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 #include <asm/system.h>
  32
  33 /* Reset the FPA11 chip.  Called to initialize and reset the emulator. */
  34 static void resetFPA11(void)
  35 {
  36         int i;
  37         FPA11 *fpa11 = GET_FPA11();
  38
  39         /* initialize the register type array */
  40         for (i = 0; i <= 7; i++) {
  41                 fpa11->fType[i] = typeNone;
  42         }
  43
  44         /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
  45         fpa11->fpsr = FP_EMULATOR | BIT_AC;
  46 }
  47
  48 int8 SetRoundingMode(const unsigned int opcode)
  49 {
  50         switch (opcode & MASK_ROUNDING_MODE) {
  51         default:
  52         case ROUND_TO_NEAREST:
  53                 return float_round_nearest_even;
  54
  55         case ROUND_TO_PLUS_INFINITY:
  56                 return float_round_up;
  57
  58         case ROUND_TO_MINUS_INFINITY:
  59                 return float_round_down;
  60
  61         case ROUND_TO_ZERO:
  62                 return float_round_to_zero;
  63         }
  64 }
  65
  66 int8 SetRoundingPrecision(const unsigned int opcode)
  67 {
  68 #ifdef CONFIG_FPE_NWFPE_XP
  69         switch (opcode & MASK_ROUNDING_PRECISION) {
  70         case ROUND_SINGLE:
  71                 return 32;
  72
  73         case ROUND_DOUBLE:
  74                 return 64;
  75
  76         case ROUND_EXTENDED:
  77                 return 80;
  78
  79         default:
  80                 return 80;
  81         }
  82 #endif
  83         return 80;
  84 }
  85
  86 void nwfpe_init_fpa(union fp_state *fp)
  87 {
  88         FPA11 *fpa11 = (FPA11 *)fp;
  89 #ifdef NWFPE_DEBUG
  90         printk("NWFPE: setting up state.\n");
  91 #endif
  92         memset(fpa11, 0, sizeof(FPA11));
  93         resetFPA11();
  94         fpa11->initflag = 1;
  95 }
  96
  97 /* Emulate the instruction in the opcode. */
  98 unsigned int EmulateAll(unsigned int opcode)
  99 {
 100         unsigned int code;
 101
 102 #ifdef NWFPE_DEBUG
 103         printk("NWFPE: emulating opcode %08x\n", opcode);
 104 #endif
 105         code = opcode & 0x00000f00;
 106         if (code == 0x00000100 || code == 0x00000200) {
 107                 /* For coprocessor 1 or 2 (FPA11) */
 108                 code = opcode & 0x0e000000;
 109                 if (code == 0x0e000000) {
 110                         if (opcode & 0x00000010) {
 111                                 /* Emulate conversion opcodes. */
 112                                 /* Emulate register transfer opcodes. */
 113                                 /* Emulate comparison opcodes. */
 114                                 return EmulateCPRT(opcode);
 115                         } else {
 116                                 /* Emulate monadic arithmetic opcodes. */
 117                                 /* Emulate dyadic arithmetic opcodes. */
 118                                 return EmulateCPDO(opcode);
 119                         }
 120                 } else if (code == 0x0c000000) {
 121                         /* Emulate load/store opcodes. */
 122                         /* Emulate load/store multiple opcodes. */
 123                         return EmulateCPDT(opcode);
 124                 }
 125         }
 126
 127         /* Invalid instruction detected.  Return FALSE. */
 128         return 0;
 129 }