cheats.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 <stdio.h>
#include <ctype.h>
#include <string.h>
#include "snes9x.h"
#include "cheats.h"
#include "memmap.h"

static bool8 S9xAllHex (const char *code, int len)
{
    for (int i = 0; i < len; i++)
        if ((code [i] < '0' || code [i] > '9') &&
            (code [i] < 'a' || code [i] > 'f') &&
            (code [i] < 'A' || code [i] > 'F'))
            return (FALSE);

    return (TRUE);
}

const char *S9xProActionReplayToRaw (const char *code, uint32 &address, uint8 &byte)
{
    uint32 data = 0;
    if (strlen (code) != 8 || !S9xAllHex (code, 8) ||
        sscanf (code, "%x", &data) != 1)
	return ("Invalid Pro Action Replay code - should be 8 hex digits in length.");

    address = data >> 8;
    byte = (uint8) data;
    return (NULL);
}

const char *S9xGoldFingerToRaw (const char *code, uint32 &address, bool8 &sram,
			        uint8 &num_bytes, uint8 bytes[3])
{
    char tmp [15];
    if (strlen (code) != 14)
	return ("Invalid Gold Finger code should be 14 hex digits in length.");

    strncpy (tmp, code, 5);
    tmp [5] = 0;
    if (sscanf (tmp, "%x", &address) != 1)
	return ("Invalid Gold Finger code.");

    int i;
    for (i = 0; i < 3; i++)
    {
	strncpy (tmp, code + 5 + i * 2, 2);
	tmp [2] = 0;
	int byte;
	if (sscanf (tmp, "%x", &byte) != 1)
	    break;
	bytes [i] = (uint8) byte;
    }
    num_bytes = i;
    sram = code [13] == '1';
    return (NULL);
}

const char *S9xGameGenieToRaw (const char *code, uint32 &address, uint8 &byte)
{
    char new_code [12];
    
    if (strlen (code) != 9 || *(code + 4) != '-' || !S9xAllHex (code, 4) ||
        !S9xAllHex (code + 5, 4))
	return ("Invalid Game Genie(tm) code - should be 'xxxx-xxxx'.");

    strcpy (new_code, "0x");
    strncpy (new_code + 2, code, 4);
    strcpy (new_code + 6, code + 5);

    static char *real_hex  = "0123456789ABCDEF";
    static char *genie_hex = "DF4709156BC8A23E";
    
    for (int i = 2; i < 10; i++)
    {
	if (islower (new_code [i]))
	    new_code [i] = toupper (new_code [i]);
	int j;
	for (j = 0; j < 16; j++)
	{
	    if (new_code [i] == genie_hex [j])
	    {
		new_code [i] = real_hex [j];
		break;
	    }
	}
	if (j == 16)
	    return ("Invalid hex-character in Game Genie(tm) code");
    }
    uint32 data = 0;
    sscanf (new_code, "%x", &data);
    byte = (uint8)(data >> 24);
    address = data & 0xffffff;
    address = ((address & 0x003c00) << 10) +
	      ((address & 0x00003c) << 14) +
	      ((address & 0xf00000) >>  8) +
	      ((address & 0x000003) << 10) +
	      ((address & 0x00c000) >>  6) +
	      ((address & 0x0f0000) >> 12) +
	      ((address & 0x0003c0) >>  6);

    return (NULL);
}

void S9xStartCheatSearch (SCheatData *d)
{
    memmove (d->CWRAM, d->RAM, 0x20000);
    memmove (d->CSRAM, d->SRAM, 0x10000);
    memmove (d->CIRAM, &d->FillRAM [0x3000], 0x2000);
    memset ((char *) d->WRAM_BITS, 0xff, 0x20000 >> 3);
    memset ((char *) d->SRAM_BITS, 0xff, 0x10000 >> 3);
    memset ((char *) d->IRAM_BITS, 0xff, 0x2000 >> 3);
}

#define BIT_CLEAR(a,v) \
(a)[(v) >> 5] &= ~(1 << ((v) & 31))

#define BIT_SET(a,v) \
(a)[(v) >> 5] |= 1 << ((v) & 31)

#define TEST_BIT(a,v) \
((a)[(v) >> 5] & (1 << ((v) & 31)))

#define _C(c,a,b) \
((c) == S9X_LESS_THAN ? (a) < (b) : \
 (c) == S9X_GREATER_THAN ? (a) > (b) : \
 (c) == S9X_LESS_THAN_OR_EQUAL ? (a) <= (b) : \
 (c) == S9X_GREATER_THAN_OR_EQUAL ? (a) >= (b) : \
 (c) == S9X_EQUAL ? (a) == (b) : \
 (a) != (b))

#define _D(s,m,o) \
((s) == S9X_8_BITS ? (uint8) (*((m) + (o))) : \
 (s) == S9X_16_BITS ? ((uint16) (*((m) + (o)) + (*((m) + (o) + 1) << 8))) : \
 (s) == S9X_24_BITS ? ((uint32) (*((m) + (o)) + (*((m) + (o) + 1) << 8) + (*((m) + (o) + 2) << 16))) : \
((uint32)  (*((m) + (o)) + (*((m) + (o) + 1) << 8) + (*((m) + (o) + 2) << 16) + (*((m) + (o) + 3) << 24))))

#define _DS(s,m,o) \
((s) == S9X_8_BITS ? ((int8) *((m) + (o))) : \
 (s) == S9X_16_BITS ? ((int16) (*((m) + (o)) + (*((m) + (o) + 1) << 8))) : \
 (s) == S9X_24_BITS ? (((int32) ((*((m) + (o)) + (*((m) + (o) + 1) << 8) + (*((m) + (o) + 2) << 16)) << 8)) >> 8): \
 ((int32) (*((m) + (o)) + (*((m) + (o) + 1) << 8) + (*((m) + (o) + 2) << 16) + (*((m) + (o) + 3) << 24))))

void S9xSearchForChange (SCheatData *d, S9xCheatComparisonType cmp, 
                         S9xCheatDataSize size, bool8 is_signed, bool8 update)
{
    int l;

    switch (size)
    {
    case S9X_8_BITS: l = 0; break;
    case S9X_16_BITS: l = 1; break;
    case S9X_24_BITS: l = 2; break;
    default:
    case S9X_32_BITS: l = 3; break;
    }

    int i;
    if (is_signed)
    {
        for (i = 0; i < 0x20000 - l; i++)
        {
            if (TEST_BIT (d->WRAM_BITS, i) &&
                _C(cmp, _DS(size, d->RAM, i), _DS(size, d->CWRAM, i)))
            {
                if (update)
                    d->CWRAM [i] = d->RAM [i];
            }
            else
                BIT_CLEAR (d->WRAM_BITS, i);
        }
        
        for (i = 0; i < 0x10000 - l; i++)
        {
            if (TEST_BIT (d->SRAM_BITS, i) &&
                _C(cmp, _DS(size, d->SRAM, i), _DS(size, d->CSRAM, i)))
            {
                if (update)
                    d->CSRAM [i] = d->SRAM [i];
            }
            else
                BIT_CLEAR (d->SRAM_BITS, i);
        }
        
        for (i = 0; i < 0x2000 - l; i++)
        {
            if (TEST_BIT (d->IRAM_BITS, i) &&
                _C(cmp, _DS(size, d->FillRAM + 0x3000, i), _DS(size, d->CIRAM, i)))
            {
                if (update)
                    d->CIRAM [i] = d->FillRAM [i + 0x3000];
            }
            else
                BIT_CLEAR (d->IRAM_BITS, i);
        }
    }
    else
    {
        for (i = 0; i < 0x20000 - l; i++)
        {
            if (TEST_BIT (d->WRAM_BITS, i) &&
                _C(cmp, _D(size, d->RAM, i), _D(size, d->CWRAM, i)))
            {
                if (update)
                    d->CWRAM [i] = d->RAM [i];
            }
            else
                BIT_CLEAR (d->WRAM_BITS, i);
        }
        
        for (i = 0; i < 0x10000 - l; i++)
        {
            if (TEST_BIT (d->SRAM_BITS, i) &&
                _C(cmp, _D(size, d->SRAM, i), _D(size, d->CSRAM, i)))
            {
                if (update)
                    d->CSRAM [i] = d->SRAM [i];
            }
            else
                BIT_CLEAR (d->SRAM_BITS, i);
        }
        
        for (i = 0; i < 0x2000 - l; i++)
        {
            if (TEST_BIT (d->IRAM_BITS, i) &&
                _C(cmp, _D(size, d->FillRAM + 0x3000, i), _D(size, d->CIRAM, i)))
            {
                if (update)
                    d->CIRAM [i] = d->FillRAM [i + 0x3000];
            }
            else
                BIT_CLEAR (d->IRAM_BITS, i);
        }
    }
}

void S9xSearchForValue (SCheatData *d, S9xCheatComparisonType cmp, 
                        S9xCheatDataSize size, uint32 value, 
                        bool8 is_signed, bool8 update)
{
    int l;

    switch (size)
    {
    case S9X_8_BITS: l = 0; break;
    case S9X_16_BITS: l = 1; break;
    case S9X_24_BITS: l = 2; break;
    default:
    case S9X_32_BITS: l = 3; break;
    }

    int i;

    if (is_signed)
    {
        for (i = 0; i < 0x20000 - l; i++)
        {
            if (TEST_BIT (d->WRAM_BITS, i) &&
                _C(cmp, _DS(size, d->RAM, i), (int32) value))
            {
                if (update)
                    d->CWRAM [i] = d->RAM [i];
            }
            else
                BIT_CLEAR (d->WRAM_BITS, i);
        }
        
        for (i = 0; i < 0x10000 - l; i++)
        {
            if (TEST_BIT (d->SRAM_BITS, i) &&
                _C(cmp, _DS(size, d->SRAM, i), (int32) value))
            {
                if (update)
                    d->CSRAM [i] = d->SRAM [i];
            }
            else
                BIT_CLEAR (d->SRAM_BITS, i);
        }
        
        for (i = 0; i < 0x2000 - l; i++)
        {
            if (TEST_BIT (d->IRAM_BITS, i) &&
                _C(cmp, _DS(size, d->FillRAM + 0x3000, i), (int32) value))
            {
                if (update)
                    d->CIRAM [i] = d->FillRAM [i + 0x3000];
            }
            else
                BIT_CLEAR (d->IRAM_BITS, i);
        }
    }
    else
    {
        for (i = 0; i < 0x20000 - l; i++)
        {
            if (TEST_BIT (d->WRAM_BITS, i) &&
                _C(cmp, _D(size, d->RAM, i), value))
            {
                if (update)
                    d->CWRAM [i] = d->RAM [i];
            }
            else
                BIT_CLEAR (d->WRAM_BITS, i);
        }
        
        for (i = 0; i < 0x10000 - l; i++)
        {
            if (TEST_BIT (d->SRAM_BITS, i) &&
                _C(cmp, _D(size, d->SRAM, i), value))
            {
                if (update)
                    d->CSRAM [i] = d->SRAM [i];
            }
            else
                BIT_CLEAR (d->SRAM_BITS, i);
        }
        
        for (i = 0; i < 0x2000 - l; i++)
        {
            if (TEST_BIT (d->IRAM_BITS, i) &&
                _C(cmp, _D(size, d->FillRAM + 0x3000, i), value))
            {
                if (update)
                    d->CIRAM [i] = d->FillRAM [i + 0x3000];
            }
            else
                BIT_CLEAR (d->IRAM_BITS, i);
        }
    }
}

void S9xOutputCheatSearchResults (SCheatData *d)
{
    int i;
    for (i = 0; i < 0x20000; i++)
    {
	if (TEST_BIT (d->WRAM_BITS, i))
	    printf ("WRAM: %05x: %02x\n", i, d->RAM [i]);
    }

    for (i = 0; i < 0x10000; i++)
    {
	if (TEST_BIT (d->SRAM_BITS, i))
	    printf ("SRAM: %04x: %02x\n", i, d->SRAM [i]);
    }

    for (i = 0; i < 0x2000; i++)
    {
	if (TEST_BIT (d->IRAM_BITS, i))
	    printf ("IRAM: %05x: %02x\n", i, d->FillRAM [i + 0x3000]);
    }
}