1 files changed, 131 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-0.6pre/gme/Nes_Cpu.h b/plugins/gme/game-music-emu-0.6pre/gme/Nes_Cpu.h
new file mode 100644
index 00000000..41b5163c
--- /dev/null
+++ b/plugins/gme/game-music-emu-0.6pre/gme/Nes_Cpu.h
@@ -0,0 +1,131 @@
+// NES CPU emulator
+
+// Game_Music_Emu 0.6-pre
+#ifndef NES_CPU_H
+#define NES_CPU_H
+
+#include "blargg_common.h"
+
+class Nes_Cpu {
+public:
+	typedef BOOST::uint8_t byte;
+	typedef int time_t;
+	typedef int addr_t;
+	enum { future_time = INT_MAX/2 + 1 };
+	
+	// Clears registers and maps all pages to unmapped_page
+	void reset( void const* unmapped_page = NULL );
+	
+	// Maps code memory (memory accessed via the program counter). Start and size
+	// must be multiple of page_size. If mirror_size is non-zero, the first
+	// mirror_size bytes are repeated over the range. mirror_size must be a
+	// multiple of page_size.
+	enum { page_bits = 11 };
+	enum { page_size = 1 << page_bits };
+	void map_code( addr_t start, int size, void const* code, int mirror_size = 0 );
+	
+	// Accesses emulated memory as CPU does
+	byte const* get_code( addr_t ) const;
+	
+	// NES 6502 registers. NOT kept updated during emulation.
+	struct registers_t {
+		BOOST::uint16_t pc;
+		byte a;
+		byte x;
+		byte y;
+		byte flags;
+		byte sp;
+	};
+	registers_t r;
+	
+	// Time of beginning of next instruction to be executed
+	time_t time() const             { return cpu_state->time + cpu_state->base; }
+	void set_time( time_t t )       { cpu_state->time = t - cpu_state->base; }
+	void adjust_time( int delta )   { cpu_state->time += delta; }
+	
+	// Clocks past end (negative if before)
+	int time_past_end() const       { return cpu_state->time; }
+	
+	// Time of next IRQ
+	time_t irq_time() const         { return irq_time_; }
+	void set_irq_time( time_t );
+	
+	// Emulation stops once time >= end_time
+	time_t end_time() const         { return end_time_; }
+	void set_end_time( time_t );
+	
+	// Number of unimplemented instructions encountered and skipped
+	void clear_error_count()        { error_count_ = 0; }
+	unsigned error_count() const    { return error_count_; }
+	void count_error()              { error_count_++; }
+	
+	// Unmapped page should be filled with this
+	enum { halt_opcode = 0x22 };
+	
+	enum { irq_inhibit_mask = 0x04 };
+	
+	// Can read this many bytes past end of a page
+	enum { cpu_padding = 8 };
+
+private:
+	// noncopyable
+	Nes_Cpu( const Nes_Cpu& );
+	Nes_Cpu& operator = ( const Nes_Cpu& );
+
+
+// Implementation
+public:
+	Nes_Cpu() { cpu_state = &cpu_state_; }
+	enum { page_count = 0x10000 >> page_bits };
+	
+	struct cpu_state_t {
+		byte const* code_map [page_count + 1];
+		time_t base;
+		int time;
+	};
+	cpu_state_t* cpu_state; // points to cpu_state_ or a local copy
+	cpu_state_t cpu_state_;
+	time_t irq_time_;
+	time_t end_time_;
+	unsigned error_count_;
+	
+private:
+	void set_code_page( int, void const* );
+	inline void update_end_time( time_t end, time_t irq );
+};
+
+#define NES_CPU_PAGE( addr ) ((unsigned) (addr) >> Nes_Cpu::page_bits)
+
+#if BLARGG_NONPORTABLE
+	#define NES_CPU_OFFSET( addr ) (addr)
+#else
+	#define NES_CPU_OFFSET( addr ) ((addr) & (Nes_Cpu::page_size - 1))
+#endif
+
+inline BOOST::uint8_t const* Nes_Cpu::get_code( addr_t addr ) const
+{
+	return cpu_state_.code_map [NES_CPU_PAGE( addr )] + NES_CPU_OFFSET( addr );
+}
+
+inline void Nes_Cpu::update_end_time( time_t end, time_t irq )
+{
+	if ( end > irq && !(r.flags & irq_inhibit_mask) )
+		end = irq;
+	
+	cpu_state->time += cpu_state->base - end;
+	cpu_state->base = end;
+}
+
+inline void Nes_Cpu::set_irq_time( time_t t )
+{
+	irq_time_ = t;
+	update_end_time( end_time_, t );
+}
+
+inline void Nes_Cpu::set_end_time( time_t t )
+{
+	end_time_ = t;
+	update_end_time( t, irq_time_ );
+}   
+
+#endif