xref: /netbsd-src/external/gpl3/gcc.old/dist/libquadmath/math/rintq.c (revision 627f7eb200a4419d89b531d55fccd2ee3ffdcde0)
1*627f7eb2Smrg /* s_rintl.c -- long double version of s_rint.c.
2*627f7eb2Smrg  * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
3*627f7eb2Smrg  */
4*627f7eb2Smrg 
5*627f7eb2Smrg /*
6*627f7eb2Smrg  * ====================================================
7*627f7eb2Smrg  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8*627f7eb2Smrg  *
9*627f7eb2Smrg  * Developed at SunPro, a Sun Microsystems, Inc. business.
10*627f7eb2Smrg  * Permission to use, copy, modify, and distribute this
11*627f7eb2Smrg  * software is freely granted, provided that this notice
12*627f7eb2Smrg  * is preserved.
13*627f7eb2Smrg  * ====================================================
14*627f7eb2Smrg  */
15*627f7eb2Smrg 
16*627f7eb2Smrg #if defined(LIBM_SCCS) && !defined(lint)
17*627f7eb2Smrg static char rcsid[] = "NetBSD: ";
18*627f7eb2Smrg #endif
19*627f7eb2Smrg 
20*627f7eb2Smrg /*
21*627f7eb2Smrg  * rintq(x)
22*627f7eb2Smrg  * Return x rounded to integral value according to the prevailing
23*627f7eb2Smrg  * rounding mode.
24*627f7eb2Smrg  * Method:
25*627f7eb2Smrg  *	Using floating addition.
26*627f7eb2Smrg  * Exception:
27*627f7eb2Smrg  *	Inexact flag raised if x not equal to rintq(x).
28*627f7eb2Smrg  */
29*627f7eb2Smrg 
30*627f7eb2Smrg #define NO_MATH_REDIRECT
31*627f7eb2Smrg 
32*627f7eb2Smrg #include "quadmath-imp.h"
33*627f7eb2Smrg 
34*627f7eb2Smrg static const __float128
35*627f7eb2Smrg TWO112[2]={
36*627f7eb2Smrg   5.19229685853482762853049632922009600E+33L, /* 0x406F000000000000, 0 */
37*627f7eb2Smrg  -5.19229685853482762853049632922009600E+33L  /* 0xC06F000000000000, 0 */
38*627f7eb2Smrg };
39*627f7eb2Smrg 
rintq(__float128 x)40*627f7eb2Smrg __float128 rintq(__float128 x)
41*627f7eb2Smrg {
42*627f7eb2Smrg 	int64_t i0,j0,sx;
43*627f7eb2Smrg 	uint64_t i1 __attribute__ ((unused));
44*627f7eb2Smrg 	__float128 w,t;
45*627f7eb2Smrg 	GET_FLT128_WORDS64(i0,i1,x);
46*627f7eb2Smrg 	sx = (((uint64_t)i0)>>63);
47*627f7eb2Smrg 	j0 = ((i0>>48)&0x7fff)-0x3fff;
48*627f7eb2Smrg 	if(j0<112) {
49*627f7eb2Smrg 	    if(j0<0) {
50*627f7eb2Smrg 	        w = TWO112[sx]+x;
51*627f7eb2Smrg 	        t = w-TWO112[sx];
52*627f7eb2Smrg 		GET_FLT128_MSW64(i0,t);
53*627f7eb2Smrg 		SET_FLT128_MSW64(t,(i0&0x7fffffffffffffffLL)|(sx<<63));
54*627f7eb2Smrg 	        return t;
55*627f7eb2Smrg 	    }
56*627f7eb2Smrg 	} else {
57*627f7eb2Smrg 	    if(j0==0x4000) return x+x;	/* inf or NaN */
58*627f7eb2Smrg 	    else return x;		/* x is integral */
59*627f7eb2Smrg 	}
60*627f7eb2Smrg 	w = TWO112[sx]+x;
61*627f7eb2Smrg 	return w-TWO112[sx];
62*627f7eb2Smrg }
63