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Updated SameBoy to pass Mooneye-GB’s lcdon_timing test (on a DMG), as well as refined related CBG behaviors.

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This commit is contained in:
Lior Halphon 2017-06-17 22:17:58 +03:00
parent bbd2ca8ddf
commit 86c9f9d89d
3 changed files with 64 additions and 10 deletions
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60
Core/display.c
View File

@ -266,6 +266,9 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
gb->hdma_steps_left = 0xff;
}
gb->oam_blocked = false;
gb->vram_blocked = false;
/* Keep sending vblanks to user even if the screen is off */
gb->display_cycles += cycles;
if (gb->display_cycles >= LCDC_PERIOD) {
@ -281,14 +284,25 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
uint8_t atomic_increase = gb->cgb_double_speed? 2 : 4;
uint8_t stat_delay = gb->cgb_double_speed? 2 : (gb->cgb_mode? 0 : 4);
/* This is correct for DMG. Is it correct for the 3 CGB modes (DMG/single/double)?*/
/* Todo: This is correct for DMG. Is it correct for the 3 CGB modes (DMG/single/double)?*/
uint8_t scx_delay = ((gb->effective_scx & 7) + atomic_increase - 1) & ~(atomic_increase - 1);
/* Todo: These are correct for DMG, DMG-mode CGB, and single speed CGB. Is is correct for double speed CGB? */
uint8_t oam_blocking_rush = gb->cgb_double_speed? 2 : 4;
uint8_t vram_blocking_rush = gb->is_cgb? 0 : 4;
for (; cycles; cycles -= atomic_increase) {
gb->display_cycles += atomic_increase;
/* The very first line is 2 (4 from the CPU's perseptive) clocks shorter when the LCD turns on.
Todo: Verify on the 3 CGB modes, especially double speed mode. */
if (gb->first_scanline && gb->display_cycles >= LINE_LENGTH - atomic_increase) {
gb->first_scanline = false;
gb->display_cycles += atomic_increase;
}
bool should_compare_ly = true;
uint8_t ly_for_comparison = gb->io_registers[GB_IO_LY] = gb->display_cycles / LINE_LENGTH;
/* Handle cycle completion. STAT's initial value depends on model and mode */
if (gb->display_cycles == LCDC_PERIOD) {
/* VBlank! */
@ -304,6 +318,10 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
}
ly_for_comparison = gb->io_registers[GB_IO_LY] = 0;
/* Todo: verify timing */
gb->oam_blocked = true;
gb->vram_blocked = false;
/* Reset window rendering state */
gb->current_window_line = 0xFF;
}
@ -333,9 +351,42 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
}
}
/* Handle line 0 right after turning the LCD on */
else if (gb->first_scanline) {
/* OAM and VRAM blocking is not delayed in the very first scanline */
if (gb->display_cycles == atomic_increase) {
gb->io_registers[GB_IO_STAT] &= ~3;
gb->oam_blocked = false;
gb->vram_blocked = false;
}
else if (gb->display_cycles == MODE2_LENGTH) {
gb->io_registers[GB_IO_STAT] &= ~3;
gb->io_registers[GB_IO_STAT] |= 3;
gb->oam_blocked = true;
gb->vram_blocked = true;
}
else if (gb->display_cycles == MODE2_LENGTH + MODE3_LENGTH) {
gb->io_registers[GB_IO_STAT] &= ~3;
gb->oam_blocked = false;
gb->vram_blocked = false;
}
}
/* Handle STAT changes for lines 0-143 */
else if (gb->display_cycles < LINES * LINE_LENGTH ) {
else if (gb->display_cycles < LINES * LINE_LENGTH) {
unsigned position_in_line = gb->display_cycles % LINE_LENGTH;
/* Handle OAM and VRAM blocking */
if (position_in_line == stat_delay - oam_blocking_rush ||
// In case stat_delay is 0
(position_in_line == LINE_LENGTH + stat_delay - oam_blocking_rush && gb->io_registers[GB_IO_LY] != 143)) {
gb->oam_blocked = true;
}
else if (position_in_line == MODE2_LENGTH + stat_delay - vram_blocking_rush) {
gb->vram_blocked = true;
}
/* Handle everything else */
if (position_in_line == stat_delay) {
gb->io_registers[GB_IO_STAT] &= ~3;
gb->io_registers[GB_IO_STAT] |= 2;
@ -360,6 +411,8 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
}
else if (position_in_line == MODE2_LENGTH + MODE3_LENGTH + stat_delay + scx_delay) {
gb->io_registers[GB_IO_STAT] &= ~3;
gb->vram_blocked = false;
gb->oam_blocked = false;
if (gb->hdma_on_hblank) {
gb->hdma_on = true;
gb->hdma_cycles = 0;
@ -466,9 +519,6 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
gb->stat_interrupt_line = true;
}
}
if (!gb->stat_interrupt_line) {
}
}
if (gb->stat_interrupt_line && !previous_stat_interrupt_line) {

3
Core/gb.h
View File

@ -375,6 +375,9 @@ struct GB_gameboy_internal_s {
GB_FRAMESKIP_FIRST_FRAME_SKIPPED, // This state is 'skipped' when emulating a DMG
GB_FRAMESKIP_SECOND_FRAME_RENDERED,
} frame_skip_state;
bool first_scanline; // The very first scan line after turning the LCD behaves differently.
bool oam_blocked;
bool vram_blocked;
);
/* Unsaved data. This includes all pointers, as well as everything that shouldn't be on a save state */

11
Core/memory.c
View File

@ -60,7 +60,7 @@ static uint8_t read_mbc_rom(GB_gameboy_t *gb, uint16_t addr)
static uint8_t read_vram(GB_gameboy_t *gb, uint16_t addr)
{
if ((gb->io_registers[GB_IO_STAT] & 0x3) == 3) {
if (gb->vram_blocked) {
return 0xFF;
}
return gb->vram[(addr & 0x1FFF) + (uint16_t) gb->cgb_vram_bank * 0x2000];
@ -115,7 +115,7 @@ static uint8_t read_high_memory(GB_gameboy_t *gb, uint16_t addr)
}
if (addr < 0xFEA0) {
if ((gb->io_registers[GB_IO_STAT] & 0x3) >= 2 || (gb->dma_steps_left && (gb->dma_cycles > 0 || gb->is_dma_restarting))) {
if (gb->oam_blocked || (gb->dma_steps_left && (gb->dma_cycles > 0 || gb->is_dma_restarting))) {
return 0xFF;
}
return gb->oam[addr & 0xFF];
@ -338,7 +338,7 @@ static void write_mbc(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
static void write_vram(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
{
if ((gb->io_registers[GB_IO_STAT] & 0x3) == 3) {
if (gb->vram_blocked) {
//GB_log(gb, "Wrote %02x to %04x (VRAM) during mode 3\n", value, addr);
return;
}
@ -385,7 +385,7 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
}
if (addr < 0xFEA0) {
if ((gb->io_registers[GB_IO_STAT] & 0x3) >= 2 || (gb->dma_steps_left && (gb->dma_cycles > 0 || gb->is_dma_restarting))) {
if (gb->oam_blocked|| (gb->dma_steps_left && (gb->dma_cycles > 0 || gb->is_dma_restarting))) {
return;
}
gb->oam[addr & 0xFF] = value;
@ -438,7 +438,8 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
if ((value & 0x80) && !(gb->io_registers[GB_IO_LCDC] & 0x80)) {
/* It appears that there's a slight delay after enabling the screen? */
/* Todo: verify this. */
gb->display_cycles = gb->cgb_double_speed? -2 : -4;
gb->display_cycles = 0;
gb->first_scanline = true;
if (gb->frame_skip_state == GB_FRAMESKIP_SECOND_FRAME_RENDERED) {
gb->frame_skip_state = GB_FRAMESKIP_LCD_TURNED_ON;
}