simple memory copier

ld h,xx ; High byte of the memory point where data is copied from
ld l,xx ; Low byte of the memory point where data is copied from
ld d,xx ; High byte of the memory point where data is copied to
ld e,xx ; Low byte of the memory point where data is copied to
ld c,xx ; amount of bytes copied
.loop
ld a,(hli)
ld (de),a
inc de
dec c
jr nz, .loop
ret