/* @(#) $Id: CpuModule_InternalState.c,v 1.9 2012-08-12 16:51:02 peschau Exp $ */
/*=========================================================================*/
/* Fellow                                                                  */
/* 68000 internal state                                                    */
/*                                                                         */
/* Author: Petter Schau                                                    */
/*                                                                         */
/* Copyright (C) 1991, 1992, 1996 Free Software Foundation, Inc.           */
/*                                                                         */
/* 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, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.          */
/*=========================================================================*/
#include "defs.h"
#include "CpuModule.h"
#include "fellow.h"
#include "fmem.h"
#include "CpuModule_Internal.h"

/* M68k registers */
static ULO cpu_regs[2][8]; /* 0 - data, 1 - address */
static ULO cpu_pc;
static ULO cpu_usp;
static ULO cpu_ssp;
static ULO cpu_msp;
static ULO cpu_sfc;
static ULO cpu_dfc;
ULO cpu_sr; // Not static because flags calculation use it extensively
static ULO cpu_vbr;
static UWO cpu_prefetch_word;
static ULO cpu_cacr;
static ULO cpu_caar;

/* Irq management */
static BOOLE cpu_raise_irq;
static ULO cpu_raise_irq_level;

/* Reset values */
static ULO cpu_initial_pc;
static ULO cpu_initial_sp;

/* Flag set if CPU is stopped */
static BOOLE cpu_stop;

/* The current CPU model */
static ULO cpu_model_major = -1;
static ULO cpu_model_minor;
static UBY cpu_model_mask;

/* For exception handling */
#ifdef CPU_INSTRUCTION_LOGGING

static UWO cpu_current_opcode;

#endif

static ULO cpu_original_pc;

/* Number of cycles taken by the last intstruction */
static ULO cpu_instruction_time;

/* Getters and setters */

void cpuSetDReg(ULO i, ULO value) {cpu_regs[0][i] = value;}
ULO cpuGetDReg(ULO i) {return cpu_regs[0][i];}

void cpuSetAReg(ULO i, ULO value) {cpu_regs[1][i] = value;}
ULO cpuGetAReg(ULO i) {return cpu_regs[1][i];}

void cpuSetReg(ULO da, ULO i, ULO value) {cpu_regs[da][i] = value;}
ULO cpuGetReg(ULO da, ULO i) {return cpu_regs[da][i];}

/// <summary>
/// Get the supervisor bit from sr.
/// </summary>
BOOLE cpuGetFlagSupervisor(void)
{
  return cpu_sr & 0x2000;
}

/// <summary>
/// Get the master/irq state bit from sr.
/// </summary>
BOOLE cpuGetFlagMaster(void)
{
  return cpu_sr & 0x1000;
}

void cpuSetUspDirect(ULO usp) {cpu_usp = usp;}
ULO cpuGetUspDirect(void) {return cpu_usp;}
ULO cpuGetUspAutoMap(void) {return (cpuGetFlagSupervisor()) ? cpuGetUspDirect() : cpuGetAReg(7);}

void cpuSetSspDirect(ULO ssp) {cpu_ssp = ssp;}
ULO cpuGetSspDirect(void) {return cpu_ssp;}
ULO cpuGetSspAutoMap(void) {return (cpuGetFlagSupervisor()) ? cpuGetAReg(7) : cpuGetSspDirect();}

void cpuSetMspDirect(ULO msp) {cpu_msp = msp;}
ULO cpuGetMspDirect(void) {return cpu_msp;}

/// <summary>
/// Returns the master stack pointer.
/// </summary>
ULO cpuGetMspAutoMap(void)
{
  if (cpuGetFlagSupervisor() && cpuGetFlagMaster())
  {
    return cpuGetAReg(7);
  }
  return cpuGetMspDirect();
}
    
/// <summary>
/// Sets the master stack pointer.
/// </summary>
void cpuSetMspAutoMap(ULO new_msp)
{
  if (cpuGetFlagSupervisor() && cpuGetFlagMaster())
  {
    cpuSetAReg(7, new_msp);
  }
  else
  {
    cpuSetMspDirect(new_msp);
  }
}
    
/// <summary>
/// Returns the interrupt stack pointer. ssp is used as isp.
/// </summary>
ULO cpuGetIspAutoMap(void)
{
  if (cpuGetFlagSupervisor() && !cpuGetFlagMaster())
  {
    return cpuGetAReg(7);
  }
  return cpuGetSspDirect();
}
    
/// <summary>
/// Sets the interrupt stack pointer. ssp is used as isp.
/// </summary>
void cpuSetIspAutoMap(ULO new_isp)
{
  if (cpuGetFlagSupervisor() && !cpuGetFlagMaster())
  {
    cpuSetAReg(7, new_isp);
  }
  else
  {
    cpuSetSspDirect(new_isp);
  }
}

void cpuSetPC(ULO address) {cpu_pc = address;}
ULO cpuGetPC(void) {return cpu_pc;}

void cpuSetStop(BOOLE stop) {cpu_stop = stop;}
BOOLE cpuGetStop(void) {return cpu_stop;}

void cpuSetVbr(ULO vbr) {cpu_vbr = vbr;}
ULO cpuGetVbr(void) {return cpu_vbr;}

void cpuSetSfc(ULO sfc) {cpu_sfc = sfc;}
ULO cpuGetSfc(void) {return cpu_sfc;}

void cpuSetDfc(ULO dfc) {cpu_dfc = dfc;}
ULO cpuGetDfc(void) {return cpu_dfc;}

void cpuSetCacr(ULO cacr) {cpu_cacr = cacr;}
ULO cpuGetCacr(void) {return cpu_cacr;}

void cpuSetCaar(ULO caar) {cpu_caar = caar;}
ULO cpuGetCaar(void) {return cpu_caar;}

void cpuSetSR(ULO sr) {cpu_sr = sr;}
ULO cpuGetSR(void) {return cpu_sr;}

void cpuSetInstructionTime(ULO cycles) {cpu_instruction_time = cycles;}
ULO cpuGetInstructionTime(void) {return cpu_instruction_time;}

void cpuSetOriginalPC(ULO pc) {cpu_original_pc = pc;}
ULO cpuGetOriginalPC(void) {return cpu_original_pc;}

#ifdef CPU_INSTRUCTION_LOGGING

void cpuSetCurrentOpcode(UWO opcode) {cpu_current_opcode = opcode;}
UWO cpuGetCurrentOpcode(void) {return cpu_current_opcode;}

#endif

void cpuSetRaiseInterrupt(BOOLE raise_irq) {cpu_raise_irq = raise_irq;}
BOOLE cpuGetRaiseInterrupt(void) {return cpu_raise_irq;}
void cpuSetRaiseInterruptLevel(ULO raise_irq_level) {cpu_raise_irq_level = raise_irq_level;}
ULO cpuGetRaiseInterruptLevel(void) {return cpu_raise_irq_level;}

ULO cpuGetIrqLevel(void) {return (cpu_sr & 0x0700) >> 8;}

void cpuSetInitialPC(ULO pc) {cpu_initial_pc = pc;}
ULO cpuGetInitialPC(void) {return cpu_initial_pc;}

void cpuSetInitialSP(ULO sp) {cpu_initial_sp = sp;}
ULO cpuGetInitialSP(void) {return cpu_initial_sp;}

void cpuSetModelMask(UBY model_mask) {cpu_model_mask = model_mask;}
UBY cpuGetModelMask(void) {return cpu_model_mask;}

ULO cpuGetModelMajor(void) {return cpu_model_major;}
ULO cpuGetModelMinor(void) {return cpu_model_minor;}

static void cpuCalculateModelMask(void)
{
  switch (cpuGetModelMajor())
  {
    case 0:
      cpuSetModelMask(0x01);
      break;
    case 1:
      cpuSetModelMask(0x02);
      break;
    case 2:
      cpuSetModelMask(0x04);
      break;
    case 3:
      cpuSetModelMask(0x08);
      break;
  }
}

void cpuSetModel(ULO major, ULO minor)
{
  BOOLE makeOpcodeTable = (cpu_model_major != major);
  cpu_model_major = major;
  cpu_model_minor = minor;
  cpuCalculateModelMask();
  cpuStackFrameInit();
  if (makeOpcodeTable) cpuMakeOpcodeTableForModel();
}

void cpuSetDRegWord(ULO regno, UWO val) {*((WOR*)&cpu_regs[0][regno]) = val;}
void cpuSetDRegByte(ULO regno, UBY val) {*((UBY*)&cpu_regs[0][regno]) = val;}
UWO cpuGetRegWord(ULO i, ULO regno) {return (UWO)cpu_regs[i][regno];}

UWO cpuGetDRegWord(ULO regno) {return (UWO)cpu_regs[0][regno];}
UBY cpuGetDRegByte(ULO regno) {return (UBY)cpu_regs[0][regno];}

ULO cpuGetDRegWordSignExtLong(ULO regno) {return cpuSignExtWordToLong(cpuGetDRegWord(regno));}
UWO cpuGetDRegByteSignExtWord(ULO regno) {return cpuSignExtByteToWord(cpuGetDRegByte(regno));}
ULO cpuGetDRegByteSignExtLong(ULO regno) {return cpuSignExtByteToLong(cpuGetDRegByte(regno));}

UWO cpuGetARegWord(ULO regno) {return (UWO)cpu_regs[1][regno];}
UBY cpuGetARegByte(ULO regno) {return (UBY)cpu_regs[1][regno];}

typedef UWO (*cpuGetWordFunc)(void);
typedef ULO (*cpuGetLongFunc)(void);

static UWO cpuGetNextWordInternal(void)
{
  UWO data = memoryReadWord(cpuGetPC() + 2);
  return data;
}

static ULO cpuGetNextLongInternal(void)
{
  ULO data = memoryReadLong(cpuGetPC() + 2);
  return data;
}

UWO cpuGetNextWord(void)
{
  UWO tmp = cpu_prefetch_word;
  cpu_prefetch_word = cpuGetNextWordInternal();
  cpuSetPC(cpuGetPC() + 2);
  return tmp;
}

ULO cpuGetNextWordSignExt(void)
{
  return cpuSignExtWordToLong(cpuGetNextWord());
}

ULO cpuGetNextLong(void)
{
  ULO tmp = cpu_prefetch_word << 16;
  ULO data = cpuGetNextLongInternal();
  cpu_prefetch_word = (UWO) data;
  cpuSetPC(cpuGetPC() + 4);
  return tmp | (data >> 16);
}

void cpuInitializePrefetch(void)
{
  cpu_prefetch_word = memoryReadWord(cpuGetPC());
}

void cpuClearPrefetch(void)
{
  cpu_prefetch_word = 0;
}

void cpuSkipNextWord(void)
{
  cpuSetPC(cpuGetPC() + 2);
  cpuInitializePrefetch();
}

void cpuSkipNextLong(void)
{
  cpuSetPC(cpuGetPC() + 4);
  cpuInitializePrefetch();
}

void cpuInitializeFromNewPC(ULO new_pc)
{
  cpuSetPC(new_pc);
  cpuInitializePrefetch();
}

void cpuSaveState(FILE *F)
{
  ULO i, j;

  fwrite(&cpu_model_major, sizeof(cpu_model_major), 1, F);
  fwrite(&cpu_model_minor, sizeof(cpu_model_minor), 1, F);
  for (i = 0; i < 2; i++)
  {
    for (j = 0; j < 7; j++)
    {
      fwrite(&cpu_regs[i][j], sizeof(cpu_regs[i][j]), 1, F);
    }
  }
  fwrite(&cpu_pc, sizeof(cpu_pc), 1, F);
  fwrite(&cpu_usp, sizeof(cpu_usp), 1, F);
  fwrite(&cpu_ssp, sizeof(cpu_ssp), 1, F);
  fwrite(&cpu_msp, sizeof(cpu_msp), 1, F);
  fwrite(&cpu_sfc, sizeof(cpu_sfc), 1, F);
  fwrite(&cpu_dfc, sizeof(cpu_dfc), 1, F);
  fwrite(&cpu_sr, sizeof(cpu_sr), 1, F);
  fwrite(&cpu_prefetch_word, sizeof(cpu_prefetch_word), 1, F);
  fwrite(&cpu_vbr, sizeof(cpu_vbr), 1, F);
  fwrite(&cpu_cacr, sizeof(cpu_cacr), 1, F);
  fwrite(&cpu_caar, sizeof(cpu_caar), 1, F);
  fwrite(&cpu_initial_pc, sizeof(cpu_initial_pc), 1, F);
  fwrite(&cpu_initial_sp, sizeof(cpu_initial_sp), 1, F);
}

void cpuLoadState(FILE *F)
{
  ULO i, j;

  fread(&cpu_model_major, sizeof(cpu_model_major), 1, F);
  fread(&cpu_model_minor, sizeof(cpu_model_minor), 1, F);
  for (i = 0; i < 2; i++)
  {
    for (j = 0; j < 7; j++)
    {
      fread(&cpu_regs[i][j], sizeof(cpu_regs[i][j]), 1, F);
    }
  }
  fread(&cpu_pc, sizeof(cpu_pc), 1, F);
  fread(&cpu_usp, sizeof(cpu_usp), 1, F);
  fread(&cpu_ssp, sizeof(cpu_ssp), 1, F);
  fread(&cpu_msp, sizeof(cpu_msp), 1, F);
  fread(&cpu_sfc, sizeof(cpu_sfc), 1, F);
  fread(&cpu_dfc, sizeof(cpu_dfc), 1, F);
  fread(&cpu_sr, sizeof(cpu_sr), 1, F);
  fread(&cpu_prefetch_word, sizeof(cpu_prefetch_word), 1, F);
  fread(&cpu_vbr, sizeof(cpu_vbr), 1, F);
  fread(&cpu_cacr, sizeof(cpu_cacr), 1, F);
  fread(&cpu_caar, sizeof(cpu_caar), 1, F);
  fread(&cpu_initial_pc, sizeof(cpu_initial_pc), 1, F);
  fread(&cpu_initial_sp, sizeof(cpu_initial_sp), 1, F);
  cpuSetModel(cpu_model_major, cpu_model_minor); // Recalculates stack frames etc.
}