Update.
[glibc.git] / sysdeps / libm-ieee754 / s_rintf.c
blob4e5b409b2997c23b7036c5fdaf35328e0be356d8
1 /* s_rintf.c -- float version of s_rint.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
5 /*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
16 #if defined(LIBM_SCCS) && !defined(lint)
17 static char rcsid[] = "$NetBSD: s_rintf.c,v 1.4 1995/05/10 20:48:06 jtc Exp $";
18 #endif
20 #include "math.h"
21 #include "math_private.h"
23 #ifdef __STDC__
24 static const float
25 #else
26 static float
27 #endif
28 TWO23[2]={
29 8.3886080000e+06, /* 0x4b000000 */
30 -8.3886080000e+06, /* 0xcb000000 */
33 #ifdef __STDC__
34 float __rintf(float x)
35 #else
36 float __rintf(x)
37 float x;
38 #endif
40 int32_t i0,j0,sx;
41 u_int32_t i,i1;
42 float w,t;
43 GET_FLOAT_WORD(i0,x);
44 sx = (i0>>31)&1;
45 j0 = ((i0>>23)&0xff)-0x7f;
46 if(j0<23) {
47 if(j0<0) {
48 if((i0&0x7fffffff)==0) return x;
49 i1 = (i0&0x07fffff);
50 i0 &= 0xfff00000;
51 i0 |= ((i1|-i1)>>9)&0x400000;
52 SET_FLOAT_WORD(x,i0);
53 w = TWO23[sx]+x;
54 t = w-TWO23[sx];
55 GET_FLOAT_WORD(i0,t);
56 SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31));
57 return t;
58 } else {
59 i = (0x007fffff)>>j0;
60 if((i0&i)==0) return x; /* x is integral */
61 i>>=1;
62 if((i0&i)!=0) i0 = (i0&(~i))|((0x100000)>>j0);
64 } else {
65 if(j0==0x80) return x+x; /* inf or NaN */
66 else return x; /* x is integral */
68 SET_FLOAT_WORD(x,i0);
69 w = TWO23[sx]+x;
70 return w-TWO23[sx];
72 weak_alias (__rintf, rintf)