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#include "ieee754dp.h"
24
25s64 ieee754sp_tlong(union ieee754sp x)
26{
27	u32 residue;
28	int round;
29	int sticky;
30	int odd;
31
32	COMPXDP;		/* <-- need 64-bit mantissa tmp */
33
34	ieee754_clearcx();
35
36	EXPLODEXSP;
37	FLUSHXSP;
38
39	switch (xc) {
40	case IEEE754_CLASS_SNAN:
41	case IEEE754_CLASS_QNAN:
42	case IEEE754_CLASS_INF:
43		ieee754_setcx(IEEE754_INVALID_OPERATION);
44		return ieee754di_indef();
45
46	case IEEE754_CLASS_ZERO:
47		return 0;
48
49	case IEEE754_CLASS_DNORM:
50	case IEEE754_CLASS_NORM:
51		break;
52	}
53	if (xe >= 63) {
54		/* look for valid corner case */
55		if (xe == 63 && xs && xm == SP_HIDDEN_BIT)
56			return -0x8000000000000000LL;
57		/* Set invalid. We will only use overflow for floating
58		   point overflow */
59		ieee754_setcx(IEEE754_INVALID_OPERATION);
60		return ieee754di_indef();
61	}
62	/* oh gawd */
63	if (xe > SP_FBITS) {
64		xm <<= xe - SP_FBITS;
65	} else if (xe < SP_FBITS) {
66		if (xe < -1) {
67			residue = xm;
68			round = 0;
69			sticky = residue != 0;
70			xm = 0;
71		} else {
72			residue = xm << (32 - SP_FBITS + xe);
73			round = (residue >> 31) != 0;
74			sticky = (residue << 1) != 0;
75			xm >>= SP_FBITS - xe;
76		}
77		odd = (xm & 0x1) != 0x0;
78		switch (ieee754_csr.rm) {
79		case FPU_CSR_RN:
80			if (round && (sticky || odd))
81				xm++;
82			break;
83		case FPU_CSR_RZ:
84			break;
85		case FPU_CSR_RU:	/* toward +Infinity */
86			if ((round || sticky) && !xs)
87				xm++;
88			break;
89		case FPU_CSR_RD:	/* toward -Infinity */
90			if ((round || sticky) && xs)
91				xm++;
92			break;
93		}
94		if ((xm >> 63) != 0) {
95			/* This can happen after rounding */
96			ieee754_setcx(IEEE754_INVALID_OPERATION);
97			return ieee754di_indef();
98		}
99		if (round || sticky)
100			ieee754_setcx(IEEE754_INEXACT);
101	}
102	if (xs)
103		return -xm;
104	else
105		return xm;
106}
107