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Diffstat (limited to 'lib/msun/src/s_frexp.c')
-rw-r--r-- | lib/msun/src/s_frexp.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/lib/msun/src/s_frexp.c b/lib/msun/src/s_frexp.c new file mode 100644 index 0000000..318a991 --- /dev/null +++ b/lib/msun/src/s_frexp.c @@ -0,0 +1,56 @@ +/* @(#)s_frexp.c 5.1 93/09/24 */ +/* + * ==================================================== + * 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 <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * for non-zero x + * x = frexp(arg,&exp); + * return a double fp quantity x such that 0.5 <= |x| <1.0 + * and the corresponding binary exponent "exp". That is + * arg = x*2^exp. + * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg + * with *exp=0. + */ + +#include <float.h> + +#include "math.h" +#include "math_private.h" + +static const double +two54 = 1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */ + +double +frexp(double x, int *eptr) +{ + int32_t hx, ix, lx; + EXTRACT_WORDS(hx,lx,x); + ix = 0x7fffffff&hx; + *eptr = 0; + if(ix>=0x7ff00000||((ix|lx)==0)) return x; /* 0,inf,nan */ + if (ix<0x00100000) { /* subnormal */ + x *= two54; + GET_HIGH_WORD(hx,x); + ix = hx&0x7fffffff; + *eptr = -54; + } + *eptr += (ix>>20)-1022; + hx = (hx&0x800fffff)|0x3fe00000; + SET_HIGH_WORD(x,hx); + return x; +} + +#if (LDBL_MANT_DIG == 53) +__weak_reference(frexp, frexpl); +#endif |