I didn't find much in the archives for this so I wrote my own....

This routine gets ~27000 multiplies per second in VBA which means on
the real hardware its probably around ~22000 [my gba broke so I can't
test it myself...]

What the code does is a 32x32 multiply then a shift right by 16 bits so
it emulates a multiply for a 16.16 system.

I used a standard double/add method but I think if I could take
advantage of the ARM multiplier somehow that may prove useful. However
two major obstacles, the multiplier is unsigned and it doesn't produce
the upper 32 bits [well at least not in Thumb mode].

The code is at http://tomstdenis.home.dhs.org/mylib.zip

Under /sqrt/sqrt.bin is a precompiled binary for the demo [I used it to
time my sqrt function and then my fmul32].

The source for this function is in GAS assembler code in the files
/lib/amath.s

Anyone else have info on this particular operation? Could someone
please time this on real hardware?

Tom

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