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apps,litenes,ppu: use uint16_t for XHL table, instead of uint64_t

This commit is contained in:
Zihao Yu 2019-04-27 20:04:38 +08:00
parent 107eaf04b1
commit 7e645c1382
1 changed files with 20 additions and 32 deletions
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52
apps/litenes/src/ppu.c
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@ -16,15 +16,16 @@ byte ppu_addr_latch;
PPU_STATE ppu;
byte ppu_latch;
bool ppu_sprite_hit_occured = false;
byte ppu_screen_background[264][264];
uint16_t ppu_screen_background[264][264 / 8];
// preprocess tables
static byte XHL[256][256][8]; // each valus is 0~3
static uint64_t XHL64[256][256];
static uint64_t XHLmask[256][256];
static uint32_t ppu_ram_map[0x4000];
static uint16_t XHL16[256][256];
static uint16_t XHLmask16[256][256];
// PPUCTRL Functions
static uint32_t base_nametable_address;
@ -161,20 +162,6 @@ int ppu_read_idx(void) {
// 3F1F = 11 (00010001)
// 3F20 = 2B (00101011)
static inline uint64_t int_shl(int n, int s) {
// compute (uint64_t)n << s without generating shld instruction in x86
int hi, lo;
if (s < 32) {
lo = n << s;
hi = (s == 0 ? 0 : n >> (32 - s));
}
else {
lo = 0;
hi = n << (s - 32);
}
return ((uint64_t)hi << 32) | lo;
}
// Rendering
static void table_init() {
for (int h = 0; h < 256; h ++)
@ -182,9 +169,9 @@ static void table_init() {
for (int x = 0; x < 8; x ++) {
int col = (((h >> (7 - x)) & 1) << 1) | ((l >> (7 - x)) & 1);
XHL[h][l][x] = col;
XHL64[h][l] |= int_shl(col, x * 8);
XHL16[h][l] |= col << (x * 2);
if (col == 0) {
XHLmask[h][l] |= int_shl(0xff,x * 8);
XHLmask16[h][l] |= 0x3 << (x * 2);
}
}
}
@ -255,28 +242,25 @@ void ppu_draw_background_scanline(bool mirror) {
uint32_t l = ppu_ram_read_fast(tile_address + y_in_tile);
uint32_t h = ppu_ram_read_fast(tile_address + y_in_tile + 8);
if (do_update && ppu.scanline < H) {
uint32_t color16 = XHL16[h][l];
uint16_t *ptr = &ppu_screen_background[ppu.scanline][tile_x];
*ptr = color16 | (XHLmask16[h][l] & (*ptr)) ;
if (do_update) {
uint32_t palette_attribute = palette_attr_cache[(ppu.PPUCTRL & 0x3) + mirror]
[top][ppu.scanline >> 5][tile_x >> 2];
int *palette_cache_line = palette_cache[palette_attribute];
union {
uint64_t u64;
byte color[8];
} buf;
buf.u64 = XHL64[h][l];
#define macro(x) \
if (buf.color[x] != 0) { \
draw(scroll_base + x, ppu.scanline + 1, palette_cache_line[buf.color[x]]); \
}
if ((color16 & 0x3) != 0) { \
draw(scroll_base + x, ppu.scanline + 1, palette_cache_line[color16 & 0x3]); \
} \
color16 >>= 2;
// loop unrolling
macro(0); macro(1); macro(2); macro(3);
macro(4); macro(5); macro(6); macro(7);
}
uint64_t *ptr = (uint64_t*)&ppu_screen_background[ppu.scanline][(tile_x << 3)];
*ptr = (XHL64[h][l]) | (XHLmask[h][l] & (*ptr)) ;
taddr ++;
scroll_base += 8;
@ -337,9 +321,13 @@ void ppu_draw_sprite_scanline() {
}
// Checking sprite 0 hit
if (n == 0 && !ppu_sprite_hit_occured && ppu_shows_background() && ppu_screen_background[sprite_y + y_in_tile][screen_x] == color) {
if (!ppu_sprite_hit_occured && n == 0 && ppu_shows_background()) {
uint32_t bg16 = ppu_screen_background[sprite_y + y_in_tile][screen_x >> 3];
uint32_t bg = (bg16 >> ((screen_x & 0x7) * 2)) & 0x3;
if (bg == color) {
ppu_set_sprite_0_hit(true);
ppu_sprite_hit_occured = true;
}
}
}
}