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sp_fint.c
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1 /* IEEE754 floating point arithmetic
2  * single precision
3  */
4 /*
5  * MIPS floating point support
6  * Copyright (C) 1994-2000 Algorithmics Ltd.
7  *
8  * ########################################################################
9  *
10  * This program is free software; you can distribute it and/or modify it
11  * under the terms of the GNU General Public License (Version 2) as
12  * published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope it will be useful, but WITHOUT
15  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17  * for more details.
18  *
19  * You should have received a copy of the GNU General Public License along
20  * with this program; if not, write to the Free Software Foundation, Inc.,
21  * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
22  *
23  * ########################################################################
24  */
25 
26 
27 #include "ieee754sp.h"
28 
29 ieee754sp ieee754sp_fint(int x)
30 {
31  unsigned xm;
32  int xe;
33  int xs;
34 
35  CLEARCX;
36 
37  if (x == 0)
38  return ieee754sp_zero(0);
39  if (x == 1 || x == -1)
40  return ieee754sp_one(x < 0);
41  if (x == 10 || x == -10)
42  return ieee754sp_ten(x < 0);
43 
44  xs = (x < 0);
45  if (xs) {
46  if (x == (1 << 31))
47  xm = ((unsigned) 1 << 31); /* max neg can't be safely negated */
48  else
49  xm = -x;
50  } else {
51  xm = x;
52  }
53  xe = SP_MBITS + 3;
54 
55  if (xm >> (SP_MBITS + 1 + 3)) {
56  /* shunt out overflow bits
57  */
58  while (xm >> (SP_MBITS + 1 + 3)) {
59  SPXSRSX1();
60  }
61  } else {
62  /* normalize in grs extended single precision
63  */
64  while ((xm >> (SP_MBITS + 3)) == 0) {
65  xm <<= 1;
66  xe--;
67  }
68  }
69  SPNORMRET1(xs, xe, xm, "fint", x);
70 }
71 
72 
73 ieee754sp ieee754sp_funs(unsigned int u)
74 {
75  if ((int) u < 0)
77  ieee754sp_fint(u & ~(1 << 31)));
78  return ieee754sp_fint(u);
79 }