Lourens Veen wrote:
On Tuesday 01 February 2005 20:03, Timothy Miller wrote:
Therein lies a problem. Since the reciprocal isn't precise (we use
only 10 mantissa bits when computing it)
Hmm, I thought we had 18 bits of precision readily available. Is this a
consequence of using linear interpolation for the divide?
I was also under the impression that 10 mantissa bits were used for the
LUT, and the other bits were used for linear interpolation between two 18
bit values from the LUT.
I wasn't even going to bother with the interpolation. The reason is
that we have a limited number of RAM blocks and they're dual ported. If
we're going to properly compute every fragment (not estimate odd ones),
then we have to look up two reciprocals every cycle.
Erm, look up four reciprocals right? Two to interpolate between for the even
fragment, and two for the odd fragment? And the RAM is dual ported, so you're
two ports short?
Exactly, which would necessitate the use of two RAM blocks.
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