git.y1.nz

commit ac9e36bc1a6cda92a0ff8f7f59057cc26558da13
parent e49527eff8e99c1137c3c87d8916a95a87512d5e
Author: Lior Halphon <LIJI32@gmail.com>
Date:   Sun, 16 Oct 2022 18:19:43 +0300

Fix assertion regression, fix window pixel insertion glitch regression, remove dead code. Closes #504

Diffstat:
M
Core/display.c
21
++++++---------------
M
Core/gb.h
1
+
M
Core/sm83_cpu.c
4
++++

3 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/Core/display.c b/Core/display.c
@@ -20,6 +20,7 @@ static void fifo_clear(GB_fifo_t *fifo)
 static GB_fifo_item_t *fifo_pop(GB_fifo_t *fifo)
 {
     assert(fifo->size);
+    assert(fifo->size <= 8);
     GB_fifo_item_t *ret = &fifo->fifo[fifo->read_end];
     fifo->read_end++;
     fifo->read_end &= (GB_FIFO_LENGTH - 1);
@@ -602,7 +603,7 @@ static void render_pixel_if_possible(GB_gameboy_t *gb)
         return;
     }
     
-    if (unlikely(gb->wx_triggered && !fifo_size(&gb->bg_fifo))) return;
+    if (unlikely(!fifo_size(&gb->bg_fifo))) return;
     
     fifo_item = fifo_pop(&gb->bg_fifo);
     bg_priority = fifo_item->bg_priority;
@@ -946,7 +947,7 @@ static void advance_fetcher_state_machine(GB_gameboy_t *gb, unsigned *cycles)
             }
             if (fifo_size(&gb->bg_fifo) > 0) break;
             
-            if (unlikely(gb->wy_triggered && !(gb->io_registers[GB_IO_LCDC] & GB_LCDC_WIN_ENABLE) && !GB_is_cgb(gb))) {
+            if (unlikely(gb->wy_triggered && !(gb->io_registers[GB_IO_LCDC] & GB_LCDC_WIN_ENABLE) && !GB_is_cgb(gb) && !gb->disable_window_pixel_insertion_glitch)) {
                 /* See https://github.com/LIJI32/SameBoy/issues/278 for documentation */
                 uint8_t logical_position = gb->position_in_line + 7;
                 if (logical_position > 167) {
@@ -1665,6 +1666,7 @@ void GB_display_run(GB_gameboy_t *gb, unsigned cycles, bool force)
             gb->cycles_for_line += 2;
             GB_SLEEP(gb, display, 32, 2);
         mode_3_start:
+            gb->disable_window_pixel_insertion_glitch = false;
             /* TODO: Timing seems incorrect, might need an access conflict handling. */
             if ((gb->io_registers[GB_IO_LCDC] & GB_LCDC_WIN_ENABLE) &&
                 gb->io_registers[GB_IO_WY] == gb->current_line) {
@@ -1750,17 +1752,6 @@ void GB_display_run(GB_gameboy_t *gb, unsigned cycles, bool force)
                         gb->window_y++;
                     }
                 }
-                
-                /* TODO: What happens when WX=0? When the fifo is full? */
-                if (!GB_is_cgb(gb) && gb->wx_triggered && !gb->window_is_being_fetched &&
-                    gb->fetcher_state == 0 && gb->io_registers[GB_IO_WX] == (uint8_t) (gb->position_in_line + 7) && gb->bg_fifo.size == 8) {
-                    // Insert a pixel right at the FIFO's end
-                    gb->bg_fifo.read_end--;
-                    gb->bg_fifo.read_end &= GB_FIFO_LENGTH - 1;
-                    gb->bg_fifo.fifo[gb->bg_fifo.read_end] = (GB_fifo_item_t){0,};
-                    gb->bg_fifo.size++;
-                    gb->window_is_being_fetched = false;
-                }
 
                 /* Handle objects */
                 /* When the object enabled bit is off, this proccess is skipped entirely on the DMG, but not on the CGB.
@@ -1872,7 +1863,7 @@ skip_slow_mode_3:
             }
             */
             while (gb->lcd_x != 160 && !gb->disable_rendering && gb->screen && !gb->sgb) {
-                /* Oh no! The PPU and LCD desynced! Fill the rest of the line whith white. */
+                /* Oh no! The PPU and LCD desynced! Fill the rest of the line with the last color. */
                 uint32_t *dest = NULL;
                 if (gb->border_mode != GB_BORDER_ALWAYS) {
                     dest = gb->screen + gb->lcd_x + gb->current_line * WIDTH;
@@ -1880,7 +1871,7 @@ skip_slow_mode_3:
                 else {
                     dest = gb->screen + gb->lcd_x + gb->current_line * BORDERED_WIDTH + (BORDERED_WIDTH - WIDTH) / 2 + (BORDERED_HEIGHT - LINES) / 2 * BORDERED_WIDTH;
                 }
-                *dest = gb->background_palettes_rgb[0];
+                *dest = (gb->lcd_x == 0)? gb->background_palettes_rgb[0] : dest[-1];
                 gb->lcd_x++;
 
             }
diff --git a/Core/gb.h b/Core/gb.h
@@ -667,6 +667,7 @@ struct GB_gameboy_internal_s {
         uint8_t data_for_sel_glitch;
         bool delayed_glitch_hblank_interrupt;
         uint32_t frame_repeat_countdown;
+        bool disable_window_pixel_insertion_glitch;
     )
 
     /* Unsaved data. This includes all pointers, as well as everything that shouldn't be on a save state */
diff --git a/Core/sm83_cpu.c b/Core/sm83_cpu.c
@@ -214,6 +214,10 @@ static void cycle_write(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
             GB_write_memory(gb, addr, old_value | (value & GB_LCDC_BG_EN));
             GB_advance_cycles(gb, 1);
             GB_write_memory(gb, addr, value);
+            
+            if ((old_value & GB_LCDC_WIN_ENABLE) && !(value & GB_LCDC_WIN_ENABLE) && gb->window_is_being_fetched) {
+                gb->disable_window_pixel_insertion_glitch = true;
+            }
             gb->pending_cycles = 5;
             break;
         }

This webpage is intended to be an accessible preview of this repository. To get a fuller picture, clone it and use the git CLI.