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Merge pull request #17 from mpostaire/dev
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Dev
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@mpostaire
mpostaire committed Oct 4, 2023
2 parents 8ccc389 + ae50567 commit 5ac2aef
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Showing 23 changed files with 325 additions and 356 deletions.
2 changes: 0 additions & 2 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -83,8 +83,6 @@ There is also support for gamepad controllers.
### TODO

- implement other MBCs
- implement printer
- implement GBC and HuC1 IR
- find out what are the accurate timings for the ppu pixel fifo/fetcher (especially for corner cases)
- better audio/video sync
- android link cable via bluetooth + cross platform link cable
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150 changes: 75 additions & 75 deletions src/core/gb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -82,12 +82,16 @@ int gb_step(gb_t *gb) {
return gb_step_linked(gb, 1);
}

gb_t *gb_init(const byte_t *rom_data, size_t rom_size, gb_options_t *opts) {
int gb_is_rom_valid(const byte_t *rom) {
return parse_header_mbc_byte(rom[0x0147], NULL, NULL, NULL, NULL, NULL) && validate_header_checksum(rom);
}

gb_t *gb_init(const byte_t *rom, size_t rom_size, gb_options_t *opts) {
gb_t *gb = xcalloc(1, sizeof(gb_t));
gb->exit_on_invalid_opcode = 1;
gb_set_options(gb, opts);

if (!mmu_init(gb, rom_data, rom_size)) {
if (!mmu_init(gb, rom, rom_size)) {
free(gb);
return NULL;
}
Expand All @@ -114,8 +118,8 @@ void gb_quit(gb_t *gb) {

void gb_reset(gb_t *gb, gb_mode_t mode) {
size_t rom_size = gb->mmu->rom_size;
byte_t *rom_data = xmalloc(rom_size);
memcpy(rom_data, gb->mmu->rom, rom_size);
byte_t *rom = xmalloc(rom_size);
memcpy(rom, gb->mmu->rom, rom_size);

gb->mode = 0;
gb_options_t opts;
Expand All @@ -134,7 +138,7 @@ void gb_reset(gb_t *gb, gb_mode_t mode) {
link_quit(gb);
joypad_quit(gb);

mmu_init(gb, rom_data, rom_size);
mmu_init(gb, rom, rom_size);
cpu_init(gb);
apu_init(gb);
ppu_init(gb);
Expand All @@ -145,7 +149,7 @@ void gb_reset(gb_t *gb, gb_mode_t mode) {
if (save_data)
gb_load_save(gb, save_data, save_len);

free(rom_data);
free(rom);
}

static const char *get_new_licensee(gb_t *gb) {
Expand Down Expand Up @@ -492,15 +496,8 @@ byte_t *gb_get_save(gb_t *gb, size_t *save_length) {
return NULL;
}

size_t rtc_timestamp_len = 0;
size_t rtc_len = 0;
char *rtc_timestamp = NULL;
if (gb->mmu->has_rtc) {
rtc_timestamp = time_to_string(time(NULL), &rtc_timestamp_len);
rtc_len = 10 + rtc_timestamp_len;
}

size_t eram_len = 0x2000 * gb->mmu->eram_banks;
size_t rtc_len = gb->mmu->has_rtc ? 48 : 0;
size_t eram_len = gb->mmu->eram_banks * ERAM_BANK_SIZE;
size_t total_len = eram_len + rtc_len;
if (save_length)
*save_length = total_len;
Expand All @@ -513,20 +510,25 @@ byte_t *gb_get_save(gb_t *gb, size_t *save_length) {
if (eram_len > 0)
memcpy(save_data, gb->mmu->eram, eram_len);

if (rtc_timestamp) {
memcpy(&save_data[eram_len], &gb->mmu->mbc.mbc3.rtc.s, 1);
memcpy(&save_data[eram_len + 1], &gb->mmu->mbc.mbc3.rtc.m, 1);
memcpy(&save_data[eram_len + 2], &gb->mmu->mbc.mbc3.rtc.h, 1);
memcpy(&save_data[eram_len + 3], &gb->mmu->mbc.mbc3.rtc.dl, 1);
memcpy(&save_data[eram_len + 4], &gb->mmu->mbc.mbc3.rtc.dh, 1);
memcpy(&save_data[eram_len + 5], &gb->mmu->mbc.mbc3.rtc.latched_s, 1);
memcpy(&save_data[eram_len + 6], &gb->mmu->mbc.mbc3.rtc.latched_m, 1);
memcpy(&save_data[eram_len + 7], &gb->mmu->mbc.mbc3.rtc.latched_h, 1);
memcpy(&save_data[eram_len + 8], &gb->mmu->mbc.mbc3.rtc.latched_dl, 1);
memcpy(&save_data[eram_len + 9], &gb->mmu->mbc.mbc3.rtc.latched_dh, 1);

memcpy(&save_data[eram_len + 10], rtc_timestamp, rtc_timestamp_len);
free(rtc_timestamp);
if (rtc_len > 0) {
save_data[eram_len] = gb->mmu->mbc.mbc3.rtc.s;
save_data[eram_len + 4] = gb->mmu->mbc.mbc3.rtc.m;
save_data[eram_len + 8] = gb->mmu->mbc.mbc3.rtc.h;
save_data[eram_len + 12] = gb->mmu->mbc.mbc3.rtc.dl;
save_data[eram_len + 16] = gb->mmu->mbc.mbc3.rtc.dh;
save_data[eram_len + 20] = gb->mmu->mbc.mbc3.rtc.latched_s;
save_data[eram_len + 24] = gb->mmu->mbc.mbc3.rtc.latched_m;
save_data[eram_len + 28] = gb->mmu->mbc.mbc3.rtc.latched_h;
save_data[eram_len + 32] = gb->mmu->mbc.mbc3.rtc.latched_dl;
save_data[eram_len + 36] = gb->mmu->mbc.mbc3.rtc.latched_dh;
// fill rtc save padding bytes with 0
for (size_t i = eram_len; i < eram_len + 40; i++)
if (i % 4 != 0)
save_data[i] = 0;

time_t rtc_timestamp = time(NULL);
for (int i = 0; i < 8; i++) // little endian serialization of rtc_timestamp
save_data[eram_len + 40 + i] = rtc_timestamp >> (i * 8);
}

return save_data;
Expand All @@ -544,61 +546,59 @@ int gb_load_save(gb_t *gb, byte_t *save_data, size_t save_length) {
if (!gb->mmu->has_battery || (!gb->mmu->has_rtc && gb->mmu->eram_banks == 0))
return 0;

size_t eram_len = gb->mmu->eram_banks * VRAM_BANK_SIZE;

size_t rtc_len = 0;
if (gb->mmu->has_rtc) {
size_t rtc_timestamp_len = strlen((char *) &save_data[eram_len + 10]) + 1;
rtc_len = 10 + rtc_timestamp_len;
}

size_t total_len = eram_len + rtc_len;
if (total_len != save_length || total_len == 0)
size_t eram_len = gb->mmu->eram_banks * ERAM_BANK_SIZE;
if (save_length < eram_len || save_length == 0)
return 0;

if (eram_len > 0)
memcpy(gb->mmu->eram, save_data, eram_len);

if (rtc_len > 0) {
// get saved rtc registers and timestamp
byte_t s = save_data[eram_len];
byte_t m = save_data[eram_len + 1];
byte_t h = save_data[eram_len + 2];
byte_t dl = save_data[eram_len + 3];
byte_t dh = save_data[eram_len + 4];
gb->mmu->mbc.mbc3.rtc.latched_s = save_data[eram_len + 5];
gb->mmu->mbc.mbc3.rtc.latched_m = save_data[eram_len + 6];
gb->mmu->mbc.mbc3.rtc.latched_h = save_data[eram_len + 7];
gb->mmu->mbc.mbc3.rtc.latched_dl = save_data[eram_len + 8];
gb->mmu->mbc.mbc3.rtc.latched_dh = save_data[eram_len + 9];

time_t rtc_timestamp = string_to_time((char *) &save_data[eram_len + 10]);

// add elapsed time
time_t rtc_registers_time = s + m * 60 + h * 3600 + ((dh << 8) | dl) * 86400;
rtc_registers_time += time(NULL) - rtc_timestamp;

// convert elapsed time back into rtc registers
word_t d = rtc_registers_time / 86400;
rtc_registers_time %= 86400;

// day overflow
if (d >= 0x0200) {
SET_BIT(gb->mmu->mbc.mbc3.rtc.dh, 7);
d %= 0x0200;
}
size_t rtc_len = gb->mmu->has_rtc ? save_length - eram_len : 0;
if (rtc_len != 44 && rtc_len != 48) {
eprintf("Invalid rtc format\n");
return 1;
}

// get saved rtc registers and timestamp
byte_t s = save_data[eram_len];
byte_t m = save_data[eram_len + 4];
byte_t h = save_data[eram_len + 8];
byte_t dl = save_data[eram_len + 12];
byte_t dh = save_data[eram_len + 16];
gb->mmu->mbc.mbc3.rtc.latched_s = save_data[eram_len + 20];
gb->mmu->mbc.mbc3.rtc.latched_m = save_data[eram_len + 24];
gb->mmu->mbc.mbc3.rtc.latched_h = save_data[eram_len + 28];
gb->mmu->mbc.mbc3.rtc.latched_dl = save_data[eram_len + 32];
gb->mmu->mbc.mbc3.rtc.latched_dh = save_data[eram_len + 36];

time_t rtc_timestamp = 0;
for (int i = 0; i < (rtc_len == 48 ? 8 : 4); i++) // little endian unserialization of rtc_timestamp
rtc_timestamp |= ((time_t) save_data[eram_len + 40 + i]) << (i * 8);

// add elapsed time
time_t rtc_registers_time = s + m * 60 + h * 3600 + ((dh << 8) | dl) * 86400;
rtc_registers_time += time(NULL) - rtc_timestamp;

// convert elapsed time back into rtc registers
word_t d = rtc_registers_time / 86400;
rtc_registers_time %= 86400;

// day overflow
if (d >= 0x0200) {
SET_BIT(gb->mmu->mbc.mbc3.rtc.dh, 7);
d %= 0x0200;
}

gb->mmu->mbc.mbc3.rtc.dh |= (d & 0x100) >> 8;
gb->mmu->mbc.mbc3.rtc.dl = d & 0xFF;
gb->mmu->mbc.mbc3.rtc.dh |= (d & 0x100) >> 8;
gb->mmu->mbc.mbc3.rtc.dl = d & 0xFF;

gb->mmu->mbc.mbc3.rtc.h = rtc_registers_time / 3600;
rtc_registers_time %= 3600;
gb->mmu->mbc.mbc3.rtc.h = rtc_registers_time / 3600;
rtc_registers_time %= 3600;

gb->mmu->mbc.mbc3.rtc.m = rtc_registers_time / 60;
rtc_registers_time %= 60;
gb->mmu->mbc.mbc3.rtc.m = rtc_registers_time / 60;
rtc_registers_time %= 60;

gb->mmu->mbc.mbc3.rtc.s = rtc_registers_time;
}
gb->mmu->mbc.mbc3.rtc.s = rtc_registers_time;

return 1;
}
Expand Down
8 changes: 5 additions & 3 deletions src/core/gb.h
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Original file line number Diff line number Diff line change
Expand Up @@ -44,13 +44,15 @@ static inline void gb_run_frames(gb_t *gb, long frames_limit) {
gb_run_steps(gb, frames_limit * GB_CPU_STEPS_PER_FRAME);
}

int gb_is_rom_valid(const byte_t *rom);

/**
* Inits the emulator.
* @param rom_data a buffer containing the rom the emulator will play.
* @param rom_size the size of the `rom_data`.
* @param rom a buffer containing the rom the emulator will play.
* @param rom_size the size of the `rom`.
* @param opts the initialization options of the emulator or NULL for defaults.
*/
gb_t *gb_init(const byte_t *rom_data, size_t rom_size, gb_options_t *opts);
gb_t *gb_init(const byte_t *rom, size_t rom_size, gb_options_t *opts);

/**
* Quits the emulator gracefully (save eram into a '.sav' file, ...).
Expand Down
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