vbagx/source/vba/gb/gbPrinter.cpp

// VisualBoyAdvance - Nintendo Gameboy/GameboyAdvance (TM) emulator.
// Copyright (C) 1999-2003 Forgotten
// Copyright (C) 2004 Forgotten and the VBA development team

// 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 <stdio.h>
#include <string.h>
#include "../GBA.h"

u8 gbPrinterStatus = 0;
int gbPrinterState = 0;
u8 gbPrinterData[0x280*9];
u8 gbPrinterPacket[0x400];
int gbPrinterCount = 0;
int gbPrinterDataCount = 0;
int gbPrinterDataSize = 0;
int gbPrinterResult = 0;

bool gbPrinterCheckCRC()
{
  u16 crc = 0;

  for(int i = 2; i < (6+gbPrinterDataSize); i++)
    {
      crc += gbPrinterPacket[i];
    }

  int msgCrc = gbPrinterPacket[6+gbPrinterDataSize] +
               (gbPrinterPacket[7+gbPrinterDataSize]<<8);

  return msgCrc == crc;
}

void gbPrinterReset()
{
  gbPrinterState = 0;
  gbPrinterDataSize = 0;
  gbPrinterDataCount = 0;
  gbPrinterCount = 0;
  gbPrinterStatus = 0;
  gbPrinterResult = 0;
}

void gbPrinterShowData()
{
  systemGbPrint(gbPrinterData,
                gbPrinterPacket[6],
                gbPrinterPacket[7],
                gbPrinterPacket[8],
                gbPrinterPacket[9]);
  /*
  allegro_init();
  install_keyboard();
  set_gfx_mode(GFX_AUTODETECT, 160, 144, 0, 0);
  PALETTE pal;
  pal[0].r = 255;
  pal[0].g = 255;
  pal[0].b = 255;
  pal[1].r = 168;
  pal[1].g = 168;
  pal[1].b = 168;
  pal[2].r = 96;
  pal[2].g = 96;
  pal[2].b = 96;
  pal[3].r = 0;
  pal[3].g = 0;
  pal[3].b = 0;
  set_palette(pal);
  acquire_screen();  
  u8 *data = gbPrinterData;
  for(int y = 0; y < 0x12; y++) {
    for(int x = 0; x < 0x14; x++) {
      for(int k = 0; k < 8; k++) {
        int a = *data++;
        int b = *data++;
        for(int j = 0; j < 8; j++) {
          int mask = 1 << (7-j);
          int c = 0;
          if(a & mask)
            c++;
          if(b & mask)
            c+=2;
          putpixel(screen, x*8+j, y*8+k, c);
        }
      }
    }
  }
  release_screen();
  while(!keypressed()) {
  }
  */
}

void gbPrinterReceiveData()
{
  if(gbPrinterPacket[3])
    { // compressed
      u8 *data = &gbPrinterPacket[6];
      u8 *dest = &gbPrinterData[gbPrinterDataCount];
      int len = 0;
      while(len < gbPrinterDataSize)
        {
          u8 control = *data++;
          if(control & 0x80)
            { // repeated data
              control &= 0x7f;
              control += 2;
              memset(dest, *data++, control);
              len += control;
              dest += control;
            }
          else
            { // raw data
              control++;
              memcpy(dest, data, control);
              dest += control;
              data += control;
              len += control;
            }
        }
    }
  else
    {
      memcpy(&gbPrinterData[gbPrinterDataCount],
             &gbPrinterPacket[6],
             gbPrinterDataSize);
      gbPrinterDataCount += gbPrinterDataSize;
    }
}

void gbPrinterCommand()
{
  switch(gbPrinterPacket[2])
    {
    case 0x01:
      // reset/initialize packet
      gbPrinterDataCount = 0;
      gbPrinterStatus = 0;
      break;
    case 0x02:
      // print packet
      gbPrinterShowData();
      break;
    case 0x04:
      // data packet
      gbPrinterReceiveData();
      break;
    case 0x0f:
      // NUL packet
      break;
    }
}

u8 gbPrinterSend(u8 b)
{
  switch(gbPrinterState)
    {
    case 0:
      gbPrinterCount = 0;
      // receiving preamble
      if(b == 0x88)
        {
          gbPrinterPacket[gbPrinterCount++] = b;
          gbPrinterState++;
        }
      else
        {
          // todo: handle failure
          gbPrinterReset();
        }
      break;
    case 1:
      // receiving preamble
      if(b == 0x33)
        {
          gbPrinterPacket[gbPrinterCount++] = b;
          gbPrinterState++;
        }
      else
        {
          // todo: handle failure
          gbPrinterReset();
        }
      break;
    case 2:
      // receiving header
      gbPrinterPacket[gbPrinterCount++] = b;
      if(gbPrinterCount == 6)
        {
          gbPrinterState++;
          gbPrinterDataSize = gbPrinterPacket[4] + (gbPrinterPacket[5]<<8);
        }
      break;
    case 3:
      // receiving data
      if(gbPrinterDataSize)
        {
          gbPrinterPacket[gbPrinterCount++] = b;
          if(gbPrinterCount == (6+gbPrinterDataSize))
            {
              gbPrinterState++;
            }
          break;
        }
      gbPrinterState++;
      // intentionally move to next if no data to receive
    case 4:
      // receiving CRC
      gbPrinterPacket[gbPrinterCount++] = b;
      gbPrinterState++;
      break;
    case 5:
      // receiving CRC-2
      gbPrinterPacket[gbPrinterCount++] = b;
      if(gbPrinterCheckCRC())
        {
          gbPrinterCommand();
        }
      gbPrinterState++;
      break;
    case 6:
      // receiving dummy 1
      gbPrinterPacket[gbPrinterCount++] = b;
      gbPrinterResult = 0x81;
      gbPrinterState++;
      break;
    case 7:
      // receiving dummy 2
      gbPrinterPacket[gbPrinterCount++] = b;
      gbPrinterResult = gbPrinterStatus;
      gbPrinterState = 0;
      gbPrinterCount = 0;
      break;
    }
  return gbPrinterResult;
}