urgent question about Motorola 56F8323, signals, DSPcore, time

Started by Sik June 2, 2006
Hello, all.

My goal is to use 56F8323 Motorola's Hybrid Controller for filtering a
signal sampled up to 96 KHz with a bandpass.

To implement the digital filter I've to multiply 4 float values and
the results, between every sample.

At this moment I use the uController to get the signal from the
integratedADc and reproduce the sample through a SPI DAc, all at 48Khz
(to not be
ambitious). For test the performance I add between acquisition and
reproduction a stupid code that multiply and add some values.
The code's:
aux=aux+aux; aux=aux*aux; aux=aux*aux; aux=aux*aux;

The compiler translate every instruction to 3 'move.l' and a 'jsr' asm
who spend 18uS on 56F8323@60Mhz (Which's a lot of time because the
period@48Khz is just 20uS long).

Somebody can show me the way to use the 56F8300E core to be able to
calculate the 4 multiplications and the 3 adding float operations within
less than 20uS(48K) or 10uS(96K) ?