1/* IEEE754 floating point arithmetic
2 * single precision
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
7 *
8 *  This program is free software; you can distribute it and/or modify it
9 *  under the terms of the GNU General Public License (Version 2) as
10 *  published by the Free Software Foundation.
11 *
12 *  This program is distributed in the hope it will be useful, but WITHOUT
13 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15 *  for more details.
16 *
17 *  You should have received a copy of the GNU General Public License along
18 *  with this program; if not, write to the Free Software Foundation, Inc.,
19 *  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
20 */
21
22#include "ieee754sp.h"
23
24int ieee754sp_tint(union ieee754sp x)
25{
26	u32 residue;
27	int round;
28	int sticky;
29	int odd;
30
31	COMPXSP;
32
33	ieee754_clearcx();
34
35	EXPLODEXSP;
36	FLUSHXSP;
37
38	switch (xc) {
39	case IEEE754_CLASS_SNAN:
40	case IEEE754_CLASS_QNAN:
41	case IEEE754_CLASS_INF:
42		ieee754_setcx(IEEE754_INVALID_OPERATION);
43		return ieee754si_indef();
44
45	case IEEE754_CLASS_ZERO:
46		return 0;
47
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		ieee754_setcx(IEEE754_INVALID_OPERATION);
59		return ieee754si_indef();
60	}
61	/* oh gawd */
62	if (xe > SP_FBITS) {
63		xm <<= xe - SP_FBITS;
64	} else {
65		if (xe < -1) {
66			residue = xm;
67			round = 0;
68			sticky = residue != 0;
69			xm = 0;
70		} else {
71			/* Shifting a u32 32 times does not work,
72			* so we do it in two steps. Be aware that xe
73			* may be -1 */
74			residue = xm << (xe + 1);
75			residue <<= 31 - SP_FBITS;
76			round = (residue >> 31) != 0;
77			sticky = (residue << 1) != 0;
78			xm >>= SP_FBITS - xe;
79		}
80		odd = (xm & 0x1) != 0x0;
81		switch (ieee754_csr.rm) {
82		case FPU_CSR_RN:
83			if (round && (sticky || odd))
84				xm++;
85			break;
86		case FPU_CSR_RZ:
87			break;
88		case FPU_CSR_RU:	/* toward +Infinity */
89			if ((round || sticky) && !xs)
90				xm++;
91			break;
92		case FPU_CSR_RD:	/* toward -Infinity */
93			if ((round || sticky) && xs)
94				xm++;
95			break;
96		}
97		if ((xm >> 31) != 0) {
98			/* This can happen after rounding */
99			ieee754_setcx(IEEE754_INVALID_OPERATION);
100			return ieee754si_indef();
101		}
102		if (round || sticky)
103			ieee754_setcx(IEEE754_INEXACT);
104	}
105	if (xs)
106		return -xm;
107	else
108		return xm;
109}
110