#define SYS_fork 1
#define SYS_exit 2
#define SYS_wait 3
#define SYS_cons_putc 4
#define SYS_pipe 5
#define SYS_write 6
#define SYS_read 7
#define SYS_close 8
#define SYS_block 9
#define SYS_kill 10
#define SYS_panic 11
#define SYS_cons_puts 12
#define SYS_exec 13
#define SYS_open 14