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Altera_Forum's avatar
Altera_Forum
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14 years ago

LPM_DIVIDE Megafunction

Hey guys, I posted something earlier here about NLMS on an FPGA. So far, I have the LMS working, but I need to perform a fixed point division to perform normalization. My question ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

As usual with fixed point, LPM_DIV doesn't know about it and treats everything as integers.

If both your numerator and denominator are in q4 form (4 fractional bits), then your quotient will be in q0 form (no fractional bits) and your remainder will be in q4 form (4 fractional bits).

More in general, if your numerator is in qX form and your denominator is in qY form, then

- The remainder will be in qX form

- The quotient will be in q(X-Y) form.

Sometimes you can replace division with a multiplication by the inverse, where the inverse is obtained through a look up table.