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_waitx  	 		22
  #define SYS_set_priority	23
  #define SYS_ps 				24
  #define SYS_return_ticks 	25