BC_Div_DE (Speed Tweak, +8 bytes -461cc avg).

;===============================================================
BC_Div_DE:
;===============================================================
;Performs BC/DE
;Speed:   1150+6b cycles when DE<256 (1/256 of the time)
;         688+6b cycles when DE>=256 (255/256 of the time)
;         Avg = 716.88671875cc
;Size:    35 bytes
;Inputs:
;     BC is the numerator
;     DE is the denominator
;Outputs:
;     BC is the quotient
;     HL is the remainder
;     DE is not changed
;     A is 0
;     z flag is set
;     c flag is reset
;===============================================================
    ld hl,0
    ld a,b
    ld b,16
    inc d
    dec d
    jr z,loop
    ld l,a
    ld a,c
    ld b,8
loop:
    rl c
    rla
    adc hl,hl
    sbc hl,de
    jr nc,$+3
    add hl,de
    djnz loop
    rl c
    rla
    cpl
    ld b,a
    ld a,c
    cpl
    ld c,a
    ret