StrCpy:
;input: HL = base address of string you wish to copy
;       DE = where you want to copy it to.
;       This program assumes that the string is null-terminated, and that there is enough RAM to hold the entire string.

        ld a,(hl)
        or a        ;compare A to 0.
        ret z
        ld (de),a
        inc hl
        inc de
        jr StrCpy