ADSP2101 Double Precision

I have part of a filter below and would like to convert this to double precision.. Any help???

startDemph:

>

> CNTR = ar; /* load counter */

>

> DO to_lrs UNTIL CE; /* loop until count expires, end

> of buffer */

>

>

> SR0 = dm(I7,M6); /* load sample from buffer */

> MX1 = dm(l_last_in); /* previous samples */

> AR = dm(l_last_out);

> MY0 = dm(de_a0); /* load 1st coefficient */

> MR = MX0 * MY0 (SS);

> MY0 = dm(de_a1); /* load 2nd coefficient */

> MR = MR + MX1 * MY0 (SS);

> MY0 = dm(de_b1); /* load 3rd coefficient */

> MR = MR + AR * MY0 (SS);

> MR = MR (RND);

> IF MV SAT MR;

> dm(l_last_out) = MR1;

> dm(l_last_in) = MX0;

> dm(I7,M7) = MR1; /* store new filtered sample

> */

>

> to_lrs:

processors and dsp

adsp-2101

ADSP-21xx Fixed-Point DSPs