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More sensible implementation of the STAT interrupt.

This commit is contained in:
Lior Halphon 2018-06-04 02:07:38 +03:00
parent 8f892ab798
commit f1dfa2a1bc
2 changed files with 27 additions and 44 deletions
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68
Core/display.c
View File

@ -230,21 +230,12 @@ void GB_set_color_correction_mode(GB_gameboy_t *gb, GB_color_correction_mode_t m
*/
static void trigger_oam_interrupt(GB_gameboy_t *gb)
{
if (!gb->stat_interrupt_line && gb->oam_interrupt_line) {
gb->io_registers[GB_IO_IF] |= 2;
gb->stat_interrupt_line = true;
}
}
/* Todo: When the CPU and PPU write to IF at the same T-cycle, the PPU write is ignored. */
void GB_STAT_update(GB_gameboy_t *gb)
{
if (!(gb->io_registers[GB_IO_LCDC] & 0x80)) return;
bool previous_interrupt_line = gb->stat_interrupt_line | gb->oam_interrupt_line;
gb->stat_interrupt_line = gb->oam_interrupt_line;
bool previous_interrupt_line = gb->stat_interrupt_line;
/* Set LY=LYC bit */
if (gb->ly_for_comparison != (uint16_t)-1 || !gb->is_cgb) {
if (gb->ly_for_comparison == gb->io_registers[GB_IO_LYC]) {
@ -259,12 +250,11 @@ void GB_STAT_update(GB_gameboy_t *gb)
}
}
switch (gb->io_registers[GB_IO_STAT] & 3) {
case 0: gb->stat_interrupt_line = (gb->io_registers[GB_IO_STAT] & 8) && !gb->mode_0_interrupt_disable; break;
switch (gb->mode_for_interrupt) {
case 0: gb->stat_interrupt_line = gb->io_registers[GB_IO_STAT] & 8; break;
case 1: gb->stat_interrupt_line = gb->io_registers[GB_IO_STAT] & 0x10; break;
/* The OAM interrupt is handled differently, it reads the writable flags from STAT less frequenctly,
and is not based on the mode bits of STAT. */
// case 2: gb->stat_interrupt_line = gb->io_registers[GB_IO_STAT] & 0x20; break;
case 2: gb->stat_interrupt_line = gb->io_registers[GB_IO_STAT] & 0x20; break;
default: gb->stat_interrupt_line = false;
}
/* User requested a LY=LYC interrupt and the LY=LYC bit is on */
@ -588,10 +578,10 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
/* Todo: Merge this with the normal line routine */
/* Handle the very first line 0 */
gb->mode_0_interrupt_disable = true;
gb->current_line = 0;
gb->ly_for_comparison = 0;
gb->io_registers[GB_IO_STAT] &= ~3;
gb->mode_for_interrupt = -1;
gb->oam_read_blocked = false;
gb->vram_read_blocked = false;
gb->oam_write_blocked = false;
@ -602,11 +592,11 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
gb->io_registers[GB_IO_STAT] &= ~3;
gb->io_registers[GB_IO_STAT] |= 3;
gb->mode_for_interrupt = 3;
gb->oam_read_blocked = true;
gb->vram_read_blocked = !gb->is_cgb;
gb->oam_write_blocked = true;
gb->vram_write_blocked = !gb->is_cgb;
gb->mode_0_interrupt_disable = false;
GB_STAT_update(gb);
gb->cycles_for_line += 2;
@ -620,6 +610,7 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
if (!gb->cgb_double_speed) {
gb->io_registers[GB_IO_STAT] &= ~3;
gb->mode_for_interrupt = 0;
gb->oam_read_blocked = false;
gb->vram_read_blocked = false;
gb->oam_write_blocked = false;
@ -629,6 +620,7 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
GB_SLEEP(gb, display, 4, 1);
gb->io_registers[GB_IO_STAT] &= ~3;
gb->mode_for_interrupt = 0;
gb->oam_read_blocked = false;
gb->vram_read_blocked = false;
gb->oam_write_blocked = false;
@ -638,7 +630,7 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
/* Mode 0 is shorter in the very first line */
GB_SLEEP(gb, display, 5, LINE_LENGTH - gb->cycles_for_line - 8);
gb->mode_0_interrupt_disable = !(gb->io_registers[GB_IO_STAT] & 0x20);
gb->mode_for_interrupt = 2;
gb->current_line = 1;
while (true) {
/* Lines 0 - 143 */
@ -653,23 +645,23 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
/* The OAM STAT interrupt occurs 1 T-cycle before STAT actually changes, except on line 0.
PPU glitch. */
if (gb->current_line != 0) {
gb->oam_interrupt_line = gb->io_registers[GB_IO_STAT] & 0x20;
}
trigger_oam_interrupt(gb);
GB_STAT_update(gb);
if (gb->current_line != 0 || !gb->is_cgb) {
gb->mode_for_interrupt = 2;
gb->io_registers[GB_IO_STAT] &= ~3;
}
else if (!gb->is_cgb) {
gb->io_registers[GB_IO_STAT] &= ~3;
}
GB_STAT_update(gb);
GB_SLEEP(gb, display, 7, 1);
gb->mode_0_interrupt_disable = false;
gb->io_registers[GB_IO_STAT] &= ~3;
gb->io_registers[GB_IO_STAT] |= 2;
gb->mode_for_interrupt = 2;
gb->oam_write_blocked = true;
gb->ly_for_comparison = gb->current_line;
gb->oam_interrupt_line = gb->io_registers[GB_IO_STAT] & 0x20;
trigger_oam_interrupt(gb);
GB_STAT_update(gb);
gb->mode_for_interrupt = -1;
GB_STAT_update(gb);
gb->n_visible_objs = 0;
@ -693,11 +685,10 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
gb->accessed_oam_row = -1;
gb->io_registers[GB_IO_STAT] &= ~3;
gb->io_registers[GB_IO_STAT] |= 3;
gb->mode_for_interrupt = 3;
gb->vram_read_blocked = true;
gb->vram_write_blocked = true;
gb->oam_write_blocked = true;
gb->oam_interrupt_line = false;
trigger_oam_interrupt(gb);
GB_STAT_update(gb);
gb->cycles_for_line = MODE2_LENGTH + 4;
@ -803,6 +794,7 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
}
if (!gb->cgb_double_speed) {
gb->io_registers[GB_IO_STAT] &= ~3;
gb->mode_for_interrupt = 0;
gb->oam_read_blocked = false;
gb->vram_read_blocked = false;
gb->oam_write_blocked = false;
@ -813,6 +805,7 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
GB_SLEEP(gb, display, 22, 1);
gb->io_registers[GB_IO_STAT] &= ~3;
gb->mode_for_interrupt = 0;
gb->oam_read_blocked = false;
gb->vram_read_blocked = false;
gb->oam_write_blocked = false;
@ -828,9 +821,7 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
gb->hdma_starting = true;
}
GB_SLEEP(gb, display, 11, LINE_LENGTH - gb->cycles_for_line);
/* Todo: The last cycle of move 0 can't trigger an interrupt... unless OAM interrupt is requested?
This doesn't make too much sense. */
gb->mode_0_interrupt_disable = !(gb->io_registers[GB_IO_STAT] & 0x20);
gb->mode_for_interrupt = 2;
}
/* Lines 144 - 152 */
@ -839,28 +830,21 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
gb->ly_for_comparison = -1;
GB_SLEEP(gb, display, 26, 2);
if (gb->current_line == LINES) {
gb->oam_interrupt_line = gb->io_registers[GB_IO_STAT] & 0x20;
trigger_oam_interrupt(gb);
gb->mode_for_interrupt = 2;
}
GB_STAT_update(gb);
gb->oam_interrupt_line = false;
GB_SLEEP(gb, display, 12, 2);
gb->ly_for_comparison = gb->current_line;
if (gb->current_line == LINES) {
/* Entering VBlank state triggers the OAM interrupt */
gb->oam_interrupt_line = gb->io_registers[GB_IO_STAT] & 0x20;
gb->io_registers[GB_IO_STAT] &= ~3;
gb->io_registers[GB_IO_STAT] |= 1;
gb->io_registers[GB_IO_IF] |= 1;
gb->mode_0_interrupt_disable = false;
trigger_oam_interrupt(gb);
gb->mode_for_interrupt = 2;
GB_STAT_update(gb);
gb->mode_for_interrupt = 1;
GB_STAT_update(gb);
gb->oam_interrupt_line = false;
if (gb->io_registers[GB_IO_STAT] & 0x20) {
gb->stat_interrupt_line = true;
}
if (gb->frame_skip_state == GB_FRAMESKIP_LCD_TURNED_ON) {
display_vblank(gb);

3
Core/gb.h
View File

@ -422,8 +422,7 @@ struct GB_gameboy_internal_s {
uint8_t oam_search_index;
uint8_t accessed_oam_row;
uint8_t extra_penalty_for_sprite_at_0;
bool mode_0_interrupt_disable;
bool oam_interrupt_line;
uint8_t mode_for_interrupt;
bool lyc_interrupt_line;
);