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/compiler.h>
  30 #include <linux/string.h>
  31
  32 /* Reset the FPA11 chip.  Called to initialize and reset the emulator. */
  33 static void resetFPA11(void)
  34 {
  35         int i;
  36         FPA11 *fpa11 = GET_FPA11();
  37
  38         /* initialize the register type array */
  39         for (i = 0; i <= 7; i++) {
  40                 fpa11->fType[i] = typeNone;
  41         }
  42
  43         /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
  44         fpa11->fpsr = FP_EMULATOR | BIT_AC;
  45 }
  46
  47 int8 SetRoundingMode(const unsigned int opcode)
  48 {
  49         switch (opcode & MASK_ROUNDING_MODE) {
  50         default:
  51         case ROUND_TO_NEAREST:
  52                 return float_round_nearest_even;
  53
  54         case ROUND_TO_PLUS_INFINITY:
  55                 return float_round_up;
  56
  57         case ROUND_TO_MINUS_INFINITY:
  58                 return float_round_down;
  59
  60         case ROUND_TO_ZERO:
  61                 return float_round_to_zero;
  62         }
  63 }
  64
  65 int8 SetRoundingPrecision(const unsigned int opcode)
  66 {
  67 #ifdef CONFIG_FPE_NWFPE_XP
  68         switch (opcode & MASK_ROUNDING_PRECISION) {
  69         case ROUND_SINGLE:
  70                 return 32;
  71
  72         case ROUND_DOUBLE:
  73                 return 64;
  74
  75         case ROUND_EXTENDED:
  76                 return 80;
  77
  78         default:
  79                 return 80;
  80         }
  81 #endif
  82         return 80;
  83 }
  84
  85 void nwfpe_init_fpa(union fp_state *fp)
  86 {
  87         FPA11 *fpa11 = (FPA11 *)fp;
  88 #ifdef NWFPE_DEBUG
  89         printk("NWFPE: setting up state.\n");
  90 #endif
  91         memset(fpa11, 0, sizeof(FPA11));
  92         resetFPA11();
  93         fpa11->initflag = 1;
  94 }
  95
  96 /* Emulate the instruction in the opcode. */
  97 unsigned int EmulateAll(unsigned int opcode)
  98 {
  99         unsigned int code;
 100
 101 #ifdef NWFPE_DEBUG
 102         printk("NWFPE: emulating opcode %08x\n", opcode);
 103 #endif
 104         code = opcode & 0x00000f00;
 105         if (code == 0x00000100 || code == 0x00000200) {
 106                 /* For coprocessor 1 or 2 (FPA11) */
 107                 code = opcode & 0x0e000000;
 108                 if (code == 0x0e000000) {
 109                         if (opcode & 0x00000010) {
 110                                 /* Emulate conversion opcodes. */
 111                                 /* Emulate register transfer opcodes. */
 112                                 /* Emulate comparison opcodes. */
 113                                 return EmulateCPRT(opcode);
 114                         } else {
 115                                 /* Emulate monadic arithmetic opcodes. */
 116                                 /* Emulate dyadic arithmetic opcodes. */
 117                                 return EmulateCPDO(opcode);
 118                         }
 119                 } else if (code == 0x0c000000) {
 120                         /* Emulate load/store opcodes. */
 121                         /* Emulate load/store multiple opcodes. */
 122                         return EmulateCPDT(opcode);
 123                 }
 124         }
 125
 126         /* Invalid instruction detected.  Return FALSE. */
 127         return 0;
 128 }