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Text File  |  1992-11-21  |  1.9 KB  |  34 lines
  1. Newsgroups: comp.sys.m68k
  2. Path: sparky!uunet!noc.near.net!mv!world!squeegee
  3. From: squeegee@world.std.com (Stephen C. Gilardi)
  4. Subject: 64-bit multiply and divide on 68000
  5. Message-ID: <By3nLJ.6H5@world.std.com>
  6. Summary: Need 64-bit division 68000 assembly code, similar to DIVU.L on 68020
  7. Keywords: Assembler 68000 discrete math
  8. Organization: SQ Software via The World Public Access UNIX, Brookline, MA
  9. Date: Sun, 22 Nov 1992 04:10:30 GMT
  10. Lines: 22
  11.  
  12. I need to calculate a linear interpolation rapidly.  The equation is       
  13.                                                                               
  14.   y = x * numer / denom,                                                     
  15.                                                                               
  16. where y, numer, and denom are 32-bit unsigned longs and x is a 16-bit      
  17. unsigned short.                                                               
  18.                                                                     
  19. On the 68020, I can use the built-in "long" multiply and divide instructions. 
  20. However on the 68000 it's more involved.                                    
  21.                                                                            
  22. I found 68000 code in a book to do the 64-bit unsigned multiply.  I'd
  23. like to have the divide in assembly language as well.               
  24.                                                                               
  25. Does anyone have such a routine, or a reference to where I can find one?
  26.  
  27. Thanks,                                                                     
  28. --Steve                                                                     
  29.                                                                              
  30. Stephen C. Gilardi                                                          
  31. SQ Software                                                                
  32. squeegee@world.std.com                                                          
  33.  
  34.