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(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd); 28 unsigned int DoubleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd); 29 unsigned int ExtendedCPDO(struct roundingData *roundData, 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 struct roundingData roundData; 37 38 /* Get the destination size. If not valid let Linux perform 39 an invalid instruction trap. */ 40 nDest = getDestinationSize(opcode); 41 if (typeNone == nDest) 42 return 0; 43 44 roundData.mode = SetRoundingMode(opcode); 45 roundData.precision = SetRoundingPrecision(opcode); 46 roundData.exception = 0; 47 48 /* Compare the size of the operands in Fn and Fm. 49 Choose the largest size and perform operations in that size, 50 in order to make use of all the precision of the operands. 51 If Fm is a constant, we just grab a constant of a size 52 matching the size of the operand in Fn. */ 53 if (MONADIC_INSTRUCTION(opcode)) 54 nType = nDest; 55 else 56 nType = fpa11->fType[getFn(opcode)]; 57 58 if (!CONSTANT_FM(opcode)) { 59 register unsigned int Fm = getFm(opcode); 60 if (nType < fpa11->fType[Fm]) { 61 nType = fpa11->fType[Fm]; 62 } 63 } 64 65 rFd = &fpa11->fpreg[getFd(opcode)]; 66 67 switch (nType) { 68 case typeSingle: 69 nRc = SingleCPDO(&roundData, opcode, rFd); 70 break; 71 case typeDouble: 72 nRc = DoubleCPDO(&roundData, opcode, rFd); 73 break; 74 #ifdef CONFIG_FPE_NWFPE_XP 75 case typeExtended: 76 nRc = ExtendedCPDO(&roundData, opcode, rFd); 77 break; 78 #endif 79 default: 80 nRc = 0; 81 } 82 83 /* The CPDO functions used to always set the destination type 84 to be the same as their working size. */ 85 86 if (nRc != 0) { 87 /* If the operation succeeded, check to see if the result in the 88 destination register is the correct size. If not force it 89 to be. */ 90 91 fpa11->fType[getFd(opcode)] = nDest; 92 93 #ifdef CONFIG_FPE_NWFPE_XP 94 if (nDest != nType) { 95 switch (nDest) { 96 case typeSingle: 97 { 98 if (typeDouble == nType) 99 rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble); 100 else 101 rFd->fSingle = floatx80_to_float32(&roundData, rFd->fExtended); 102 } 103 break; 104 105 case typeDouble: 106 { 107 if (typeSingle == nType) 108 rFd->fDouble = float32_to_float64(rFd->fSingle); 109 else 110 rFd->fDouble = floatx80_to_float64(&roundData, rFd->fExtended); 111 } 112 break; 113 114 case typeExtended: 115 { 116 if (typeSingle == nType) 117 rFd->fExtended = float32_to_floatx80(rFd->fSingle); 118 else 119 rFd->fExtended = float64_to_floatx80(rFd->fDouble); 120 } 121 break; 122 } 123 } 124 #else 125 if (nDest != nType) { 126 if (nDest == typeSingle) 127 rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble); 128 else 129 rFd->fDouble = float32_to_float64(rFd->fSingle); 130 } 131 #endif 132 } 133 134 if (roundData.exception) 135 float_raise(roundData.exception); 136 137 return nRc; 138 } 139