I wrote:

> To perform the division, I'd take the dividend and multiply it by
> 100, then divide it by the already-multiplied-by-100 divisor using
> an integer 24-bit/16-bit divide routine.
>
> The quotient will be 100 times too large, of course... If you
> don't want to leave it that way, you can divide it by 100 to get
> the real answer.

and myke predko <PICLIST@MITVMA.MIT.EDU> replied:

> Actually, an easier way to do it is to multiply by the fraction of
> 256/65356 and then take off the 256/65356.
>
> ie, for the above example, 4.35 can be represented as:
>
>   256 / 4.35 = 59
>              = 0x03B
>
>    457 * ( 256 / 4.35 ) / 256
>  = 457 * 59 / 256
>  = 0x01C9 * 0x03B / 256                 ;  Putting the Numbers in
>                                         ; Hex = 0x06953 / 0x0100
>
> Division by 256 is pretty easy (just cut off the last two hex
> digits), giving you the result:
>
>    0x069
>  = 105

    Myke:

    Good advice, but your method gives an integer result and a
    remainder modulo 256... Ian needed an integer result and a
    remainder modulo 100.

    If you look at what's required to convert your remainder to the
    form he wanted, I think you'll discover that the method I
    proposed is a little faster.

> Note this algorithm only really works when the divisor is known.

    Which is another reason for the method I suggested... Ian's
    original message implied that both his dividend and his divisor
    were variable.

    -Andy

=== Andrew Warren - fastfwd@ix.netcom.com
=== Fast Forward Engineering - Vista, California
===
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