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 /* Reset the FPA11 chip.  Called to initialize and reset the emulator. */
  35 static void resetFPA11(void)
  36 {
  37         int i;
  38         FPA11 *fpa11 = GET_FPA11();
  39
  40         /* initialize the register type array */
  41         for (i = 0; i <= 7; i++) {
  42                 fpa11->fType[i] = typeNone;
  43         }
  44
  45         /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
  46         fpa11->fpsr = FP_EMULATOR | BIT_AC;
  47 }
  48
  49 int8 SetRoundingMode(const unsigned int opcode)
  50 {
  51         switch (opcode & MASK_ROUNDING_MODE) {
  52         default:
  53         case ROUND_TO_NEAREST:
  54                 return float_round_nearest_even;
  55
  56         case ROUND_TO_PLUS_INFINITY:
  57                 return float_round_up;
  58
  59         case ROUND_TO_MINUS_INFINITY:
  60                 return float_round_down;
  61
  62         case ROUND_TO_ZERO:
  63                 return float_round_to_zero;
  64         }
  65 }
  66
  67 int8 SetRoundingPrecision(const unsigned int opcode)
  68 {
  69 #ifdef CONFIG_FPE_NWFPE_XP
  70         switch (opcode & MASK_ROUNDING_PRECISION) {
  71         case ROUND_SINGLE:
  72                 return 32;
  73
  74         case ROUND_DOUBLE:
  75                 return 64;
  76
  77         case ROUND_EXTENDED:
  78                 return 80;
  79
  80         default:
  81                 return 80;
  82         }
  83 #endif
  84         return 80;
  85 }
  86
  87 void nwfpe_init_fpa(union fp_state *fp)
  88 {
  89         FPA11 *fpa11 = (FPA11 *)fp;
  90 #ifdef NWFPE_DEBUG
  91         printk("NWFPE: setting up state.\n");
  92 #endif
  93         memset(fpa11, 0, sizeof(FPA11));
  94         resetFPA11();
  95         fpa11->initflag = 1;
  96 }
  97
  98 /* Emulate the instruction in the opcode. */
  99 unsigned int EmulateAll(unsigned int opcode)
 100 {
 101         unsigned int code;
 102
 103 #ifdef NWFPE_DEBUG
 104         printk("NWFPE: emulating opcode %08x\n", opcode);
 105 #endif
 106         code = opcode & 0x00000f00;
 107         if (code == 0x00000100 || code == 0x00000200) {
 108                 /* For coprocessor 1 or 2 (FPA11) */
 109                 code = opcode & 0x0e000000;
 110                 if (code == 0x0e000000) {
 111                         if (opcode & 0x00000010) {
 112                                 /* Emulate conversion opcodes. */
 113                                 /* Emulate register transfer opcodes. */
 114                                 /* Emulate comparison opcodes. */
 115                                 return EmulateCPRT(opcode);
 116                         } else {
 117                                 /* Emulate monadic arithmetic opcodes. */
 118                                 /* Emulate dyadic arithmetic opcodes. */
 119                                 return EmulateCPDO(opcode);
 120                         }
 121                 } else if (code == 0x0c000000) {
 122                         /* Emulate load/store opcodes. */
 123                         /* Emulate load/store multiple opcodes. */
 124                         return EmulateCPDT(opcode);
 125                 }
 126         }
 127
 128         /* Invalid instruction detected.  Return FALSE. */
 129         return 0;
 130 }