From 6e442f99ce38f724ed8915d7dbe98bfeba5d0a67 Mon Sep 17 00:00:00 2001
From: Themaister <maister@archlinux.us>
Date: Sun, 3 Apr 2011 14:49:43 +0200
Subject: [PATCH] Some small optimizations (seem to work).

---
 nall/algorithm.hpp                            | 12 +++++
 .../ppu-performance/background/background.cpp | 50 ++++++++-----------
 .../ppu-performance/background/background.hpp |  3 +-
 3 files changed, 35 insertions(+), 30 deletions(-)

diff --git a/nall/algorithm.hpp b/nall/algorithm.hpp
index 037f0bb..578fabe 100644
--- a/nall/algorithm.hpp
+++ b/nall/algorithm.hpp
@@ -12,6 +12,18 @@ namespace nall {
   template<typename T, typename U> T max(const T &t, const U &u) {
     return t > u ? t : u;
   }
+
+  template<typename T, typename U>
+  inline unsigned isel_if(int cond, T a, U b) {
+    int mask = (cond | (-cond)) >> 31;
+    return ((unsigned)a & mask) | ((unsigned)b & ~mask);
+  }
+
+  template<typename T, typename U>
+  inline unsigned isel_gez(int cond, T a, U b) {
+    cond >>= 31;
+    return ((unsigned)a & ~cond) | ((unsigned)b & cond);
+  }
 }
 
 #endif
diff --git a/snes/alt/ppu-performance/background/background.cpp b/snes/alt/ppu-performance/background/background.cpp
index 29c70aa..5e450b6 100644
--- a/snes/alt/ppu-performance/background/background.cpp
+++ b/snes/alt/ppu-performance/background/background.cpp
@@ -2,42 +2,38 @@
 
 #include "mode7.cpp"
 
+// Performance critical!!!
 unsigned PPU::Background::get_tile(unsigned hoffset, unsigned voffset) {
   unsigned tile_x = (hoffset & mask_x) >> tile_width;
   unsigned tile_y = (voffset & mask_y) >> tile_height;
 
   unsigned tile_pos = ((tile_y & 0x1f) << 5) + (tile_x & 0x1f);
-  if(tile_y & 0x20) tile_pos += scy;
-  if(tile_x & 0x20) tile_pos += scx;
+
+  tile_pos = isel_if(tile_y & 0x20, tile_pos + scy, tile_pos);
+  tile_pos = isel_if(tile_x & 0x20, tile_pos + scx, tile_pos);
 
   const uint16 tiledata_addr = regs.screen_addr + (tile_pos << 1);
   return (ppu.vram[tiledata_addr + 0] << 0) + (ppu.vram[tiledata_addr + 1] << 8);
 }
 
+// ALU full power
 void PPU::Background::offset_per_tile(unsigned x, unsigned y, unsigned &hoffset, unsigned &voffset) {
-  unsigned opt_x = (x + (hscroll & 7)), hval, vval;
-  if(opt_x >= 8) {
-    hval = self.bg3.get_tile((opt_x - 8) + (self.bg3.regs.hoffset & ~7), self.bg3.regs.voffset + 0);
-    if(self.regs.bgmode != 4)
-    vval = self.bg3.get_tile((opt_x - 8) + (self.bg3.regs.hoffset & ~7), self.bg3.regs.voffset + 8);
+  int opt_x = (x + (hscroll & 7)), hval, vval;
+  int opt_x_cond = opt_x - 8;
+  opt_x_cond = ~(opt_x_cond >> 31);
 
-    if(self.regs.bgmode == 4) {
-      if(hval & opt_valid_bit) {
-        if(!(hval & 0x8000)) {
-          hoffset = opt_x + (hval & ~7);
-        } else {
-          voffset = y + hval;
-        }
-      }
-    } else {
-      if(hval & opt_valid_bit) {
-        hoffset = opt_x + (hval & ~7);
-      }
-      if(vval & opt_valid_bit) {
-        voffset = y + vval;
-      }
-    }
-  }
+  hval = self.bg3.get_tile((opt_x - 8) + (self.bg3.regs.hoffset & ~7), self.bg3.regs.voffset + 0);
+  int bgmode_mask = self.regs.bgmode - 4;
+  vval = isel_if(bgmode_mask, self.bg3.get_tile((opt_x - 8) + (self.bg3.regs.hoffset & ~7), self.bg3.regs.voffset + 8), vval);
+
+  int mask = hval & opt_valid_bit;
+  int hval_mask = hval & 0x8000;
+
+  hoffset = isel_if((mask && ~hval_mask && !bgmode_mask) & opt_x_cond, opt_x + (hval & ~7), hoffset);
+  voffset = isel_if((mask && hval_mask && !bgmode_mask) & opt_x_cond, y + hval, voffset);
+
+  hoffset = isel_if(((hval & opt_valid_bit) && bgmode_mask) & opt_x_cond, opt_x + (hval & ~7), hoffset);
+  voffset = isel_if(((vval & opt_valid_bit) && bgmode_mask) & opt_x_cond, y + vval, voffset);
 }
 
 void PPU::Background::scanline() {
@@ -167,18 +163,14 @@ PPU::Background::Background(PPU &self, unsigned id) : self(self), id(id) {
 
   opt_valid_bit = (id == ID::BG1 ? 0x2000 : id == ID::BG2 ? 0x4000 : 0x0000);
 
-  mosaic_table = new uint16*[16];
   for(unsigned m = 0; m < 16; m++) {
-    mosaic_table[m] = new uint16[4096];
     for(unsigned x = 0; x < 4096; x++) {
-      mosaic_table[m][x] = (x / (m + 1)) * (m + 1);
+        mosaic_table[m][x] = (x / (m + 1)) * (m + 1);
     }
   }
 }
 
 PPU::Background::~Background() {
-  for(unsigned m = 0; m < 16; m++) delete[] mosaic_table[m];
-  delete[] mosaic_table;
 }
 
 #endif
diff --git a/snes/alt/ppu-performance/background/background.hpp b/snes/alt/ppu-performance/background/background.hpp
index 38121a4..1c16d90 100644
--- a/snes/alt/ppu-performance/background/background.hpp
+++ b/snes/alt/ppu-performance/background/background.hpp
@@ -26,7 +26,8 @@ struct Background {
     bool sub_enable;
   } regs;
 
-  uint16 **mosaic_table;
+  //uint16 **mosaic_table;
+  uint16 mosaic_table[16][4096];
 
   const unsigned id;
   unsigned opt_valid_bit;