1 files changed, 116 insertions, 0 deletions

diff --git a/lib/rbcodec/codecs/libgme/z80_cpu.h b/lib/rbcodec/codecs/libgme/z80_cpu.h
new file mode 100644
index 0000000000..341119b6b1
--- /dev/null
+++ b/lib/rbcodec/codecs/libgme/z80_cpu.h
@@ -0,0 +1,116 @@
+// Z80 CPU emulator
+
+// Game_Music_Emu 0.6-pre
+#ifndef Z80_CPU_H
+#define Z80_CPU_H
+
+#include "blargg_source.h"
+#include "blargg_endian.h"
+
+typedef int cpu_time_t;
+typedef int addr_t;
+
+enum { page_bits = 10 };
+enum { page_size = 1 << page_bits };
+enum { page_count = 0x10000 / page_size };
+
+// Can read this far past end of memory
+enum { cpu_padding = 0x100 };
+
+// Can read this many bytes past end of a page
+enum { page_padding = 4 };
+
+#ifdef BLARGG_BIG_ENDIAN
+        struct regs_t { byte b,c, d,e, h,l, flags,a; };
+#else
+        struct regs_t { byte c,b, e,d, l,h, a,flags; };
+#endif
+// BOOST_STATIC_ASSERT( sizeof (regs_t) == 8 );
+        
+struct pairs_t { uint16_t bc, de, hl, fa; };
+        
+// Registers are not updated until run() returns
+struct registers_t {
+        uint16_t pc;
+        uint16_t sp;
+        uint16_t ix;
+        uint16_t iy;
+        union {
+                struct regs_t b; //  b.b, b.c, b.d, b.e, b.h, b.l, b.flags, b.a
+                struct pairs_t w; // w.bc, w.de, w.hl. w.fa
+        };
+        union {
+                struct regs_t b;
+                struct pairs_t w;
+        } alt;
+        byte iff1;
+        byte iff2;
+        byte r;
+        byte i;
+        byte im;
+};
+
+struct cpu_state_t {
+        byte const* read  [page_count + 1];
+        byte      * write [page_count + 1];
+        cpu_time_t base;
+        cpu_time_t time;
+};
+
+struct Z80_Cpu {
+        byte szpc [0x200];
+        cpu_time_t end_time_;
+        
+        struct cpu_state_t* cpu_state; // points to cpu_state_ or a local copy within run()
+        struct cpu_state_t cpu_state_;
+
+        struct registers_t r;
+};
+
+void Z80_init( struct Z80_Cpu* this );
+
+// Clears registers and maps all pages to unmapped
+void Z80_reset( struct Z80_Cpu* this, void* unmapped_write, void const* unmapped_read );
+        
+// TODO: split mapping out of CPU
+        
+// Maps memory. Start and size must be multiple of page_size.
+void Z80_map_mem( struct Z80_Cpu* this, addr_t addr, int size, void* write, void const* read );
+        
+// Time of beginning of next instruction
+static inline cpu_time_t Z80_time( struct Z80_Cpu* this ) { return this->cpu_state->time + this->cpu_state->base; }
+        
+// Alter current time
+static inline void Z80_set_time( struct Z80_Cpu* this, cpu_time_t t ) { this->cpu_state->time = t - this->cpu_state->base; }
+static inline void Z80_adjust_time( struct Z80_Cpu* this, int delta ) { this->cpu_state->time += delta; }
+
+#ifdef BLARGG_NONPORTABLE
+        #define Z80_CPU_OFFSET( addr ) (addr)
+#else
+        #define Z80_CPU_OFFSET( addr ) ((addr) & (page_size - 1))
+#endif
+
+// Maps address to pointer to that byte
+static inline byte* Z80_write( struct Z80_Cpu* this, addr_t addr )
+{
+        return this->cpu_state->write [(unsigned) addr >> page_bits] + Z80_CPU_OFFSET( addr );
+}
+
+static inline byte const* Z80_read( struct Z80_Cpu* this, addr_t addr )
+{
+        return this->cpu_state->read [(unsigned) addr >> page_bits] + Z80_CPU_OFFSET( addr );
+}
+
+static inline void Z80_map_mem_rw( struct Z80_Cpu* this, addr_t addr, int size, void* p )
+{
+        Z80_map_mem( this, addr, size, p, p );
+}
+
+static inline void Z80_set_end_time( struct Z80_Cpu* this, cpu_time_t t )
+{
+        cpu_time_t delta = this->cpu_state->base - t;
+        this->cpu_state->base = t;
+        this->cpu_state->time += delta;
+}
+
+#endif