Assembly Divide Routine

tekochip

I did a search and didn't come up with one, so here's the one I wrote:

Divide
              mov      x, #27                   'Setup initial conditions
              mov      y, #9                    'for x/y
              mov      divCounter, #32          'Number of bits to shift clears the Z flag
              mov      rem, #0                  'Clear the remainder to start

:Loop
              shl      x, #1 wc, nr             'Just test to see if B31 set
              rcl      rem, #1                  'Shift B31 of x into remainder
              cmpsub   rem, y wc                'Subtract if we can and set flag if we did
              rcl      x, #1                    'Rotate subtraction result into x
              djnz     divCounter, #:Loop       'Rinse and repeat

Mike Green

There's a writeup that includes multiplication, division, and square root routines among other things. Search Parallax for "Propeller Guts".

deSilva

Don't forget to add support for signed operations

It generally makes sense to additionally make a version for 16 bit division (dividing by small numbers is much more common!); if you don't know statically you can check dynamically - it will cut the time needed in halves.. You can extend this idea to 8 bits, as it is just DIVCOUNTER that has to change...