cc -D__PCC__ -I/inc/c -E -o screen.i screen.c
cc -D__PCC__ -I/inc/c -E -o top.i top.c

cc -S -o screen.s screen.i
cc -S -o top.s top.i

as -o screen.o screen.s
as -o top.o top.s

ld -T /inc/_link.ld -o top_ screen.o top.o /lib/libc.a -lgcc