[Libre-soc-bugs] [Bug 555] encode a dotproduct in a single instruction

[bugzilla-daemon at libre-soc.org]

https://bugs.libre-soc.org/show_bug.cgi?id=555

Jacob Lifshay <programmerjake at gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |programmerjake at gmail.com

--- Comment #8 from Jacob Lifshay <programmerjake at gmail.com> ---
(In reply to Luke Kenneth Casson Leighton from comment #3)
> jacob notes: fma reduction would be a polynomial reduction but it would be a
> Bad Idea (tm) to implement in hardware

*could* be a polynomial reduction:
v = a
v = x * v + b
v = x * v + c
v = x * v + d

produces:
v == d + x * c + x^2 * b + x^3 * a


having fma reduction be a dot product is also valid, easier to implement in
hardware, and more useful:
v = a
v = b * c + v
v = d * e + v
v = f * g + v

v == a + dot(<b, d, f>, <c, e, g>)

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