math help needed

ion · 2004-09-01 05:04

hi ,
i have a math problem and need some help to solve it
i have two numbers :
a=90000000 and b=75000000
both of the numbers are divided in high· and low like
a= 9000 high and 0000 low. the same for b.
i have also a limit level like c=1567
b it will increment if an event happen
i would like to monitor b in a such way that when a-b=c to get an output or alarm or a conditional branch to do something.
thanks
ion
·

Bruce Bates · 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 · 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 · 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 · 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 · 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

math help needed

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