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(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);
27 unsigned int DoubleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);
28 unsigned int ExtendedCPDO(struct roundingData *roundData, 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 struct roundingData roundData;
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 roundData.mode = SetRoundingMode(opcode);
44 roundData.precision = SetRoundingPrecision(opcode);
45 roundData.exception = 0;
46
47 /* Compare the size of the operands in Fn and Fm.
48 Choose the largest size and perform operations in that size,
49 in order to make use of all the precision of the operands.
50 If Fm is a constant, we just grab a constant of a size
51 matching the size of the operand in Fn. */
52 if (MONADIC_INSTRUCTION(opcode))
53 nType = nDest;
54 else
55 nType = fpa11->fType[getFn(opcode)];
56
57 if (!CONSTANT_FM(opcode)) {
58 register unsigned int Fm = getFm(opcode);
59 if (nType < fpa11->fType[Fm]) {
60 nType = fpa11->fType[Fm];
61 }
62 }
63
64 rFd = &fpa11->fpreg[getFd(opcode)];
65
66 switch (nType) {
67 case typeSingle:
68 nRc = SingleCPDO(&roundData, opcode, rFd);
69 break;
70 case typeDouble:
71 nRc = DoubleCPDO(&roundData, opcode, rFd);
72 break;
73 #ifdef CONFIG_FPE_NWFPE_XP
74 case typeExtended:
75 nRc = ExtendedCPDO(&roundData, opcode, rFd);
76 break;
77 #endif
78 default:
79 nRc = 0;
80 }
81
82 /* The CPDO functions used to always set the destination type
83 to be the same as their working size. */
84
85 if (nRc != 0) {
86 /* If the operation succeeded, check to see if the result in the
87 destination register is the correct size. If not force it
88 to be. */
89
90 fpa11->fType[getFd(opcode)] = nDest;
91
92 #ifdef CONFIG_FPE_NWFPE_XP
93 if (nDest != nType) {
94 switch (nDest) {
95 case typeSingle:
96 {
97 if (typeDouble == nType)
98 rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble);
99 else
100 rFd->fSingle = floatx80_to_float32(&roundData, rFd->fExtended);
101 }
102 break;
103
104 case typeDouble:
105 {
106 if (typeSingle == nType)
107 rFd->fDouble = float32_to_float64(rFd->fSingle);
108 else
109 rFd->fDouble = floatx80_to_float64(&roundData, rFd->fExtended);
110 }
111 break;
112
113 case typeExtended:
114 {
115 if (typeSingle == nType)
116 rFd->fExtended = float32_to_floatx80(rFd->fSingle);
117 else
118 rFd->fExtended = float64_to_floatx80(rFd->fDouble);
119 }
120 break;
121 }
122 }
123 #else
124 if (nDest != nType) {
125 if (nDest == typeSingle)
126 rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble);
127 else
128 rFd->fDouble = float32_to_float64(rFd->fSingle);
129 }
130 #endif
131 }
132
133 if (roundData.exception)
134 float_raise(roundData.exception);
135
136 return nRc;
137 }
138