1/* IEEE754 floating point arithmetic
2 * single precision
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
7 * http://www.algor.co.uk
8 *
9 * ########################################################################
10 *
11 *  This program is free software; you can distribute it and/or modify it
12 *  under the terms of the GNU General Public License (Version 2) as
13 *  published by the Free Software Foundation.
14 *
15 *  This program is distributed in the hope it will be useful, but WITHOUT
16 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
18 *  for more details.
19 *
20 *  You should have received a copy of the GNU General Public License along
21 *  with this program; if not, write to the Free Software Foundation, Inc.,
22 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
23 *
24 * ########################################################################
25 */
26
27
28#include <linux/kernel.h>
29#include "ieee754sp.h"
30
31int ieee754sp_tint(ieee754sp x)
32{
33	COMPXSP;
34
35	CLEARCX;
36
37	EXPLODEXSP;
38	FLUSHXSP;
39
40	switch (xc) {
41	case IEEE754_CLASS_SNAN:
42	case IEEE754_CLASS_QNAN:
43	case IEEE754_CLASS_INF:
44		SETCX(IEEE754_INVALID_OPERATION);
45		return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
46	case IEEE754_CLASS_ZERO:
47		return 0;
48	case IEEE754_CLASS_DNORM:
49	case IEEE754_CLASS_NORM:
50		break;
51	}
52	if (xe >= 31) {
53		/* look for valid corner case */
54		if (xe == 31 && xs && xm == SP_HIDDEN_BIT)
55			return -0x80000000;
56		/* Set invalid. We will only use overflow for floating
57		   point overflow */
58		SETCX(IEEE754_INVALID_OPERATION);
59		return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
60	}
61	/* oh gawd */
62	if (xe > SP_MBITS) {
63		xm <<= xe - SP_MBITS;
64	} else {
65		u32 residue;
66		int round;
67		int sticky;
68		int odd;
69
70		if (xe < -1) {
71			residue = xm;
72			round = 0;
73			sticky = residue != 0;
74			xm = 0;
75		}
76		else {
77			/* Shifting a u32 32 times does not work,
78			* so we do it in two steps. Be aware that xe
79			* may be -1 */
80			residue = xm << (xe + 1);
81			residue <<= 31 - SP_MBITS;
82			round = (residue >> 31) != 0;
83			sticky = (residue << 1) != 0;
84			xm >>= SP_MBITS - xe;
85		}
86		odd = (xm & 0x1) != 0x0;
87		switch (ieee754_csr.rm) {
88		case IEEE754_RN:
89			if (round && (sticky || odd))
90				xm++;
91			break;
92		case IEEE754_RZ:
93			break;
94		case IEEE754_RU:	/* toward +Infinity */
95			if ((round || sticky) && !xs)
96				xm++;
97			break;
98		case IEEE754_RD:	/* toward -Infinity */
99			if ((round || sticky) && xs)
100				xm++;
101			break;
102		}
103		if ((xm >> 31) != 0) {
104			/* This can happen after rounding */
105			SETCX(IEEE754_INVALID_OPERATION);
106			return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
107		}
108		if (round || sticky)
109			SETCX(IEEE754_INEXACT);
110	}
111	if (xs)
112		return -xm;
113	else
114		return xm;
115}
116
117
118unsigned int ieee754sp_tuns(ieee754sp x)
119{
120	ieee754sp hb = ieee754sp_1e31();
121
122	/* what if x < 0 ?? */
123	if (ieee754sp_lt(x, hb))
124		return (unsigned) ieee754sp_tint(x);
125
126	return (unsigned) ieee754sp_tint(ieee754sp_sub(x, hb)) |
127	    ((unsigned) 1 << 31);
128}
129