Shamusworld >> Repos - apple2/blob - src/vay8910.h

   1 //
   2 // Virtual AY-3-8910 Emulator
   3 //
   4 // by James Hammons
   5 // (C) 2018 Underground Software
   6 //
   7
   8 #ifndef VAY8910_H
   9 #define VAY8910_H
  10
  11 #include <stdint.h>
  12
  13 struct VAY_3_8910
  14 {
  15         // User visible registers
  16         uint16_t period[3];             // Channel A-C period
  17         int16_t volume[3];              // Channel A-C volume (non-envelope mode)
  18         bool envEnable[3];              // Channel A-C envelope enable
  19         bool toneEnable[3];             // Channel A-C tone enable
  20         bool noiseEnable[3];    // Channel A-C noise enable
  21         uint16_t noisePeriod;   // Noise period (5 bits * 16)
  22         uint32_t envPeriod;             // Envelope period (16 bits * 256)
  23         bool envAttack;                 // Envelope Attack bit
  24         bool envAlternate;              // Envelope Alternate bit
  25         bool envHold;                   // Envelope Hold bit
  26         // Internal registers
  27         uint16_t count[3];              // Channel A-C current count
  28         bool state[3];                  // Channel A-C current state
  29         uint16_t noiseCount;    // Noise current count
  30         bool noiseState;                // Noise state
  31         uint32_t envCount[3];   // Envelope current count
  32         int16_t envDirection[3];// Envelope direction (rising, 0, or falling)
  33         uint32_t prng;                  // Psuedo RNG (17 bits)
  34         uint8_t regLatch;               // Register latch (written by 6522VIA)
  35         uint8_t data;                   // Data lines (written by 6522VIA)
  36         uint8_t id;                             // Chip ID (optional)
  37
  38         VAY_3_8910();
  39         void Reset(void);
  40         void WriteControl(uint8_t);
  41         void WriteData(uint8_t);
  42         void SetRegister(void);
  43         uint16_t GetSample(void);
  44
  45         // Class variables
  46
  47         // Maximum volume that can be generated by one voice
  48         static float maxVolume;
  49         // Normalized volumes (zero to one) for AY-3-8910 output, in 16 steps
  50         static float normalizedVolume[16];
  51 };
  52
  53 // Exported variables
  54 extern bool logAYInternal;
  55
  56 #endif  // VAY8910_H
  57