text: #ifndef _XSM_CONSTANTS_H
  
  #define _XSM_CONSTANTS_H
  
  #include <stdbool.h>
  
  #define XSM_WORD_SIZE 16
  #define XSM_MEMORY_NUMPAGES 128
  #define XSM_PAGE_SIZE 512
  
  #define XSM_REGSIZE XSM_WORD_SIZE
  #define XSM_NUM_REG 33
  
  #define XSM_ILLINSTR -1
  
  #define XSM_SUCCESS 1
  #define XSM_FAILURE 0
  
  #define XSM_INSTRUCTION_SIZE 2
  
  /* Disk states. */
  #define XSM_DISK_IDLE 0
  #define XSM_DISK_BUSY 1
  
  /* Console states. */
  #define XSM_CONSOLE_IDLE 0
  #define XSM_CONSOLE_BUSY 1
  
  #ifndef TRUE
  #define TRUE 1
  #endif
  
  #ifndef FALSE
  #define FALSE 0
  #endif
  
  /* Interrupts */
  #define XSM_INTERRUPT_EXCEPTION 0
  #define XSM_INTERRUPT_TIMER 1
  #define XSM_INTERRUPT_DISK 2
  #define XSM_INTERRUPT_CONSOLE 3
  
  #endif
  