gcc/libquadmath/math/frexpq.c

50 lines
1.4 KiB
C

/* frexpq.c -- __float128 version of s_frexp.c.
* Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
*/
/*
* ====================================================
* 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.
* ====================================================
*/
/*
* for non-zero x
* x = frexpq(arg,&exp);
* return a __float128 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 frexpq(arg,&exp) returns arg
* with *exp=0.
*/
#include "quadmath-imp.h"
static const __float128
two114 = 2.0769187434139310514121985316880384E+34Q; /* 0x4071000000000000, 0 */
__float128
frexpq (__float128 x, int *eptr)
{
uint64_t hx, lx, ix;
GET_FLT128_WORDS64(hx,lx,x);
ix = 0x7fffffffffffffffULL&hx;
*eptr = 0;
if(ix>=0x7fff000000000000ULL||((ix|lx)==0)) return x; /* 0,inf,nan */
if (ix<0x0001000000000000ULL) { /* subnormal */
x *= two114;
GET_FLT128_MSW64(hx,x);
ix = hx&0x7fffffffffffffffULL;
*eptr = -114;
}
*eptr += (ix>>48)-16382;
hx = (hx&0x8000ffffffffffffULL) | 0x3ffe000000000000ULL;
SET_FLT128_MSW64(x,hx);
return x;
}