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Refactor FIFOs

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This commit is contained in:
Lior Halphon 2022-05-07 19:27:25 +03:00
parent 69a5ed3396
commit ac29b4391e
3 changed files with 24 additions and 35 deletions
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49
Core/display.c
View File

@ -9,12 +9,12 @@
static inline unsigned fifo_size(GB_fifo_t *fifo)
{
return (fifo->write_end - fifo->read_end) & (GB_FIFO_LENGTH - 1);
return fifo->size;
}
static void fifo_clear(GB_fifo_t *fifo)
{
fifo->read_end = fifo->write_end = 0;
fifo->read_end = fifo->size = 0;
}
static GB_fifo_item_t *fifo_pop(GB_fifo_t *fifo)
@ -22,14 +22,17 @@ static GB_fifo_item_t *fifo_pop(GB_fifo_t *fifo)
GB_fifo_item_t *ret = &fifo->fifo[fifo->read_end];
fifo->read_end++;
fifo->read_end &= (GB_FIFO_LENGTH - 1);
fifo->size--;
return ret;
}
static void fifo_push_bg_row(GB_fifo_t *fifo, uint8_t lower, uint8_t upper, uint8_t palette, bool bg_priority, bool flip_x)
{
assert(fifo->size == 0);
fifo->size = 8;
if (!flip_x) {
unrolled for (unsigned i = 8; i--;) {
fifo->fifo[fifo->write_end] = (GB_fifo_item_t) {
unrolled for (unsigned i = 0; i < 8; i++) {
fifo->fifo[i] = (GB_fifo_item_t) {
(lower >> 7) | ((upper >> 7) << 1),
palette,
0,
@ -37,14 +40,11 @@ static void fifo_push_bg_row(GB_fifo_t *fifo, uint8_t lower, uint8_t upper, uint
};
lower <<= 1;
upper <<= 1;
fifo->write_end++;
fifo->write_end &= (GB_FIFO_LENGTH - 1);
}
}
else {
unrolled for (unsigned i = 8; i--;) {
fifo->fifo[fifo->write_end] = (GB_fifo_item_t) {
unrolled for (unsigned i = 0; i < 8; i++) {
fifo->fifo[i] = (GB_fifo_item_t) {
(lower & 1) | ((upper & 1) << 1),
palette,
0,
@ -52,19 +52,15 @@ static void fifo_push_bg_row(GB_fifo_t *fifo, uint8_t lower, uint8_t upper, uint
};
lower >>= 1;
upper >>= 1;
fifo->write_end++;
fifo->write_end &= (GB_FIFO_LENGTH - 1);
}
}
}
static void fifo_overlay_object_row(GB_fifo_t *fifo, uint8_t lower, uint8_t upper, uint8_t palette, bool bg_priority, uint8_t priority, bool flip_x)
{
while (fifo_size(fifo) < 8) {
fifo->fifo[fifo->write_end] = (GB_fifo_item_t) {0,};
fifo->write_end++;
fifo->write_end &= (GB_FIFO_LENGTH - 1);
while (fifo->size < GB_FIFO_LENGTH) {
fifo->fifo[(fifo->read_end + fifo->size) & (GB_FIFO_LENGTH - 1)] = (GB_fifo_item_t) {0,};
fifo->size++;
}
uint8_t flip_xor = flip_x? 0: 0x7;
@ -557,21 +553,16 @@ static void render_pixel_if_possible(GB_gameboy_t *gb)
bool draw_oam = false;
bool bg_enabled = true, bg_priority = false;
if (fifo_size(&gb->bg_fifo)) {
fifo_item = fifo_pop(&gb->bg_fifo);
bg_priority = fifo_item->bg_priority;
if (fifo_size(&gb->oam_fifo)) {
oam_fifo_item = fifo_pop(&gb->oam_fifo);
if (oam_fifo_item->pixel && (gb->io_registers[GB_IO_LCDC] & 2) && unlikely(!gb->objects_disabled)) {
draw_oam = true;
bg_priority |= oam_fifo_item->bg_priority;
}
fifo_item = fifo_pop(&gb->bg_fifo);
bg_priority = fifo_item->bg_priority;
if (fifo_size(&gb->oam_fifo)) {
oam_fifo_item = fifo_pop(&gb->oam_fifo);
if (oam_fifo_item->pixel && (gb->io_registers[GB_IO_LCDC] & 2) && unlikely(!gb->objects_disabled)) {
draw_oam = true;
bg_priority |= oam_fifo_item->bg_priority;
}
}
if (!fifo_item) return;
/* Drop pixels for scrollings */
if (gb->position_in_line >= 160 || (gb->disable_rendering && !gb->sgb)) {

4
Core/gb.h
View File

@ -311,11 +311,11 @@ typedef struct {
bool bg_priority; // For object FIFO – the BG priority bit. For the BG FIFO – the CGB attributes priority bit
} GB_fifo_item_t;
#define GB_FIFO_LENGTH 16
#define GB_FIFO_LENGTH 8
typedef struct {
GB_fifo_item_t fifo[GB_FIFO_LENGTH];
uint8_t read_end;
uint8_t write_end;
uint8_t size;
} GB_fifo_t;
typedef struct {

6
Core/save_state.c
View File

@ -342,10 +342,8 @@ static void sanitize_state(GB_gameboy_t *gb)
GB_palette_changed(gb, true, i * 2);
}
gb->bg_fifo.read_end &= 0xF;
gb->bg_fifo.write_end &= 0xF;
gb->oam_fifo.read_end &= 0xF;
gb->oam_fifo.write_end &= 0xF;
gb->bg_fifo.read_end &= GB_FIFO_LENGTH - 1;
gb->oam_fifo.read_end &= GB_FIFO_LENGTH - 1;
gb->last_tile_index_address &= 0x1FFF;
gb->window_tile_x &= 0x1F;