SX Microcontroller Radix Math Method

BCD packed to binary 2 digit to 8 bit

From: Scott Dattalo

        mov     W, >>bcd
        and     W, #01111000b           ;W = tens*8
        mov     temp, W
        clrb    C
        rr      temp                    ;temp = tens*4
        rr      temp                    ;temp = tens*2
        mov     W, bcd-w                ;W = tens*16 + ones - tens*8
                                        ;W = tens*8 + ones
        add     W, temp                 ;W = tens*10 + ones