Anybody got code for assembly language multiply?

Bill Baird

Anybody got a piece of code handy for assembly language multiply?

Mike Green

There's a document that was posted some time ago called "Propellor Guts" that includes a discussion of multiplication and division including sample routines. I've attached a copy since I don't have the link handy.

Bill Baird

Woah - Thank You. There is a wealth of good stuff for assembly coding in here that I didn't find in the newly released manual.

Direct Digital Labs

And don't forget this page.

http://www.sxlist.com/cgi-bin/constdivmul.exe?cpu=sx

It shows how some functions are done on the SX using shifs and adds. You can then make you own code for the Propellor..

-Dan

Post Edited (Direct Digital Labs) : 8/2/2006 4:14:24 AM GMT

Bill Baird

Thanks - I have used the SX assembly code for multiply - I just wanted to see if there was a slick way to do it in propellor assembly.

Mike Green

Along the line of multiplication and division, here's a 32 bit divide that yields a 32 bit quotient and remainder.

'' 32 bit unsigned division yielding quotient and remainder

divide                  mov     temp,#32                ' Divide a 32 bit unsigned dividend
                          mov     remainder,#0            '  by a 32 bit unsigned divisor to
:loop                   shl     dividend,#1        wc   '  get a 32 bit unsigned quotient
                          rcl     remainder,#1            '  and a 32 bit unsigned remainder
                          cmpsub  remainder,divisor  wc,wr
                          rcl     quotient,#1
                          djnz    temp,#:loop
divide_ret           ret

temp                  long    0
dividend             long    0
remainder          long    0
divisor                long    0
quotient             long    0