machine.h

#define REGS 8
#define MEM_SIZE (1024)

#define ZERO_BIT_FLAGS 1
#define EQUAL_BIT_FLAGS 2
#define LOWER_BIT_FLAGS 3
#define ISSET_BIT(X) (machine.reg[FLAGS] & (1<<(X)))
#define ISSET_ZERO ISSET_BIT(ZERO_BIT_FLAGS)
#define ISSET_EQUAL ISSET_BIT(EQUAL_BIT_FLAGS)
#define ISSET_LOWER ISSET_BIT(LOWER_BIT_FLAGS)

typedef enum { ZERO,
            PC,
            SP,
            R0,
            R1,
            R2,
            R3,
            FLAGS
} Registers ;

typedef enum { IMM, REG, MEM, LABELOP } OperandType ;

struct Operand {
  const char *lab;
  OperandType type; 
  int val;
};

typedef enum {
  NOP,
  MOV,
  LW,
  SW,
  AND,
  PUSH,
  POP,
  PRINT,
  READ,
  ADD,
  SUB,
  MUL,
  DIV,
  CMP,
  JMP,
  JMPE,
  JMPL,
  HLT, 
  LABEL,
  CALL,
  RET,
}Opcode;

struct Instruction {
  Opcode op;
  struct Operand src,dst;
};

struct Machine {
  int reg[REGS];
  int memory[MEM_SIZE+1];
};

extern int count;
extern struct Instruction code[512];