X0 bit 00h
X1 bit 01h
X2 bit 02h
X3 bit 03h
X4 bit 04h
X5 bit 05h
X6 bit 06h
X7 bit 07h
TB bit 08h
 
org 8140h
mov c,x2
cpl c
anl c,/x1
orl c,x0
orl c,x3
mov tb,c
ret
end