lc3.h

#ifndef LC3_H
#define LC3_H

// Memory mapped registers
#define MEMORY_MAX (1<<16)
enum {
  R_R0 = 0,
  R_R1,
  R_R2,
  R_R3,
  R_R4,
  R_R5,
  R_R6,
  R_R7,
  R_PC,   /* program counter register */
  R_COND,  /* condition flags register */
  R_COUNT
};

// Opcodes
enum {
  OP_BR = 0, /* branch */
  OP_ADD,    /* add  */
  OP_LD,     /* load */
  OP_ST,     /* store */
  OP_JSR,    /* jump register */
  OP_AND,    /* bitwise and */
  OP_LDR,    /* load register */
  OP_STR,    /* store register */
  OP_RTI,    /* unused */
  OP_NOT,    /* bitwise not */
  OP_LDI,    /* load indirect */
  OP_STI,    /* store indirect */
  OP_JMP,    /* jump */
  OP_RES,    /* reserved (unused) */
  OP_LEA,    /* load effective address */
  OP_TRAP    /* execute trap */
};

// Condition flags
enum {
  /* These flags indicate the sign of the previous calculation. */
  FL_POS = 1 << 0,
  FL_ZRO = 1 << 1,
  FL_NEG = 1 << 2,
};

// Memory mapped registers
enum {
  MR_KBSR = 0xFE00, /* keyboard status */
  MR_KBDR = 0xFE02  /* keyboard data */
};

// Trap codes
enum {
  TRAP_GETC = 0x20,  /* get character from keyboard, not echoed onto the terminal */
  TRAP_OUT = 0x21,   /* output a character */
  TRAP_PUTS = 0x22,  /* output a word string */
  TRAP_IN = 0x23,  /* get character from keyboard, echoed onto the terminal */
  TRAP_PUTSP = 0x24, /* output a byte string */
  TRAP_HALT = 0x25   /* halt the program */
};

#endif