Max/SameBoy
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Fixed timing when turning the LCD display on during double speed mode

Browse Source
This commit is contained in:
Lior Halphon 2017-09-02 22:11:38 +03:00
parent 54eb51d8db
commit 9b490396bb
2 changed files with 4 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Core/display.c
View File

@ -299,11 +299,11 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
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) {
/* The very first line is 4 clocks shorter when the LCD turns on. Verified on SGB2, CGB in CGB mode and
CGB in double speed mode. */
if (gb->first_scanline && gb->display_cycles >= LINE_LENGTH - 4) {
gb->first_scanline = false;
gb->display_cycles += atomic_increase;
gb->display_cycles += 4;
}
bool should_compare_ly = true;
uint8_t ly_for_comparison = gb->io_registers[GB_IO_LY] = gb->display_cycles / LINE_LENGTH;

2
Core/memory.c
View File

@ -454,8 +454,6 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
case GB_IO_LCDC:
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 = 0;
gb->first_scanline = true;
if (gb->frame_skip_state == GB_FRAMESKIP_SECOND_FRAME_RENDERED) {