix; + *iptr = x*one; + if (x != x) /* NaN */ + return x; + GET_FLOAT_WORD(ix, x); + SET_FLOAT_WORD(x, ix & 0x80000000); /* return +-0 */ + return x; + } +} |