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More accurate STAT interrupt. This fixes Altered Space and partially fixes Pinball Deluxe. It breaks GBVideoPlayer, however.

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This commit is contained in:
Lior Halphon 2016-06-10 16:31:57 +03:00
parent 3e1863ec51
commit aca5873de2
2 changed files with 27 additions and 24 deletions
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48
Core/display.c
View File

@ -250,6 +250,13 @@ void display_run(GB_gameboy_t *gb)
*/
unsigned char last_mode = gb->io_registers[GB_IO_STAT] & 3;
/*
STAT interrupt is implemented based on this finding:
http://board.byuu.org/phpbb3/viewtopic.php?p=25527#p25531
*/
unsigned char previous_stat_interrupt_line = gb->stat_interrupt_line;
gb->stat_interrupt_line = false;
if (gb->display_cycles >= LCDC_PERIOD) {
/* VBlank! */
gb->display_cycles -= LCDC_PERIOD;
@ -278,14 +285,10 @@ void display_run(GB_gameboy_t *gb)
gb->io_registers[GB_IO_LY] = gb->display_cycles / 456;
bool previous_coincidence_flag = gb->io_registers[GB_IO_STAT] & 4;
gb->io_registers[GB_IO_STAT] &= ~4;
if (gb->io_registers[GB_IO_LY] == gb->io_registers[GB_IO_LYC]) {
gb->io_registers[GB_IO_STAT] |= 4;
if ((gb->io_registers[GB_IO_STAT] & 0x40) && !previous_coincidence_flag) { /* User requests an interrupt on coincidence*/
gb->io_registers[GB_IO_IF] |= 2;
}
gb->stat_interrupt_line = true;
}
/* Todo: This behavior is seen in BGB and it fixes some ROMs with delicate timing, such as Hitman's 8bit.
@ -299,10 +302,10 @@ void display_run(GB_gameboy_t *gb)
gb->effective_window_enabled = false;
gb->effective_window_y = 0xFF;
if (gb->io_registers[GB_IO_STAT] & 16) { /* User requests an interrupt on VBlank*/
gb->stat_interrupt_line = true;
}
if (last_mode != 1) {
if (gb->io_registers[GB_IO_STAT] & 16) { /* User requests an interrupt on VBlank*/
gb->io_registers[GB_IO_IF] |= 2;
}
gb->io_registers[GB_IO_IF] |= 1;
}
@ -328,7 +331,7 @@ void display_run(GB_gameboy_t *gb)
}
}
return;
goto updateSTAT;
}
// Todo: verify this window behavior. It is assumed from the expected behavior of 007 - The World Is Not Enough.
@ -338,16 +341,11 @@ void display_run(GB_gameboy_t *gb)
if (gb->display_cycles % 456 < 80) { /* Mode 2 */
gb->io_registers[GB_IO_STAT] |= 2; /* Set mode to 2 */
if (last_mode != 2) {
if (gb->io_registers[GB_IO_STAT] & 0x20) { /* User requests an interrupt on Mode 2 */
gb->io_registers[GB_IO_IF] |= 2;
}
/* User requests an interrupt on LY=LYC*/
if (gb->io_registers[GB_IO_STAT] & 64 && gb->io_registers[GB_IO_STAT] & 4) {
gb->io_registers[GB_IO_IF] |= 2;
}
if (gb->io_registers[GB_IO_STAT] & 0x20) { /* User requests an interrupt on Mode 2 */
gb->stat_interrupt_line = true;
}
/* See above comment about window behavior. */
if (gb->effective_window_enabled && gb->effective_window_y == 0xFF) {
gb->effective_window_y = gb->io_registers[GB_IO_LY];
@ -355,7 +353,7 @@ void display_run(GB_gameboy_t *gb)
/* Todo: Figure out how the Gameboy handles in-line changes to SCX */
gb->line_x_bias = - (gb->io_registers[GB_IO_SCX] & 0x7);
gb->previous_lcdc_x = gb->line_x_bias;
return;
goto updateSTAT;
}
signed short current_lcdc_x = ((gb->display_cycles % 456 - 80) & ~7) + gb->line_x_bias;
@ -372,19 +370,23 @@ void display_run(GB_gameboy_t *gb)
if (gb->display_cycles % 456 < 80 + 172) { /* Mode 3 */
gb->io_registers[GB_IO_STAT] |= 3; /* Set mode to 3 */
return;
goto updateSTAT;
}
/* if (gb->display_cycles % 456 < 80 + 172 + 204) */ { /* Mode 0*/
if (gb->io_registers[GB_IO_STAT] & 8) { /* User requests an interrupt on Mode 0 */
gb->stat_interrupt_line = true;
}
if (last_mode != 0) {
if (gb->io_registers[GB_IO_STAT] & 8) { /* User requests an interrupt on Mode 0 */
gb->io_registers[GB_IO_IF] |= 2;
}
if (gb->hdma_on_hblank) {
gb->hdma_on = true;
gb->hdma_cycles = 0;
}
}
return;
}
updateSTAT:
if (gb->stat_interrupt_line && !previous_stat_interrupt_line) {
gb->io_registers[GB_IO_IF] |= 2;
}
}

3
Core/gb.h
View File

@ -6,7 +6,7 @@
#include <time.h>
#include "apu.h"
#define GB_STRUCT_VERSION 6
#define GB_STRUCT_VERSION 7
enum {
GB_REGISTER_AF,
@ -225,6 +225,7 @@ typedef struct GB_gameboy_s{
signed short line_x_bias;
bool effective_window_enabled;
unsigned char effective_window_y;
bool stat_interrupt_line;
unsigned char bios[0x900];
bool bios_finished;