sdk/lib/fast486/fpu.h

   1 /*
   2  * Fast486 386/486 CPU Emulation Library
   3  * fpu.h
   4  *
   5  * Copyright (C) 2015 Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20  */
  21
  22 #ifndef _FPU_H_
  23 #define _FPU_H_
  24
  25 #pragma once
  26
  27 #include "opcodes.h"
  28
  29 /* DEFINES ********************************************************************/
  30
  31 #define FPU_CHECK() if (State->ControlRegisters[FAST486_REG_CR0] & (FAST486_CR0_EM | FAST486_CR0_TS)) \
  32                     { \
  33                         Fast486Exception(State, FAST486_EXCEPTION_NM); \
  34                         return; \
  35                     }
  36 #define FPU_INDEX(i) ((State->FpuStatus.Top + (i)) % FAST486_NUM_FPU_REGS)
  37 #define FPU_ST(i)   State->FpuRegisters[FPU_INDEX(i)]
  38
  39 #define FPU_GET_TAG(i)      ((State->FpuTag >> (FPU_INDEX(i) * 2)) & 3)
  40 #define FPU_SET_TAG(i, t)   { \
  41                                 State->FpuTag &= ~((1 << (FPU_INDEX(i) * 2)) | (1 << ((FPU_INDEX(i) * 2) + 1))); \
  42                                 State->FpuTag |= ((t) & 3) << (FPU_INDEX(i) * 2); \
  43                             }
  44 #define FPU_UPDATE_TAG(i)   FPU_SET_TAG((i), Fast486FpuGetValueTag(&FPU_ST(i)))
  45 #define FPU_SAVE_LAST_INST()    { \
  46                                     State->FpuLastInstPtr = State->SavedInstPtr; \
  47                                     State->FpuLastCodeSel = State->SegmentRegs[FAST486_REG_CS].Selector; \
  48                                 }
  49 #define FPU_SAVE_LAST_OPERAND() { \
  50                                     State->FpuLastOpPtr.Long = ModRegRm.MemoryAddress; \
  51                                     State->FpuLastDataSel = (State->PrefixFlags & FAST486_PREFIX_SEG) \
  52                                                             ? State->SegmentOverride : FAST486_REG_DS; \
  53                                 }
  54
  55 #define FPU_REAL4_BIAS          0x7F
  56 #define FPU_REAL8_BIAS          0x3FF
  57 #define FPU_REAL10_BIAS         0x3FFF
  58 #define FPU_MAX_EXPONENT        0x7FFE
  59 #define FPU_MANTISSA_HIGH_BIT   0x8000000000000000ULL
  60 #define FPU_INDEFINITE_MANTISSA 0xC000000000000000ULL
  61 #define FPU_REAL4_INFINITY      0x7F800000
  62 #define FPU_REAL4_INDEFINITE    0xFFC00000
  63 #define FPU_REAL8_INFINITY      0x7FF0000000000000ULL
  64 #define FPU_REAL8_INDEFINITE    0xFFF8000000000000ULL
  65
  66 #define FPU_IS_NORMALIZED(x)    (FPU_IS_ZERO(x) || (((x)->Mantissa & FPU_MANTISSA_HIGH_BIT) != 0ULL))
  67 #define FPU_IS_ZERO(x)          ((x)->Mantissa == 0ULL)
  68 #define FPU_IS_NAN(x)           ((x)->Exponent == (FPU_MAX_EXPONENT + 1))
  69 #define FPU_IS_INFINITY(x)      (FPU_IS_NAN(x) && ((x)->Mantissa == FPU_MANTISSA_HIGH_BIT))
  70 #define FPU_IS_POS_INF(x)       (FPU_IS_INFINITY(x) && !(x)->Sign)
  71 #define FPU_IS_NEG_INF(x)       (FPU_IS_INFINITY(x) && (x)->Sign)
  72 #define FPU_IS_INDEFINITE(x)    (FPU_IS_NAN(x) && !FPU_IS_INFINITY(x))
  73
  74 #define INVERSE_NUMBERS_COUNT   50
  75
  76 enum
  77 {
  78     FPU_SINGLE_PRECISION = 0,
  79     FPU_DOUBLE_PRECISION = 2,
  80     FPU_DOUBLE_EXT_PRECISION = 3
  81 };
  82
  83 enum
  84 {
  85     FPU_TAG_VALID = 0,
  86     FPU_TAG_ZERO = 1,
  87     FPU_TAG_SPECIAL = 2,
  88     FPU_TAG_EMPTY = 3
  89 };
  90
  91 enum
  92 {
  93     FPU_ROUND_NEAREST = 0,
  94     FPU_ROUND_DOWN = 1,
  95     FPU_ROUND_UP = 2,
  96     FPU_ROUND_TRUNCATE = 3
  97 };
  98
  99 FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD8);
 100 FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD9);
 101 FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDA);
 102 FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDB);
 103 FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDC);
 104 FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDD);
 105 FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDE);
 106 FAST486_OPCODE_HANDLER(Fast486FpuOpcodeDF);
 107
 108 #endif // _FPU_H_
 109
 110 /* EOF */