Hi Peter

This is almost similar. Here I have to find the corresponing column. Can you help me with this one as well?

FindColumn:
mov r0,#4 ;initialize counter
mov a,#0efh ;initialize accumalator
push acc ;and save on stack

TryNextColumn:
pop acc
mov p1,a
rl a
push acc
mov a,P1
orl a,#0f0h
cpl a
jnz ColumnFound
djnz r0,TryNextColumn
pop acc
ret

ColumnFound:
pop acc ;restore stack
mov ,#4 ;number of rows
subb a,r0 ;compute column number
ret

The others are the same, but I just need help with the new parts? Any help would be greatly appreceated!

Regards,
KY