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 "fpa11.h"
24 #include "fpopcode.h"
25
26 unsigned int SingleCPDO(const unsigned int opcode, FPREG * rFd);
27 unsigned int DoubleCPDO(const unsigned int opcode, FPREG * rFd);
28 unsigned int ExtendedCPDO(const unsigned int opcode, FPREG * rFd);
29
EmulateCPDO(const unsigned int opcode)30 unsigned int EmulateCPDO(const unsigned int opcode)
31 {
32 FPA11 *fpa11 = GET_FPA11();
33 FPREG *rFd;
34 unsigned int nType, nDest, nRc;
35
36 /* Get the destination size. If not valid let Linux perform
37 an invalid instruction trap. */
38 nDest = getDestinationSize(opcode);
39 if (typeNone == nDest)
40 return 0;
41
42 SetRoundingMode(opcode);
43
44 /* Compare the size of the operands in Fn and Fm.
45 Choose the largest size and perform operations in that size,
46 in order to make use of all the precision of the operands.
47 If Fm is a constant, we just grab a constant of a size
48 matching the size of the operand in Fn. */
49 if (MONADIC_INSTRUCTION(opcode))
50 nType = nDest;
51 else
52 nType = fpa11->fType[getFn(opcode)];
53
54 if (!CONSTANT_FM(opcode)) {
55 register unsigned int Fm = getFm(opcode);
56 if (nType < fpa11->fType[Fm]) {
57 nType = fpa11->fType[Fm];
58 }
59 }
60
61 rFd = &fpa11->fpreg[getFd(opcode)];
62
63 switch (nType) {
64 case typeSingle:
65 nRc = SingleCPDO(opcode, rFd);
66 break;
67 case typeDouble:
68 nRc = DoubleCPDO(opcode, rFd);
69 break;
70 #ifdef CONFIG_FPE_NWFPE_XP
71 case typeExtended:
72 nRc = ExtendedCPDO(opcode, rFd);
73 break;
74 #endif
75 default:
76 nRc = 0;
77 }
78
79 /* The CPDO functions used to always set the destination type
80 to be the same as their working size. */
81
82 if (nRc != 0) {
83 /* If the operation succeeded, check to see if the result in the
84 destination register is the correct size. If not force it
85 to be. */
86
87 fpa11->fType[getFd(opcode)] = nDest;
88
89 #ifdef CONFIG_FPE_NWFPE_XP
90 if (nDest != nType) {
91 switch (nDest) {
92 case typeSingle:
93 {
94 if (typeDouble == nType)
95 rFd->fSingle = float64_to_float32(rFd->fDouble);
96 else
97 rFd->fSingle = floatx80_to_float32(rFd->fExtended);
98 }
99 break;
100
101 case typeDouble:
102 {
103 if (typeSingle == nType)
104 rFd->fDouble = float32_to_float64(rFd->fSingle);
105 else
106 rFd->fDouble = floatx80_to_float64(rFd->fExtended);
107 }
108 break;
109
110 case typeExtended:
111 {
112 if (typeSingle == nType)
113 rFd->fExtended = float32_to_floatx80(rFd->fSingle);
114 else
115 rFd->fExtended = float64_to_floatx80(rFd->fDouble);
116 }
117 break;
118 }
119 }
120 #else
121 if (nDest != nType) {
122 if (nDest == typeSingle)
123 rFd->fSingle = float64_to_float32(rFd->fDouble);
124 else
125 rFd->fDouble = float32_to_float64(rFd->fSingle);
126 }
127 #endif
128 }
129
130 return nRc;
131 }
132