grip.cpp

SFC游戏模拟器 snes9x 1.43 的原代码

/*******************************************************************************
  Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 
  (c) Copyright 1996 - 2002 Gary Henderson ([e-mail]) and
                            Jerremy Koot ([e-mail])

  (c) Copyright 2001 - 2004 John Weidman ([e-mail])

  (c) Copyright 2002 - 2004 Brad Jorsch ([e-mail]),
                            funkyass ([e-mail]),
                            Joel Yliluoma (http://iki.fi/bisqwit/)
                            Kris Bleakley ([e-mail]),
                            Matthew Kendora,
                            Nach ([e-mail]),
                            Peter Bortas ([e-mail]) and
                            zones ([e-mail])

  C4 x86 assembler and some C emulation code
  (c) Copyright 2000 - 2003 zsKnight ([e-mail]),
                            _Demo_ ([e-mail]), and Nach

  C4 C++ code
  (c) Copyright 2003 Brad Jorsch

  DSP-1 emulator code
  (c) Copyright 1998 - 2004 Ivar ([e-mail]), _Demo_, Gary Henderson,
                            John Weidman, neviksti ([e-mail]),
                            Kris Bleakley, Andreas Naive

  DSP-2 emulator code
  (c) Copyright 2003 Kris Bleakley, John Weidman, neviksti, Matthew Kendora, and
                     Lord Nightmare ([e-mail]

  OBC1 emulator code
  (c) Copyright 2001 - 2004 zsKnight, pagefault ([e-mail]) and
                            Kris Bleakley
  Ported from x86 assembler to C by sanmaiwashi

  SPC7110 and RTC C++ emulator code
  (c) Copyright 2002 Matthew Kendora with research by
                     zsKnight, John Weidman, and Dark Force

  S-DD1 C emulator code
  (c) Copyright 2003 Brad Jorsch with research by
                     Andreas Naive and John Weidman
 
  S-RTC C emulator code
  (c) Copyright 2001 John Weidman
  
  ST010 C++ emulator code
  (c) Copyright 2003 Feather, Kris Bleakley, John Weidman and Matthew Kendora

  Super FX x86 assembler emulator code 
  (c) Copyright 1998 - 2003 zsKnight, _Demo_, and pagefault 

  Super FX C emulator code 
  (c) Copyright 1997 - 1999 Ivar, Gary Henderson and John Weidman


  SH assembler code partly based on x86 assembler code
  (c) Copyright 2002 - 2004 Marcus Comstedt ([e-mail]) 

 
  Specific ports contains the works of other authors. See headers in
  individual files.
 
  Snes9x homepage: http://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.
*******************************************************************************/
/************************************************************************\
**                                                                      **
**                GrIP Prototype API Interface Library                  **
**                                for                                   **
**                               DJGPP                                  **
**                                                                      **
**                           Revision 1.00                              **
**                                                                      **
**  COPYRIGHT:                                                          **
**                                                                      **
**    (C) Copyright Advanced Gravis Computer Technology Ltd 1995.       **
**        All Rights Reserved.                                          **
**                                                                      **
**  DISCLAIMER OF WARRANTIES:                                           **
**                                                                      **
**    The following [enclosed] code is provided to you "AS IS",         **
**    without warranty of any kind.  You have a royalty-free right to   **
**    use, modify, reproduce and distribute the following code (and/or  **
**    any modified version) provided that you agree that Advanced       **
**    Gravis has no warranty obligations and shall not be liable for    **
**    any damages arising out of your use of this code, even if they    **
**    have been advised of the possibility of such damages.  This       **
**    Copyright statement and Disclaimer of Warranties may not be       **
**    removed.                                                          **
**                                                                      **
**  HISTORY:                                                            **
**                                                                      **
**    0.102   Jul 12 95   David Bollo     Initial public release on     **
**                                          GrIP hardware               **
**    0.200   Aug 10 95   David Bollo     Added Gravis Loadable Library **
**                                          support                     **
**    0.201   Aug 11 95   David Bollo     Removed Borland C++ support   **
**                                          for maintenance reasons     **
**    1.00    Nov  1 95   David Bollo     First official release as     **
**                                          part of GrIP SDK            **
**                                                                      **
\************************************************************************/
#include <stdlib.h>
#include <go32.h>
#include <dpmi.h>
#include <sys/movedata.h>
#include <sys/farptr.h>
#include "grip.h"

/* Standard String Constants for Loadable Library */
char GrLibName[] = "GRIP.GLL";
char GrLibEnv[] = "GRIP";
char GrLibDir[] = "C:\\GRIP\\";

/* Global Thunking Data */
GRIP_THUNK GRIP_Thunk;
static int GRIP_Thunked = 0;
static unsigned int GRIP_CS;
static unsigned int GRIP_DS;
#if defined(GRIP_DEBUG)
static unsigned short GRIP_ES;
#endif

#ifdef __cplusplus
extern "C"
  {
#endif

#define DPMI_AllocDOS(a, b) (__dpmi_allocate_dos_memory(a, (int *) b) << 4)
#define DPMI_FreeDOS(a) __dpmi_free_dos_memory(a)
#define DPMI_AllocSel() __dpmi_allocate_ldt_descriptors(1)
#define DPMI_FreeSel(a) __dpmi_free_ldt_descriptor(a)

unsigned char DPMI_SetCodeAR(unsigned short sel);
unsigned char DPMI_SetDataAR(unsigned short sel);

unsigned char DPMI_SetBounds(unsigned short sel, unsigned long base, unsigned short lm) {
  if (__dpmi_set_segment_base_address(sel, base) == -1)  return -1;
  if (__dpmi_set_segment_limit(sel, lm - 1) == -1) return -1;
  return 0;
}

GRIP_bool8 GrLink(GRIP_BUF image, GRIP_VALUE size)
  {
  unsigned short img_off;     /* Offset of binary image     */
  unsigned short img_size;    /* Size of binary image       */
  unsigned char img_check;    /* Checksum of binary image   */
  unsigned long memory;       /* Image memory               */
  GRIP_BUF_C header;          /* Image header               */
  GRIP_BUF_C core;            /* Image core                 */
  int i;

  /* Check for duplicate GrLink calls */
  if (GRIP_Thunked) return 0;

  /* Sanity check the inputs */
  if (image == 0 || size < 16) return 0;

  /* Check the image header for the proper signature bytes */
  header = (GRIP_BUF_C) image;
  if (header[0] != 'D' || header[1] != 'B') return 0;

  /* Extract the image offsets from the header */
  img_off = ( (header[2] & 0x0F) << 12 ) |
            ( (header[3] & 0x0F) <<  8 ) |
            ( (header[4] & 0x0F) <<  4 ) |
            ( (header[5] & 0x0F) );
  img_size = ( (header[6] & 0x0F) << 12 ) |
             ( (header[7] & 0x0F) <<  8 ) |
             ( (header[8] & 0x0F) <<  4 ) |
             ( (header[9] & 0x0F) );
  img_check = ( (header[10] & 0x0F) <<  4 ) |
              ( (header[11] & 0x0F) );

  /* Compute the start of image core */
  if ( size < ((img_off + img_size) << 4) ) return 0;
  core = header + (img_off << 4);

  /* Verify the checksum */
  for (i = 0; i < (img_size << 4); i++) img_check ^= core[i];
  if (img_check != 0) return 0;

  /* Allocate memory for the core */
  memory = (unsigned long) DPMI_AllocDOS(img_size, &GRIP_DS);
  if (!memory) return 0;

  /* Copy the image */
  _dosmemputl(core, img_size << 2, memory);

  /* Allocate a code selector for the core */
  GRIP_CS = DPMI_AllocSel();
  if (GRIP_CS == 0) {
     DPMI_FreeDOS(GRIP_DS);
     return 0;
  }
  if (DPMI_SetBounds(GRIP_CS, memory, img_size << 4) != 0) {
     DPMI_FreeSel(GRIP_CS);
     DPMI_FreeDOS(GRIP_DS);
     return 0;
  }
  if (DPMI_SetCodeAR(GRIP_CS) != 0) {
     DPMI_FreeSel(GRIP_CS);
     DPMI_FreeDOS(GRIP_DS);
     return 0;
  }

  /* Prepare the thunking layer */
  for (i = 0; i < sizeof(GRIP_THUNK); i++)
    GRIP_Thunk[i] = ((GRIP_BUF_C)core)[i];

    *(GRIP_BUF_S)(GRIP_Thunk+0x02) = 0;
    *(GRIP_BUF_S)(GRIP_Thunk+0x06) = GRIP_CS;
    *(GRIP_BUF_S)(GRIP_Thunk+0x0C) = GRIP_CS;

  /* Allocate a debugging selector if GRIP_DEBUG is defined */
  #if defined(GRIP_DEBUG)
      /* I don't know what this does... at least it compiles okay */
      GRIP_ES = DPMI_AllocSel();
      if (GRIP_ES == 0) {
         DPMI_FreeSel(GRIP_CS);
         DPMI_FreeDOS(GRIP_DS);
         return 0;
      }
      if (DPMI_SetBounds(GRIP_ES, 0xB0000, 80*25*2) != 0)
        {
        DPMI_FreeSel(GRIP_ES);
        DPMI_FreeSel(GRIP_CS);
        DPMI_FreeDOS(GRIP_DS);
        return 0;
        }
      if (DPMI_SetDataAR(GRIP_ES) != 0)
        {
        DPMI_FreeSel(GRIP_ES);
        DPMI_FreeSel(GRIP_CS);
        DPMI_FreeDOS(GRIP_DS);
        return 0;
        }
      _farpokew(_dos_ds, memory + 0x12, 0xB000);
      _farpokew(_dos_ds, memory + 0x16, GRIP_ES);
  #else
    _farpokew(_dos_ds, memory + 0x12, 0);
    _farpokew(_dos_ds, memory + 0x16, 0);
  #endif

  // Save the data selector
  _farpokew(_dos_ds, memory + 0x10, 0);
  _farpokew(_dos_ds, memory + 0x14, GRIP_DS);

  /* Complete the link */
  if (Gr__Link() == 0)
    {
      #if defined(GRIP_DEBUG)
        DPMI_FreeSel(GRIP_ES);
      #endif
      DPMI_FreeSel(GRIP_CS);
      DPMI_FreeDOS(GRIP_DS);
    return 0;
    }

  GRIP_Thunked = 1;

  return 1;
  }

GRIP_bool8 GrUnlink(void)
  {
  // Check that the library has been loaded
  if (!GRIP_Thunked)
    return 0;

  // Unlink the library
  Gr__Unlink();

  // Free the library memory
    #if defined(GRIP_DEBUG)
      if (DPMI_FreeSel(GRIP_ES) != 0)
        return 0;
    #endif
    if (DPMI_FreeSel(GRIP_CS) != 0)
      return 0;
    if (DPMI_FreeDOS(GRIP_DS) != 0)
      return 0;

  GRIP_Thunked = 0;

  return 1;
  }

#ifdef __cplusplus
  }
#endif