mirror of https://github.com/bsnes-emu/bsnes.git
201 lines
7.8 KiB
C
201 lines
7.8 KiB
C
#include "gb.h"
|
|
|
|
/* TODO: Emulation is VERY basic and assumes the ROM correctly uses the printer's interface.
|
|
Incorrect usage is not correctly emulated, as it's not well documented, nor do I
|
|
have my own GB Printer to figure it out myself.
|
|
|
|
It also does not currently emulate communication timeout, which means that a bug
|
|
might prevent the printer operation until the GameBoy is restarted.
|
|
|
|
Also, field mask values are assumed. */
|
|
|
|
static void handle_command(GB_gameboy_t *gb)
|
|
{
|
|
|
|
switch (gb->printer.command_id) {
|
|
case GB_PRINTER_INIT_COMMAND:
|
|
gb->printer.status = 0;
|
|
gb->printer.image_offset = 0;
|
|
break;
|
|
|
|
case GB_PRINTER_START_COMMAND:
|
|
if (gb->printer.command_length == 4) {
|
|
gb->printer.status = 6; /* Printing */
|
|
uint32_t image[gb->printer.image_offset];
|
|
uint8_t palette = gb->printer.command_data[2];
|
|
uint32_t colors[4] = {gb->rgb_encode_callback(gb, 0xff, 0xff, 0xff),
|
|
gb->rgb_encode_callback(gb, 0xaa, 0xaa, 0xaa),
|
|
gb->rgb_encode_callback(gb, 0x55, 0x55, 0x55),
|
|
gb->rgb_encode_callback(gb, 0x00, 0x00, 0x00)};
|
|
for (unsigned i = 0; i < gb->printer.image_offset; i++) {
|
|
image[i] = colors[(palette >> (gb->printer.image[i] * 2)) & 3];
|
|
}
|
|
|
|
if (gb->printer.callback) {
|
|
gb->printer.callback(gb, image, gb->printer.image_offset / 160,
|
|
gb->printer.command_data[1] >> 4, gb->printer.command_data[1] & 7,
|
|
gb->printer.command_data[3] & 0x7F);
|
|
}
|
|
|
|
gb->printer.image_offset = 0;
|
|
}
|
|
break;
|
|
|
|
case GB_PRINTER_DATA_COMMAND:
|
|
if (gb->printer.command_length == GB_PRINTER_DATA_SIZE) {
|
|
gb->printer.image_offset %= sizeof(gb->printer.image);
|
|
gb->printer.status = 8; /* Received 0x280 bytes */
|
|
|
|
uint8_t *byte = gb->printer.command_data;
|
|
|
|
for (unsigned row = 2; row--; ) {
|
|
for (unsigned tile_x = 0; tile_x < 160 / 8; tile_x++) {
|
|
for (unsigned y = 0; y < 8; y++, byte += 2) {
|
|
for (unsigned x_pixel = 0; x_pixel < 8; x_pixel++) {
|
|
gb->printer.image[gb->printer.image_offset + tile_x * 8 + x_pixel + y * 160] =
|
|
((*byte) >> 7) | (((*(byte + 1)) >> 7) << 1);
|
|
(*byte) <<= 1;
|
|
(*(byte + 1)) <<= 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
gb->printer.image_offset += 8 * 160;
|
|
}
|
|
}
|
|
|
|
case GB_PRINTER_NOP_COMMAND:
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void serial_start(GB_gameboy_t *gb, uint8_t byte_received)
|
|
{
|
|
gb->printer.byte_to_send = 0;
|
|
switch (gb->printer.command_state) {
|
|
case GB_PRINTER_COMMAND_MAGIC1:
|
|
if (byte_received != 0x88) {
|
|
return;
|
|
}
|
|
gb->printer.status &= ~1;
|
|
gb->printer.command_length = 0;
|
|
gb->printer.checksum = 0;
|
|
break;
|
|
|
|
case GB_PRINTER_COMMAND_MAGIC2:
|
|
if (byte_received != 0x33) {
|
|
if (byte_received != 0x88) {
|
|
gb->printer.command_state = GB_PRINTER_COMMAND_MAGIC1;
|
|
}
|
|
return;
|
|
}
|
|
break;
|
|
|
|
case GB_PRINTER_COMMAND_ID:
|
|
gb->printer.command_id = byte_received & 0xF;
|
|
break;
|
|
|
|
case GB_PRINTER_COMMAND_COMPRESSION:
|
|
gb->printer.compression = byte_received & 1;
|
|
break;
|
|
|
|
case GB_PRINTER_COMMAND_LENGTH_LOW:
|
|
gb->printer.length_left = byte_received;
|
|
break;
|
|
|
|
case GB_PRINTER_COMMAND_LENGTH_HIGH:
|
|
gb->printer.length_left |= (byte_received & 3) << 8;
|
|
break;
|
|
|
|
case GB_PRINTER_COMMAND_DATA:
|
|
if (gb->printer.command_length != GB_PRINTER_MAX_COMMAND_LENGTH) {
|
|
if (gb->printer.compression) {
|
|
if (!gb->printer.compression_run_lenth) {
|
|
gb->printer.compression_run_is_compressed = byte_received & 0x80;
|
|
gb->printer.compression_run_lenth = (byte_received & 0x7F) + 1 + gb->printer.compression_run_is_compressed;
|
|
}
|
|
else if (gb->printer.compression_run_is_compressed) {
|
|
while (gb->printer.compression_run_lenth) {
|
|
gb->printer.command_data[gb->printer.command_length++] = byte_received;
|
|
gb->printer.compression_run_lenth--;
|
|
if (gb->printer.command_length == GB_PRINTER_MAX_COMMAND_LENGTH) {
|
|
gb->printer.compression_run_lenth = 0;
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
gb->printer.command_data[gb->printer.command_length++] = byte_received;
|
|
gb->printer.compression_run_lenth--;
|
|
}
|
|
}
|
|
else {
|
|
gb->printer.command_data[gb->printer.command_length++] = byte_received;
|
|
}
|
|
}
|
|
gb->printer.length_left--;
|
|
break;
|
|
|
|
case GB_PRINTER_COMMAND_CHECKSUM_LOW:
|
|
gb->printer.checksum ^= byte_received;
|
|
break;
|
|
|
|
case GB_PRINTER_COMMAND_CHECKSUM_HIGH:
|
|
gb->printer.checksum ^= byte_received << 8;
|
|
if (gb->printer.checksum) {
|
|
gb->printer.status |= 1; /* Checksum error*/
|
|
gb->printer.command_state = GB_PRINTER_COMMAND_MAGIC1;
|
|
return;
|
|
}
|
|
break;
|
|
case GB_PRINTER_COMMAND_ACTIVE:
|
|
gb->printer.byte_to_send = 0x81;
|
|
break;
|
|
case GB_PRINTER_COMMAND_STATUS:
|
|
|
|
if ((gb->printer.command_id & 0xF) == GB_PRINTER_INIT_COMMAND) {
|
|
/* Games expect INIT commands to return 0? */
|
|
gb->printer.byte_to_send = 0;
|
|
}
|
|
else {
|
|
gb->printer.byte_to_send = gb->printer.status;
|
|
}
|
|
|
|
/* Printing is done instantly, but let the game recieve a 6 (Printing) status at least once, for compatibility */
|
|
if (gb->printer.status == 6) {
|
|
gb->printer.status = 4; /* Done */
|
|
}
|
|
|
|
gb->printer.command_state = GB_PRINTER_COMMAND_MAGIC1;
|
|
handle_command(gb);
|
|
return;
|
|
}
|
|
|
|
if (gb->printer.command_state >= GB_PRINTER_COMMAND_ID && gb->printer.command_state < GB_PRINTER_COMMAND_CHECKSUM_LOW) {
|
|
gb->printer.checksum += byte_received;
|
|
}
|
|
|
|
if (gb->printer.command_state != GB_PRINTER_COMMAND_DATA) {
|
|
gb->printer.command_state++;
|
|
}
|
|
|
|
if (gb->printer.command_state == GB_PRINTER_COMMAND_DATA) {
|
|
if (gb->printer.length_left == 0) {
|
|
gb->printer.command_state++;
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
static uint8_t serial_end(GB_gameboy_t *gb)
|
|
{
|
|
return gb->printer.byte_to_send;
|
|
}
|
|
|
|
void GB_connect_printer(GB_gameboy_t *gb, GB_print_image_callback_t callback)
|
|
{
|
|
memset(&gb->printer, 0, sizeof(gb->printer));
|
|
GB_set_serial_transfer_start_callback(gb, serial_start);
|
|
GB_set_serial_transfer_end_callback(gb, serial_end);
|
|
gb->printer.callback = callback;
|
|
} |