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
SCR_NEXT_LINE equ #BC26 call SCR_NEXT_LINE
Without Firmware
Input: HL=Address
Output: HL=Address of the next line
Destroyed: AF,BC
; Richard Fairhurst
; October 1997
;
;*** Next line down from HL ***
.nline ld a,8
add h
ld h,a
ret nc
ld bc,#c050
add hl,bc
ret
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
SCR_PREV_LINE equ #BC29 call SCR_PREV_LINE