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fpa11.c

/*
    NetWinder Floating Point Emulator
    (c) Rebel.COM, 1998,1999
    (c) Philip Blundell, 2001

    Direct questions, comments to Scott Bambrough <scottb@netwinder.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "fpa11.h"
#include "fpopcode.h"

#include "fpmodule.h"
#include "fpmodule.inl"

#include <linux/compiler.h>
#include <linux/string.h>
#include <asm/system.h>

/* Reset the FPA11 chip.  Called to initialize and reset the emulator. */
static void resetFPA11(void)
{
      int i;
      FPA11 *fpa11 = GET_FPA11();

      /* initialize the register type array */
      for (i = 0; i <= 7; i++) {
            fpa11->fType[i] = typeNone;
      }

      /* FPSR: set system id to FP_EMULATOR, set AC, clear all other bits */
      fpa11->fpsr = FP_EMULATOR | BIT_AC;
}

int8 SetRoundingMode(const unsigned int opcode)
{
      switch (opcode & MASK_ROUNDING_MODE) {
      default:
      case ROUND_TO_NEAREST:
            return float_round_nearest_even;

      case ROUND_TO_PLUS_INFINITY:
            return float_round_up;

      case ROUND_TO_MINUS_INFINITY:
            return float_round_down;

      case ROUND_TO_ZERO:
            return float_round_to_zero;
      }
}

int8 SetRoundingPrecision(const unsigned int opcode)
{
#ifdef CONFIG_FPE_NWFPE_XP
      switch (opcode & MASK_ROUNDING_PRECISION) {
      case ROUND_SINGLE:
            return 32;

      case ROUND_DOUBLE:
            return 64;

      case ROUND_EXTENDED:
            return 80;

      default:
            return 80;
      }
#endif
      return 80;
}

void nwfpe_init_fpa(union fp_state *fp)
{
      FPA11 *fpa11 = (FPA11 *)fp;
#ifdef NWFPE_DEBUG
      printk("NWFPE: setting up state.\n");
#endif
      memset(fpa11, 0, sizeof(FPA11));
      resetFPA11();
      fpa11->initflag = 1;
}

/* Emulate the instruction in the opcode. */
unsigned int EmulateAll(unsigned int opcode)
{
      unsigned int code;

#ifdef NWFPE_DEBUG
      printk("NWFPE: emulating opcode %08x\n", opcode);
#endif
      code = opcode & 0x00000f00;
      if (code == 0x00000100 || code == 0x00000200) {
            /* For coprocessor 1 or 2 (FPA11) */
            code = opcode & 0x0e000000;
            if (code == 0x0e000000) {
                  if (opcode & 0x00000010) {
                        /* Emulate conversion opcodes. */
                        /* Emulate register transfer opcodes. */
                        /* Emulate comparison opcodes. */
                        return EmulateCPRT(opcode);
                  } else {
                        /* Emulate monadic arithmetic opcodes. */
                        /* Emulate dyadic arithmetic opcodes. */
                        return EmulateCPDO(opcode);
                  }
            } else if (code == 0x0c000000) {
                  /* Emulate load/store opcodes. */
                  /* Emulate load/store multiple opcodes. */
                  return EmulateCPDT(opcode);
            }
      }

      /* Invalid instruction detected.  Return FALSE. */
      return 0;
}

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