; Division by 9
; =============
;
; Ricardo Bittencourt provided us with a fast routine for division by 9.
; It is built for .dsk or Disk ROM routines. It's very fast, but only
; works in the range 0-1440.
;
;
; division by nine
; enter     HL = number from 0 to 1440
; exit      A = HL/9
; destroy   HL,DE
;

DIV9:   INC     HL
        LD      D,H
        LD      E,L
        ADD     HL,HL
        ADD     HL,HL
        ADD     HL,HL
        SBC     HL,DE
        LD      E,0
        LD      D,L
        LD      A,H
        ADD     HL,HL
        ADD     HL,HL
        ADD     HL,DE
        ADC     A,E
        XOR     H
        AND     03FH
        XOR     H
        RLCA
        RLCA
        RET