;;array2d
;;gets the address of 2d array
;;Inputs:
;; H: y
;; L: x width
;; B: x
;; DE: Array start
;;Outputs:
;; DE: Array loc address
array2d:
push hl
mlt hl
add hl, de
ld de, 0
ld e, b
ex de, hl
pop hl
ret