xref: /openbmc/linux/arch/arm/nwfpe/fpa11_cpdo.c (revision 20e2fc42)
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