text: // System call numbers
  #define SYS_fork          1
  #define SYS_exit          2
  #define SYS_wait          3
  #define SYS_pipe          4
  #define SYS_read          5
  #define SYS_kill          6
  #define SYS_exec          7
  #define SYS_fstat         8
  #define SYS_chdir         9
  #define SYS_dup          10
  #define SYS_getpid       11
  #define SYS_sbrk         12
  #define SYS_sleep        13
  #define SYS_uptime       14
  #define SYS_open         15
  #define SYS_write        16
  #define SYS_mknod        17
  #define SYS_unlink       18
  #define SYS_link         19
  #define SYS_mkdir        20
  #define SYS_close        21
  #define SYS_getpriority  22
  #define SYS_setpriority  23
  