850 bytes added, 
11:45, 28 December 2010 = Next line =
This routines calculate the next line from the given address.
== Firmware ==
'''Input:''' HL=Address
'''Output:''' HL=Address of the next line
'''Destroyed:''' AF
<pre>
SCR_NEXT_LINE equ #BC26
call SCR_NEXT_LINE
</pre>
== Without Firmware ==
'''Input:''' HL=Address
'''Output:''' HL=Address of the next line
'''Destroyed:''' AF
<pre>
; Richard Fairhurst 
; October 1997 
; 
;*** Next line down from HL *** 
.nline  ld a,8 
        add h 
        ld h,a 
        and 64 
        ret nz 
        ld bc,16304 
        sbc hl,bc 
        ret
</pre>
= Previous line =
This routines calculate the previous line from the given address.
== Firmware ==
'''Input:''' HL=Address
'''Output:''' HL=Address of the previous line
'''Destroyed:''' AF
<pre>
SCR_PREV_LINE equ #BC29
call SCR_PREV_LINE
</pre>
[[Category:Programming]]