apps/codecs/libgme/nes_mmc5_apu.h

   1 // NES MMC5 sound chip emulator
   2
   3 // Nes_Snd_Emu 0.2.0-pre
   4 #ifndef NES_MMC5_APU_H
   5 #define NES_MMC5_APU_H
   6
   7 #include "blargg_common.h"
   8 #include "nes_apu.h"
   9
  10 enum { mmc5_regs_addr = 0x5000 };
  11 enum { mmc5_regs_size = 0x16 };
  12 enum { mmc5_osc_count  = 3 };
  13 enum { mmc5_exram_size = 1024 };
  14
  15 struct Nes_Mmc5_Apu {
  16         struct Nes_Apu apu;
  17         unsigned char exram [mmc5_exram_size];
  18 };
  19
  20 static inline void Mmc5_init( struct Nes_Mmc5_Apu* this )
  21 {
  22         Apu_init( &this->apu );
  23 }
  24
  25 static inline void Mmc5_set_output( struct Nes_Mmc5_Apu* this, int i, struct Blip_Buffer* b )
  26 {
  27         // in: square 1, square 2, PCM
  28         // out: square 1, square 2, skipped, skipped, PCM
  29         if ( i > 1 )
  30                 i += 2;
  31         Apu_osc_output( &this->apu, i, b );
  32 }
  33
  34 static inline void Mmc5_write_register( struct Nes_Mmc5_Apu* this, blip_time_t time, unsigned addr, int data )
  35 {
  36         switch ( addr )
  37         {
  38         case 0x5015: // channel enables
  39                 data &= 0x03; // enable the square waves only
  40                 // fall through
  41         case 0x5000: // Square 1
  42         case 0x5002:
  43         case 0x5003:
  44         case 0x5004: // Square 2
  45         case 0x5006:
  46         case 0x5007:
  47         case 0x5011: // DAC
  48                 Apu_write_register( &this->apu, time, addr - 0x1000, data );
  49                 break;
  50
  51         case 0x5010: // some things write to this for some reason
  52                 break;
  53
  54 #ifdef BLARGG_DEBUG_H
  55         default:
  56                         dprintf( "Unmapped MMC5 APU write: $%04X <- $%02X\n", addr, data );
  57 #endif
  58         }
  59 }
  60
  61 #endif