cpu.cpp

著名SFC模拟器Snes9x的源代码。

/*
 * Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 *
 * (c) Copyright 1996 - 2001 Gary Henderson ([e-mail]) and
 *                           Jerremy Koot ([e-mail])
 *
 * Super FX C emulator code 
 * (c) Copyright 1997 - 1999 Ivar ([e-mail]) and
 *                           Gary Henderson.
 * Super FX assembler emulator code (c) Copyright 1998 zsKnight and _Demo_.
 *
 * DSP1 emulator code (c) Copyright 1998 Ivar, _Demo_ and Gary Henderson.
 * C4 asm and some C emulation code (c) Copyright 2000 zsKnight and _Demo_.
 * C4 C code (c) Copyright 2001 Gary Henderson ([e-mail]).
 *
 * DOS port code contains the works of other authors. See headers in
 * individual files.
 *
 * Snes9x homepage: www.snes9x.com
 *
 * Permission to use, copy, modify and distribute Snes9x in both binary and
 * source form, for non-commercial purposes, is hereby granted without fee,
 * providing that this license information and copyright notice appear with
 * all copies and any derived work.
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event shall the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Snes9x is freeware for PERSONAL USE only. Commercial users should
 * seek permission of the copyright holders first. Commercial use includes
 * charging money for Snes9x or software derived from Snes9x.
 *
 * The copyright holders request that bug fixes and improvements to the code
 * should be forwarded to them so everyone can benefit from the modifications
 * in future versions.
 *
 * Super NES and Super Nintendo Entertainment System are trademarks of
 * Nintendo Co., Limited and its subsidiary companies.
 */
#include "snes9x.h"
#include "memmap.h"
#include "ppu.h"
#include "dsp1.h"
#include "cpuexec.h"
#include "debug.h"
#include "apu.h"
#include "dma.h"
#include "sa1.h"
#include "cheats.h"
#include "srtc.h"

#ifndef ZSNES_FX
#include "fxemu.h"

extern struct FxInit_s SuperFX;

void S9xResetSuperFX ()
{
    SuperFX.vFlags = 0; //FX_FLAG_ROM_BUFFER;// | FX_FLAG_ADDRESS_CHECKING;
    FxReset (&SuperFX);
}
#endif

void S9xResetCPU ()
{
    Registers.PB = 0;
    Registers.PC = S9xGetWord (0xFFFC);
    Registers.D.W = 0;
    Registers.DB = 0;
    Registers.SH = 1;
    Registers.SL = 0xFF;
    Registers.XH = 0;
    Registers.YH = 0;
    Registers.P.W = 0;

    ICPU.ShiftedPB = 0;
    ICPU.ShiftedDB = 0;
    SetFlags (MemoryFlag | IndexFlag | IRQ | Emulation);
    ClearFlags (Decimal);

    CPU.Flags = CPU.Flags & (DEBUG_MODE_FLAG | TRACE_FLAG);
    CPU.BranchSkip = FALSE;
    CPU.NMIActive = FALSE;
    CPU.IRQActive = FALSE;
    CPU.WaitingForInterrupt = FALSE;
    CPU.InDMA = FALSE;
    CPU.WhichEvent = HBLANK_START_EVENT;
    CPU.PC = NULL;
    CPU.PCBase = NULL;
    CPU.PCAtOpcodeStart = NULL;
    CPU.WaitAddress = NULL;
    CPU.WaitCounter = 0;
    CPU.Cycles = 0;
    CPU.NextEvent = Settings.HBlankStart;
    CPU.V_Counter = 0;
    CPU.MemSpeed = 8;
    CPU.MemSpeedx2 = 16;
    CPU.FastROMSpeed = 8;
    CPU.AutoSaveTimer = 0;
    CPU.SRAMModified = FALSE;
    // CPU.NMITriggerPoint = 4; // Set when ROM image loaded
    CPU.BRKTriggered = FALSE;
    //CPU.TriedInterleavedMode2 = FALSE; // Reset when ROM image loaded
    CPU.NMICycleCount = 0;
    CPU.IRQCycleCount = 0;
    S9xSetPCBase (Registers.PC);

#ifndef VAR_CYCLES
    ICPU.Speed = S9xE1M1X1;
#endif
    ICPU.S9xOpcodes = S9xOpcodesM1X1;
    ICPU.CPUExecuting = TRUE;

    S9xUnpackStatus();
}

#ifdef ZSNES_FX
START_EXTERN_C
void S9xResetSuperFX ();
bool8 WinterGold = 0;
extern uint8 *C4Ram;
END_EXTERN_C
#endif

void S9xReset (void)
{
    if (Settings.SuperFX)
	S9xResetSuperFX ();

#ifdef ZSNES_FX
    WinterGold = Settings.WinterGold;
#endif
    ZeroMemory (Memory.FillRAM, 0x8000);
    memset (Memory.VRAM, 0x00, 0x10000);
    memset (Memory.RAM, 0x55, 0x20000);

    S9xResetCPU ();
    S9xResetPPU ();
    S9xResetSRTC ();

    S9xResetDMA ();
    S9xResetAPU ();
    S9xResetDSP1 ();
    S9xSA1Init ();
    if (Settings.C4)
	S9xInitC4 ();
    S9xInitCheatData ();

    Settings.Paused = FALSE;
}