I am using a dsPIC30F3012 (writing in ASM, not C) on a project with very
fast loop execution (<20 uSec in some cases)
and need an effecient 32 bit by 32 bit unsigned divide algorithm.  The
dsPIC30F family has organic 16 by 16 divide
instruction (DIV.U and DIV.UD) and I would like to create a 32 by 32 using
that instruction set.

The traditional 32 by 32 divide using a shift/subtract (restoring)
algorithms is slow (about 400 instruction cycles nominal). It
should be possible to break the 32 by 32 into a set of 16 by 16 operations,
then combine the partials back into a 32 by 32
result, but I lack the knowledge of how to do or drive this.  The dsPIC30F
divide routine is fast (18 cycles, so
any use of itshould have a marked improvement)

I need an unsigned divide, but could live with a signed divide as the
magnitude of numbers I am working with are less than
2^30.  Remainder or lack of is not critical.  If I need it I could derive a
remainder externally to the routine.

--=20
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