1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 NetWinder Floating Point Emulator
4 (c) Rebel.COM, 1998,1999
5 (c) Philip Blundell, 2001
6
7 Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
8
9 */
10
11 #include "fpa11.h"
12 #include "fpopcode.h"
13
14 unsigned int SingleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);
15 unsigned int DoubleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);
16 unsigned int ExtendedCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);
17
18 unsigned int EmulateCPDO(const unsigned int opcode)
19 {
20 FPA11 *fpa11 = GET_FPA11();
21 FPREG *rFd;
22 unsigned int nType, nDest, nRc;
23 struct roundingData roundData;
24
25 /* Get the destination size. If not valid let Linux perform
26 an invalid instruction trap. */
27 nDest = getDestinationSize(opcode);
28 if (typeNone == nDest)
29 return 0;
30
31 roundData.mode = SetRoundingMode(opcode);
32 roundData.precision = SetRoundingPrecision(opcode);
33 roundData.exception = 0;
34
35 /* Compare the size of the operands in Fn and Fm.
36 Choose the largest size and perform operations in that size,
37 in order to make use of all the precision of the operands.
38 If Fm is a constant, we just grab a constant of a size
39 matching the size of the operand in Fn. */
40 if (MONADIC_INSTRUCTION(opcode))
41 nType = nDest;
42 else
43 nType = fpa11->fType[getFn(opcode)];
44
45 if (!CONSTANT_FM(opcode)) {
46 register unsigned int Fm = getFm(opcode);
47 if (nType < fpa11->fType[Fm]) {
48 nType = fpa11->fType[Fm];
49 }
50 }
51
52 rFd = &fpa11->fpreg[getFd(opcode)];
53
54 switch (nType) {
55 case typeSingle:
56 nRc = SingleCPDO(&roundData, opcode, rFd);
57 break;
58 case typeDouble:
59 nRc = DoubleCPDO(&roundData, opcode, rFd);
60 break;
61 #ifdef CONFIG_FPE_NWFPE_XP
62 case typeExtended:
63 nRc = ExtendedCPDO(&roundData, opcode, rFd);
64 break;
65 #endif
66 default:
67 nRc = 0;
68 }
69
70 /* The CPDO functions used to always set the destination type
71 to be the same as their working size. */
72
73 if (nRc != 0) {
74 /* If the operation succeeded, check to see if the result in the
75 destination register is the correct size. If not force it
76 to be. */
77
78 fpa11->fType[getFd(opcode)] = nDest;
79
80 #ifdef CONFIG_FPE_NWFPE_XP
81 if (nDest != nType) {
82 switch (nDest) {
83 case typeSingle:
84 {
85 if (typeDouble == nType)
86 rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble);
87 else
88 rFd->fSingle = floatx80_to_float32(&roundData, rFd->fExtended);
89 }
90 break;
91
92 case typeDouble:
93 {
94 if (typeSingle == nType)
95 rFd->fDouble = float32_to_float64(rFd->fSingle);
96 else
97 rFd->fDouble = floatx80_to_float64(&roundData, rFd->fExtended);
98 }
99 break;
100
101 case typeExtended:
102 {
103 if (typeSingle == nType)
104 rFd->fExtended = float32_to_floatx80(rFd->fSingle);
105 else
106 rFd->fExtended = float64_to_floatx80(rFd->fDouble);
107 }
108 break;
109 }
110 }
111 #else
112 if (nDest != nType) {
113 if (nDest == typeSingle)
114 rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble);
115 else
116 rFd->fDouble = float32_to_float64(rFd->fSingle);
117 }
118 #endif
119 }
120
121 if (roundData.exception)
122 float_raise(roundData.exception);
123
124 return nRc;
125 }
126
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