mirror of https://github.com/bsnes-emu/bsnes.git
It appears that OAM DMA blocks PPU access to OAM
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@ -306,6 +306,11 @@ static void add_object_from_index(GB_gameboy_t *gb, unsigned index)
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{
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{
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if (gb->n_visible_objs == 10) return;
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if (gb->n_visible_objs == 10) return;
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/* TODO: It appears that DMA blocks PPU access to OAM, but it needs verification. */
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if (gb->dma_steps_left && (gb->dma_cycles >= 0 || gb->is_dma_restarting)) {
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return;
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}
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/* This reverse sorts the visible objects by location and priority */
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/* This reverse sorts the visible objects by location and priority */
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GB_object_t *objects = (GB_object_t *) &gb->oam;
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GB_object_t *objects = (GB_object_t *) &gb->oam;
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bool height_16 = (gb->io_registers[GB_IO_LCDC] & 4) != 0;
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bool height_16 = (gb->io_registers[GB_IO_LCDC] & 4) != 0;
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@ -729,7 +734,9 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
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gb->cycles_for_line += 6;
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gb->cycles_for_line += 6;
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GB_SLEEP(gb, display, 20, 6);
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GB_SLEEP(gb, display, 20, 6);
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/* TODO: what does the PPU read if DMA is active? */
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GB_object_t *object = &objects[gb->visible_objs[gb->n_visible_objs - 1]];
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GB_object_t *object = &objects[gb->visible_objs[gb->n_visible_objs - 1]];
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bool height_16 = (gb->io_registers[GB_IO_LCDC] & 4) != 0; /* Todo: Which T-cycle actually reads this? */
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bool height_16 = (gb->io_registers[GB_IO_LCDC] & 4) != 0; /* Todo: Which T-cycle actually reads this? */
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uint8_t tile_y = (gb->current_line - object->y) & (height_16? 0xF : 7);
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uint8_t tile_y = (gb->current_line - object->y) & (height_16? 0xF : 7);
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