some optimization tests that didn't pan out

2 files changed, 2 insertions, 90 deletions

diff --git a/mknes.c b/mknes.c
index 244a032..e3e9ffd 100644
--- a/mknes.c
+++ b/mknes.c
@@ -58,8 +58,8 @@ static void audio_callback(int16_t *data, size_t frames) { }
 #ifdef BENCHMARK
 // Embed the ROM for benchmarking to eliminate file I/O overhead
 // Uncomment the ROM you want to benchmark:
-INCBIN_BYTES(benchmark_rom, "data/Life Force (USA).nes");
-// INCBIN_BYTES(benchmark_rom, "data/0000/Super Mario Bros. (World) (HVC-SM).nes");
+// INCBIN_BYTES(benchmark_rom, "data/Life Force (USA).nes");
+INCBIN_BYTES(benchmark_rom, "data/0000/Super Mario Bros. (World) (HVC-SM).nes");
 // INCBIN_BYTES(benchmark_rom, "data/0003/Gradius (USA).nes");
 #endif
 
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")))