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Support for multi-packet SGB commands

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This commit is contained in:
Lior Halphon 2018-11-13 23:45:26 +02:00
parent 7735d638c6
commit 6ba5cfbeef
2 changed files with 51 additions and 18 deletions
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5
Core/gb.h
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@ -469,10 +469,11 @@ struct GB_gameboy_internal_s {
/* Super Game Boy state, only dumped/loaded for relevant models */
GB_SECTION(sgb,
uint8_t sgb_command[16];
uint8_t sgb_command_write_index;
uint8_t sgb_command[16 * 7];
uint16_t sgb_command_write_index;
bool sgb_ready_for_pulse;
bool sgb_ready_for_write;
bool sgb_ready_for_stop;
bool sgb_disable_commands;
/* Multiplayer Input */
uint8_t sgb_player_count, sgb_current_player;

44
Core/sgb.c
View File

@ -4,6 +4,8 @@ enum {
MLT_REQ = 0x11,
};
#define SGB_PACKET_SIZE 16
static void command_ready(GB_gameboy_t *gb)
{
/* SGB header commands are used to send the contents of the header to the SNES CPU.
@ -12,7 +14,8 @@ static void command_ready(GB_gameboy_t *gb)
Checksum: Simple one byte sum for the following content bytes
0xE content bytes. The last command, FB, is padded with zeros, so information past the header is not sent. */
if (gb->sgb_command[0] >= 0xF0) {
if ((gb->sgb_command[0] & 0xF1) == 0xF1) {
uint8_t checksum = 0;
for (unsigned i = 2; i < 0x10; i++) {
checksum += gb->sgb_command[i];
@ -22,7 +25,6 @@ static void command_ready(GB_gameboy_t *gb)
gb->sgb_disable_commands = true;
return;
}
}
if (gb->sgb_command[0] == 0xf9) {
if (gb->sgb_command[0xc] != 3) { // SGB Flag
GB_log(gb, "SGB flag is not 0x03, disabling SGB features\n");
@ -35,12 +37,23 @@ static void command_ready(GB_gameboy_t *gb)
gb->sgb_disable_commands = true;
}
}
return;
}
switch (gb->sgb_command[0] >> 3) {
case MLT_REQ:
gb->sgb_player_count = (uint8_t[]){1, 2, 1, 4}[gb->sgb_command[1] & 3];
gb->sgb_current_player = gb->sgb_player_count - 1;
break;
default:
GB_log(gb, "Unimplemented SGB command %x: ", gb->sgb_command[0] >> 3);
for (unsigned i = 0; i < gb->sgb_command_write_index / 8; i++) {
GB_log(gb, "%02x ", gb->sgb_command[i]);
}
GB_log(gb, "\n");
;
}
}
@ -48,6 +61,12 @@ void GB_sgb_write(GB_gameboy_t *gb, uint8_t value)
{
if (!GB_is_sgb(gb)) return;
if (gb->sgb_disable_commands) return;
if (gb->sgb_command_write_index >= sizeof(gb->sgb_command) * 8) return;
uint16_t command_size = (gb->sgb_command[0] & 7 ?: 1) * SGB_PACKET_SIZE * 8;
if ((gb->sgb_command[0] & 0xF1) == 0xF1) {
command_size = SGB_PACKET_SIZE * 8;
}
switch ((value >> 4) & 3) {
case 3:
@ -56,35 +75,48 @@ void GB_sgb_write(GB_gameboy_t *gb, uint8_t value)
case 2: // Zero
if (!gb->sgb_ready_for_pulse || !gb->sgb_ready_for_write) return;
if (gb->sgb_command_write_index >= sizeof(gb->sgb_command) * 8) {
if (gb->sgb_ready_for_stop) {
if (gb->sgb_command_write_index == command_size) {
command_ready(gb);
gb->sgb_command_write_index = 0;
memset(gb->sgb_command, 0, sizeof(gb->sgb_command));
}
gb->sgb_ready_for_pulse = false;
gb->sgb_ready_for_write = false;
gb->sgb_ready_for_stop = false;
}
else {
gb->sgb_command_write_index++;
gb->sgb_ready_for_pulse = false;
if (((gb->sgb_command_write_index) & (SGB_PACKET_SIZE * 8 - 1)) == 0) {
gb->sgb_ready_for_stop = true;
}
}
break;
case 1: // One
if (!gb->sgb_ready_for_pulse || !gb->sgb_ready_for_write) return;
if (gb->sgb_command_write_index >= sizeof(gb->sgb_command) * 8) {
if (gb->sgb_ready_for_stop) {
GB_log(gb, "Corrupt SGB command.\n");
gb->sgb_ready_for_pulse = false;
gb->sgb_ready_for_write = false;
gb->sgb_command_write_index = 0;
memset(gb->sgb_command, 0, sizeof(gb->sgb_command));
}
else {
gb->sgb_command[gb->sgb_command_write_index / 8] |= 1 << (gb->sgb_command_write_index & 7);
gb->sgb_command_write_index++;
gb->sgb_ready_for_pulse = false;
if (((gb->sgb_command_write_index) & (SGB_PACKET_SIZE * 8 - 1)) == 0) {
gb->sgb_ready_for_stop = true;
}
}
break;
case 0:
if (!gb->sgb_ready_for_pulse) return;
gb->sgb_ready_for_pulse = false;
gb->sgb_ready_for_write = true;
gb->sgb_command_write_index = 0;
memset(gb->sgb_command, 0, sizeof(gb->sgb_command));
gb->sgb_ready_for_pulse = false;
if (gb->sgb_player_count > 1 && (value & 0x30) != (gb->io_registers[GB_IO_JOYP] & 0x30)) {
gb->sgb_current_player++;
gb->sgb_current_player &= gb->sgb_player_count - 1;