Anybody got code for assembly language multiply?

Comments

• Mike Green Posts: 23,101

  2006-08-01 18:17 edited 2006-08-01 18:17

  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.

  pdf

  pdf

  Propeller Guts.pdf

  102K

  Propeller Guts.pdf 102.1K
• Bill Baird Posts: 23

  2006-08-02 00:21 edited 2006-08-02 00:21

  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 Posts: 27

  2006-08-02 04:08 edited 2006-08-02 04:08

  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 Posts: 23

  2006-08-02 23:56 edited 2006-08-02 23:56

  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 Posts: 23,101

  2006-08-03 00:48 edited 2006-08-03 00:48

  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