Palettes, attribute fetch fix (thanks @nzldvd).

src/cartridge.hpp

@@ -1,4 +1,4 @@
-#include "types.hpp"
+#include "common.hpp"
 
 #ifndef CARTRIDGE_HPP
 #define CARTRIDGE_HPP

src/common.hpp

@@ -1,14 +1,16 @@
 #include <cstdint>
 
-#ifndef TYPES_HPP
-#define TYPES_HPP
+#ifndef COMMON_HPP
+#define COMMON_HPP
 
 
+#define NTH_BIT(x, n) (((x) >> (n)) & 1)
+
 /* Integer type shortcuts */
 typedef uint8_t  u8;  typedef int8_t  s8;
 typedef uint16_t u16; typedef int16_t s16;
 typedef uint32_t u32; typedef int32_t s32;
-typedef uint64_t u64; typedef int64_t s64; 
+typedef uint64_t u64; typedef int64_t s64;
 
 
-#endif  // TYPES_HPP
+#endif  // COMMON_HPP

src/cpu.cpp

@@ -93,8 +93,8 @@ template<u8& s, u8& d> void tr()      { upd_nz(d = s); T; }
 template<>             void tr<X,S>() { S = X;         T; }  // TSX, exception.
 
 /* Stack operations */
-void PLP() { T; T; P.reg = (pop() & 0b11001111) | (P.reg & 0b00110000); }
-void PHP() { T; push(P.reg | (1 << 4)); }
+void PLP() { T; T; P.reg = (pop() & 0b11001111) | (P.reg & 0b00110000); }  // Ignore bits 4 and 5.
+void PHP() { T; push(P.reg | (1 << 4));  }  // B flag set.
 void PLA() { T; T; A = pop(); upd_nz(A); }
 void PHA() { T; push(A); }
 
@@ -220,6 +220,7 @@ void reset()
     PC = rd16(0xFFFC);
 }
 
+/* Turn on the CPU */
 void power()
 {
     P.reg = 0x34;
@@ -229,6 +230,7 @@ void power()
     reset();
 }
 
+/* Start the execution */
 void run()
 {
     while (true)

src/cpu.hpp

@@ -1,4 +1,4 @@
-#include "types.hpp"
+#include "common.hpp"
 
 #ifndef CPU_HPP
 #define CPU_HPP
@@ -17,7 +17,7 @@ union Flags
         bool c : 1;      // Carry.
         bool z : 1;      // Zero.
         bool i : 1;      // Interrupt priority.
-        bool d : 1;      // Decimal (useless).
+        bool d : 1;      // Decimal (unused).
         bool b : 1;
         bool unused : 1;
         bool v : 1;      // Overflow.
@@ -25,7 +25,7 @@ union Flags
     };
     u8 reg;
 
-    bool get(u8 i) { return reg & (1 << i); }
+    bool get(u8 i)         { return reg & (1 << i); }
     void set(u8 i, bool v) { reg = v ? (reg | (1 << i)) : (reg & ~(1 << i)); }
 };
 

src/main.cpp

@@ -5,7 +5,7 @@
 int main(int argc, char *argv[])
 {
     Cartridge::load(argv[1]);
-    PPU::init();
+    PPU::power();
     CPU::power();
 
     CPU::run();

src/ppu.cpp

@@ -30,6 +30,16 @@ u8 atShiftL, atShiftH; u16 bgShiftL, bgShiftH;
 int scanline, cycle;
 bool frameOdd;
 
+u32 nes_rgb[] =
+{ 0x7C7C7C, 0x0000FC, 0x0000BC, 0x4428BC, 0x940084, 0xA80020, 0xA81000, 0x881400,
+  0x503000, 0x007800, 0x006800, 0x005800, 0x004058, 0x000000, 0x000000, 0x000000,
+  0xBCBCBC, 0x0078F8, 0x0058F8, 0x6844FC, 0xD800CC, 0xE40058, 0xF83800, 0xE45C10,
+  0xAC7C00, 0x00B800, 0x00A800, 0x00A844, 0x008888, 0x000000, 0x000000, 0x000000,
+  0xF8F8F8, 0x3CBCFC, 0x6888FC, 0x9878F8, 0xF878F8, 0xF85898, 0xF87858, 0xFCA044,
+  0xF8B800, 0xB8F818, 0x58D854, 0x58F898, 0x00E8D8, 0x787878, 0x000000, 0x000000,
+  0xFCFCFC, 0xA4E4FC, 0xB8B8F8, 0xD8B8F8, 0xF8B8F8, 0xF8A4C0, 0xF0D0B0, 0xFCE0A8,
+  0xF8D878, 0xD8F878, 0xB8F8B8, 0xB8F8D8, 0x00FCFC, 0xF8D8F8, 0x000000, 0x000000 };
+
 inline bool rendering() { return mask.bg || mask.spr; }
 
 /* Access PPU memory */
@@ -125,11 +135,13 @@ inline void reload_shift()
 {
     bgShiftL = (bgShiftL & 0xFF00) | bgL;
     bgShiftH = (bgShiftH & 0xFF00) | bgH;
-    atShiftL = (atShiftL << 1)     |  (at & 1);
-    atShiftH = (atShiftH << 1)     | ((at & 2) >> 1);
+    if (!(vAddr.cX % 2))
+    {
+        atShiftL = (atShiftL << 1) |  (at & 1);
+        atShiftH = (atShiftH << 1) | ((at & 2) >> 1);
+    }
 }
 
-#define NTH_BIT(v, i) (((v) >> (i)) & 1)
 void pixel()
 {
     u8 bgBits = (NTH_BIT(bgShiftH, 15 - fX) << 1) |
@@ -139,7 +151,7 @@ void pixel()
     u8 palInd = (atBits << 2) | bgBits;
 
     if (scanline < 240 and cycle >= 1 and cycle <= 256)
-        ((u32*) s->pixels) [scanline * 256 + (cycle - 1)] = rendering() ? (palette[palInd] * 4) << 8 : 0;
+        ((u32*) s->pixels) [scanline * 256 + (cycle - 1)] = rendering() ? nes_rgb[palette[palInd]] : 0;
 
     bgShiftL <<= 1; bgShiftH <<= 1;
 }
@@ -205,7 +217,7 @@ void step()
     scanline = cycle ? scanline : (scanline + 1);
 }
 
-void init()
+void power()
 {
     SDL_Init(SDL_INIT_VIDEO);
     s = SDL_SetVideoMode(256, 240, 32, 0);

src/ppu.hpp

@@ -1,4 +1,4 @@
-#include "types.hpp"
+#include "common.hpp"
 
 #ifndef PPU_HPP
 #define PPU_HPP
@@ -70,7 +70,7 @@ union Addr
     unsigned r : 15;
 };
 
-void init();
+void power();
 void step();
 template <bool write> u8 access(u16 index, u8 v = 0);