vbagx/source/vba/dmg/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 "../agb/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;
}