chip-8/src/vcpu.h

#pragma once

#define REG_FLAG 0xF

typedef struct VCPU_State {
  // Program Counter (16 bits but only 12 bits used (4096 memory addresses))
  unsigned short PC;

  // Index register (16 bits but only 12 bits used (4096 memory addresses))
  unsigned short I;

  // Stack register (16 bits)
  unsigned short S;

  // General purpose registers (8 bits each)
  // Note last one often used as a flag register
  unsigned char V[16];

  // Delay timer (8 bits)
  unsigned char DT;

  // Sound timer (8 bits)
  unsigned char ST;

  // Intruction (opcode + decoded fields)
  unsigned short opcode;
  char X;
  char Y;
  char N;
  char NN;
  unsigned short NNN;
} VCPU_State;

void VCPUInit();
void VCPUFetch();
void VCPUDecode();
void VCPUExecute();
void VCPUDump();