diff options
Diffstat (limited to 'mknes_ppu.c')
| -rw-r--r-- | mknes_ppu.c | 88 |
1 files changed, 0 insertions, 88 deletions
diff --git a/mknes_ppu.c b/mknes_ppu.c index b00e380..870439b 100644 --- a/mknes_ppu.c +++ b/mknes_ppu.c @@ -109,93 +109,6 @@ static inline void ppu_fetch_sprite_patterns(struct nes_state * restrict state, } } - -#if 0 -// layout reminder -// struct sprite_data { u8 shift_lo, shift_hi, position, priority, palette; } __attribute__((packed)); - -__attribute__((always_inline, hot, optimize("no-jump-tables","no-unroll-loops"))) -static inline void ppu_render_pixel(struct nes_state * restrict state, uint32_t x, uint32_t y, uint8_t mask_reg) { - struct ppu_state *restrict ppu = &state->ppu; - - // 32-bit temps for bg path; keep struct 16-bit/8-bit - const uint32_t s = 15u - (uint32_t)ppu->fine_x; - const uint32_t show_bg = (mask_reg & PPU_MASK_SHOW_BG) != 0; - const uint32_t show_sprites = (mask_reg & PPU_MASK_SHOW_SPRITES) != 0; - const uint32_t left_bg = (mask_reg & 0x02) != 0; - const uint32_t left_sp = (mask_reg & 0x04) != 0; - const uint32_t x_ge_8 = (x & ~7u) != 0; - - const uint32_t bg_on = show_bg & (left_bg | x_ge_8); - const uint32_t sp_on = show_sprites & (left_sp | x_ge_8); - - const uint32_t pat_lo = (uint32_t)ppu->bg_shift_pattern_low; - const uint32_t pat_hi = (uint32_t)ppu->bg_shift_pattern_high; - const uint32_t att_lo = (uint32_t)ppu->bg_shift_attrib_low; - const uint32_t att_hi = (uint32_t)ppu->bg_shift_attrib_high; - - const uint32_t p0 = (pat_lo >> s) & 1u; - const uint32_t p1 = (pat_hi >> s) & 1u; - const uint32_t a0 = (att_lo >> s) & 1u; - const uint32_t a1 = (att_hi >> s) & 1u; - - const uint32_t bg_pixel = ((p1 << 1) | p0) & -bg_on; - const uint32_t bg_palette = ((a1 << 1) | a0) & -bg_on; - - // Sprite resolve: only load fields in this order: - // position (branch filter) -> shift bytes (pixel test) -> meta (on hit) - uint32_t sp_pixel = 0, sp_palette = 0, sp_prio = 0, sp_zero = 0; - - if (sp_on) { - struct sprite_data * restrict s_ptr = ppu->sprites; // address calc only - uint32_t n = ppu->sprite_count; // one load - if (n) { - uint32_t i = 0; - find_sprite: - // 1) position - uint32_t pos = s_ptr->position; // load 1 - if (!pos) { - // 2) pixel from shift bytes - uint32_t sh = s_ptr->shift_hi; // load 2 - uint32_t sl = s_ptr->shift_lo; // load 3 - uint32_t pix = ((sh & 0x80u) >> 6) | ((sl & 0x80u) >> 7); - if (pix) { - // 3) only now fetch metadata - sp_pixel = pix; - sp_palette = s_ptr->palette; // load 4 (only on hit) - sp_prio = s_ptr->priority; // load 5 (only on hit) - sp_zero = (ppu->sprite_zero_in_range != 0u) & (i == 0u); - goto sprite_done; - } - } - // next sprite - ++s_ptr; ++i; - if (i < n) goto find_sprite; - } - } -sprite_done: ; - - const uint32_t bg_index = (bg_palette << 2) + bg_pixel; - const uint32_t sp_index = (sp_palette << 2) + sp_pixel; - const uint32_t selector = ((bg_pixel != 0u) << 1) | (sp_pixel != 0u); - - // Two-way combine with minimal control flow - uint32_t palette_index = 0; - if (selector == 1u) { - palette_index = 0x10u | sp_index; - } else if (selector == 2u) { - palette_index = bg_index; - } else if (selector == 3u) { - const uint32_t use_bg = (sp_prio != 0u); - palette_index = use_bg ? bg_index : (0x10u | sp_index); - if ((ppu->sprite_zero_in_range != 0u) & (sp_zero != 0u) & (x <= 254u)) { - ppu->reg_status |= PPU_STATUS_SPRITE_ZERO_HIT; - } - } - state->pixels[y * 256 + x] = ppu->palette[palette_index]; -} - -#else __attribute__((always_inline, hot, optimize("no-jump-tables", "no-unroll-loops"))) static inline void ppu_render_pixel(struct nes_state * restrict state, uint32_t x, uint32_t y, uint8_t mask_reg) { struct ppu_state *restrict ppu = &state->ppu; @@ -263,7 +176,6 @@ no_sprite: state->pixels[y * 256 + x] = ppu->palette[palette_index]; // NOTE(peter): Add color_emphasis bits (expand palette to 8x). } -#endif __attribute__((noinline, hot, optimize("no-jump-tables", "unroll-loops"))) |