fpu.h

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/*
 * Fast486 386/486 CPU Emulation Library
 * fpu.h
 *
 * Copyright (C) 2015 Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#ifndef _FPU_H_
#define _FPU_H_

#pragma once

#include "opcodes.h"

/* DEFINES ********************************************************************/

#define FPU_CHECK() if (State->ControlRegisters[FAST486_REG_CR0] & (FAST486_CR0_EM | FAST486_CR0_TS)) \
                    { \
                        Fast486Exception(State, FAST486_EXCEPTION_NM); \
                        return; \
                    }
#define FPU_INDEX(i) ((State->FpuStatus.Top + (i)) % FAST486_NUM_FPU_REGS)
#define FPU_ST(i)   State->FpuRegisters[FPU_INDEX(i)]

#define FPU_GET_TAG(i)      ((State->FpuTag >> (FPU_INDEX(i) * 2)) & 3)
#define FPU_SET_TAG(i, t)   { \
                                State->FpuTag &= ~((1 << (FPU_INDEX(i) * 2)) | (1 << ((FPU_INDEX(i) * 2) + 1))); \
                                State->FpuTag |= ((t) & 3) << (FPU_INDEX(i) * 2); \
                            }
#define FPU_UPDATE_TAG(i)   FPU_SET_TAG((i), Fast486FpuGetValueTag(&FPU_ST(i)))
#define FPU_SAVE_LAST_INST()    { \
                                    State->FpuLastInstPtr = State->SavedInstPtr; \
                                    State->FpuLastCodeSel = State->SegmentRegs[FAST486_REG_CS].Selector; \
                                }
#define FPU_SAVE_LAST_OPERAND() { \
                                    State->FpuLastOpPtr.Long = ModRegRm.MemoryAddress; \
                                    State->FpuLastDataSel = (State->PrefixFlags & FAST486_PREFIX_SEG) \
                                                            ? State->SegmentOverride : FAST486_REG_DS; \
                                }

#define FPU_REAL4_BIAS          0x7F
#define FPU_REAL8_BIAS          0x3FF
#define FPU_REAL10_BIAS         0x3FFF
#define FPU_MAX_EXPONENT        0x7FFE
#define FPU_MANTISSA_HIGH_BIT   0x8000000000000000ULL
#define FPU_INDEFINITE_MANTISSA 0xC000000000000000ULL
#define FPU_REAL4_INFINITY      0x7F800000
#define FPU_REAL4_INDEFINITE    0xFFC00000
#define FPU_REAL8_INFINITY      0x7FF0000000000000ULL
#define FPU_REAL8_INDEFINITE    0xFFF8000000000000ULL

#define FPU_IS_NORMALIZED(x)    (FPU_IS_ZERO(x) || (((x)->Mantissa & FPU_MANTISSA_HIGH_BIT) != 0ULL))
#define FPU_IS_ZERO(x)          ((x)->Mantissa == 0ULL)
#define FPU_IS_NAN(x)           ((x)->Exponent == (FPU_MAX_EXPONENT + 1))
#define FPU_IS_INFINITY(x)      (FPU_IS_NAN(x) && ((x)->Mantissa == FPU_MANTISSA_HIGH_BIT))
#define FPU_IS_POS_INF(x)       (FPU_IS_INFINITY(x) && !(x)->Sign)
#define FPU_IS_NEG_INF(x)       (FPU_IS_INFINITY(x) && (x)->Sign)
#define FPU_IS_INDEFINITE(x)    (FPU_IS_NAN(x) && !FPU_IS_INFINITY(x))

#define INVERSE_NUMBERS_COUNT   50

enum
{
    FPU_SINGLE_PRECISION = 0,
    FPU_DOUBLE_PRECISION = 2,
    FPU_DOUBLE_EXT_PRECISION = 3
};

enum
{
    FPU_TAG_VALID = 0,
    FPU_TAG_ZERO = 1,
    FPU_TAG_SPECIAL = 2,
    FPU_TAG_EMPTY = 3
};

enum
{
    FPU_ROUND_NEAREST = 0,
    FPU_ROUND_DOWN = 1,
    FPU_ROUND_UP = 2,
    FPU_ROUND_TRUNCATE = 3
};

FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD8);
FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD9);
FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDA);
FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDB);
FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDC);
FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDD);
FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDE);
FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDF);

#endif // _FPU_H_

/* EOF */