Linux-2.6.12-rc2
[linux-2.6.git] / arch / arm / nwfpe / fpa11_cpdo.c
1 /*
2     NetWinder Floating Point Emulator
3     (c) Rebel.COM, 1998,1999
4     (c) Philip Blundell, 2001
5
6     Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
7
8     This program is free software; you can redistribute it and/or modify
9     it under the terms of the GNU General Public License as published by
10     the Free Software Foundation; either version 2 of the License, or
11     (at your option) any later version.
12
13     This program is distributed in the hope that it will be useful,
14     but WITHOUT ANY WARRANTY; without even the implied warranty of
15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16     GNU General Public License for more details.
17
18     You should have received a copy of the GNU General Public License
19     along with this program; if not, write to the Free Software
20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23 #include <linux/config.h>
24 #include "fpa11.h"
25 #include "fpopcode.h"
26
27 unsigned int SingleCPDO(const unsigned int opcode, FPREG * rFd);
28 unsigned int DoubleCPDO(const unsigned int opcode, FPREG * rFd);
29 unsigned int ExtendedCPDO(const unsigned int opcode, FPREG * rFd);
30
31 unsigned int EmulateCPDO(const unsigned int opcode)
32 {
33         FPA11 *fpa11 = GET_FPA11();
34         FPREG *rFd;
35         unsigned int nType, nDest, nRc;
36
37         /* Get the destination size.  If not valid let Linux perform
38            an invalid instruction trap. */
39         nDest = getDestinationSize(opcode);
40         if (typeNone == nDest)
41                 return 0;
42
43         SetRoundingMode(opcode);
44
45         /* Compare the size of the operands in Fn and Fm.
46            Choose the largest size and perform operations in that size,
47            in order to make use of all the precision of the operands.
48            If Fm is a constant, we just grab a constant of a size
49            matching the size of the operand in Fn. */
50         if (MONADIC_INSTRUCTION(opcode))
51                 nType = nDest;
52         else
53                 nType = fpa11->fType[getFn(opcode)];
54
55         if (!CONSTANT_FM(opcode)) {
56                 register unsigned int Fm = getFm(opcode);
57                 if (nType < fpa11->fType[Fm]) {
58                         nType = fpa11->fType[Fm];
59                 }
60         }
61
62         rFd = &fpa11->fpreg[getFd(opcode)];
63
64         switch (nType) {
65         case typeSingle:
66                 nRc = SingleCPDO(opcode, rFd);
67                 break;
68         case typeDouble:
69                 nRc = DoubleCPDO(opcode, rFd);
70                 break;
71 #ifdef CONFIG_FPE_NWFPE_XP
72         case typeExtended:
73                 nRc = ExtendedCPDO(opcode, rFd);
74                 break;
75 #endif
76         default:
77                 nRc = 0;
78         }
79
80         /* The CPDO functions used to always set the destination type
81            to be the same as their working size. */
82
83         if (nRc != 0) {
84                 /* If the operation succeeded, check to see if the result in the
85                    destination register is the correct size.  If not force it
86                    to be. */
87
88                 fpa11->fType[getFd(opcode)] = nDest;
89
90 #ifdef CONFIG_FPE_NWFPE_XP
91                 if (nDest != nType) {
92                         switch (nDest) {
93                         case typeSingle:
94                                 {
95                                         if (typeDouble == nType)
96                                                 rFd->fSingle = float64_to_float32(rFd->fDouble);
97                                         else
98                                                 rFd->fSingle = floatx80_to_float32(rFd->fExtended);
99                                 }
100                                 break;
101
102                         case typeDouble:
103                                 {
104                                         if (typeSingle == nType)
105                                                 rFd->fDouble = float32_to_float64(rFd->fSingle);
106                                         else
107                                                 rFd->fDouble = floatx80_to_float64(rFd->fExtended);
108                                 }
109                                 break;
110
111                         case typeExtended:
112                                 {
113                                         if (typeSingle == nType)
114                                                 rFd->fExtended = float32_to_floatx80(rFd->fSingle);
115                                         else
116                                                 rFd->fExtended = float64_to_floatx80(rFd->fDouble);
117                                 }
118                                 break;
119                         }
120                 }
121 #else
122                 if (nDest != nType) {
123                         if (nDest == typeSingle)
124                                 rFd->fSingle = float64_to_float32(rFd->fDouble);
125                         else
126                                 rFd->fDouble = float32_to_float64(rFd->fSingle);
127                 }
128 #endif
129         }
130
131         return nRc;
132 }