arch/arm/nwfpe/fpa11.c

   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 }