math help needed

Comments

• Bruce Bates Posts: 3,045

  2004-09-01 07:06 edited 2004-09-01 07:06

  Ion -
  
  Thanks to Tracy Allen, here is a tutorial on how to do double precision (32 bit) math with the Basic Stamp:
  http://www.emesystems.com/BS2math6.htm
  
  Regards,
  
  Bruce Bates
• Tracy Allen Posts: 6,667

  2004-09-01 07:55 edited 2004-09-01 07:55

    a0 VAR Word
    a1 VAR Word
    b0 VAR Word
    b1 VAR Word
    c1 VAR Word
    c0  VAR Word
  
    a1 = 9000 : a0 = 0000
    b1 = 7500 : b0 = 0000
    DO
       b0=b0+1
       IF b0 >= 10000 THEN b0 = b0-10000 : b1= b1+1  ' carry
       c0 = a0 - b0
       IF c0.bit15 THEN c0 = c0 + 10000 : c1 = c1-1  ' borrow
       IF c0 = 1567 AND c1=0 THEN DEBUG "wowzer!"
    LOOP
  

  
  
  
  If you let that loop run, it should print "wowzer" on your screen after a wait of about 12 hours!
  
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  Tracy Allen
  www.emesystems.com
• ion Posts: 101

  2004-09-01 10:30 edited 2004-09-01 10:30

  Thank you very much Bruce and Tracy.
  Iwill go to that site and do my home work. You save me a lot of headeche
  Thank again
  ion
• Jon Williams Posts: 6,491

  2004-09-01 14:18 edited 2004-09-01 14:18

  Note of caution: the variables B0 and B1 conflict with internal variable names.
  
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  Jon Williams
  Applications Engineer, Parallax
  Dallas Office
• Tracy Allen Posts: 6,667

  2004-09-01 16:00 edited 2004-09-01 16:00

  Jon is right--We have to keep one another on our toes!--If you try the above program, the compiler v2.1 will come back with a message "Symbol is already defined". Change b0 and b1 to x0 and x1 (or whatever).
  
  The symbols b0 and b1 would point to the same space in the RAM as a0.byte0 and a1.byte1.
  
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  Tracy Allen
  www.emesystems.com