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 #include "fpmodule.h" 27 #include "fpmodule.inl" 28 29 #include <linux/config.h> 30 #include <linux/compiler.h> 31 #include <linux/string.h> 32 #include <asm/system.h> 33 34 /* forward declarations */ 35 unsigned int EmulateCPDO(const unsigned int); 36 unsigned int EmulateCPDT(const unsigned int); 37 unsigned int EmulateCPRT(const unsigned int); 38 39 /* Reset the FPA11 chip. Called to initialize and reset the emulator. */ 40 static void resetFPA11(void) 41 { 42 int i; 43 FPA11 *fpa11 = GET_FPA11(); 44 45 /* initialize the register type array */ 46 for (i = 0; i <= 7; i++) { 47 fpa11->fType[i] = typeNone; 48 } 49 50 /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */ 51 fpa11->fpsr = FP_EMULATOR | BIT_AC; 52 } 53 54 void SetRoundingMode(const unsigned int opcode) 55 { 56 switch (opcode & MASK_ROUNDING_MODE) { 57 default: 58 case ROUND_TO_NEAREST: 59 float_rounding_mode = float_round_nearest_even; 60 break; 61 62 case ROUND_TO_PLUS_INFINITY: 63 float_rounding_mode = float_round_up; 64 break; 65 66 case ROUND_TO_MINUS_INFINITY: 67 float_rounding_mode = float_round_down; 68 break; 69 70 case ROUND_TO_ZERO: 71 float_rounding_mode = float_round_to_zero; 72 break; 73 } 74 } 75 76 void SetRoundingPrecision(const unsigned int opcode) 77 { 78 #ifdef CONFIG_FPE_NWFPE_XP 79 switch (opcode & MASK_ROUNDING_PRECISION) { 80 case ROUND_SINGLE: 81 floatx80_rounding_precision = 32; 82 break; 83 84 case ROUND_DOUBLE: 85 floatx80_rounding_precision = 64; 86 break; 87 88 case ROUND_EXTENDED: 89 floatx80_rounding_precision = 80; 90 break; 91 92 default: 93 floatx80_rounding_precision = 80; 94 } 95 #endif 96 } 97 98 void nwfpe_init_fpa(union fp_state *fp) 99 { 100 FPA11 *fpa11 = (FPA11 *)fp; 101 #ifdef NWFPE_DEBUG 102 printk("NWFPE: setting up state.\n"); 103 #endif 104 memset(fpa11, 0, sizeof(FPA11)); 105 resetFPA11(); 106 SetRoundingMode(ROUND_TO_NEAREST); 107 SetRoundingPrecision(ROUND_EXTENDED); 108 fpa11->initflag = 1; 109 } 110 111 /* Emulate the instruction in the opcode. */ 112 unsigned int EmulateAll(unsigned int opcode) 113 { 114 unsigned int code; 115 116 #ifdef NWFPE_DEBUG 117 printk("NWFPE: emulating opcode %08x\n", opcode); 118 #endif 119 code = opcode & 0x00000f00; 120 if (code == 0x00000100 || code == 0x00000200) { 121 /* For coprocessor 1 or 2 (FPA11) */ 122 code = opcode & 0x0e000000; 123 if (code == 0x0e000000) { 124 if (opcode & 0x00000010) { 125 /* Emulate conversion opcodes. */ 126 /* Emulate register transfer opcodes. */ 127 /* Emulate comparison opcodes. */ 128 return EmulateCPRT(opcode); 129 } else { 130 /* Emulate monadic arithmetic opcodes. */ 131 /* Emulate dyadic arithmetic opcodes. */ 132 return EmulateCPDO(opcode); 133 } 134 } else if (code == 0x0c000000) { 135 /* Emulate load/store opcodes. */ 136 /* Emulate load/store multiple opcodes. */ 137 return EmulateCPDT(opcode); 138 } 139 } 140 141 /* Invalid instruction detected. Return FALSE. */ 142 return 0; 143 } 144