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December 6th, 2007, 02:48 PM  #1 
Joined: Dec 2007 Posts: 187  Arithmetic/Logic Unit
In an average computer, where is the arithmetic/logic unit located at? Isn't it part of CPU? Also, doesn't the programming software uses this arithmetic/logic unit to calculate most of the mathematical calculations?

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December 6th, 2007, 06:19 PM  #2  
Joined: Dec 2007 Posts: 138  Re: Arithmetic/Logic Unit Quote:
You may want to check the wikipedia article... Wikipedia is a nerd's best friend.  
December 7th, 2007, 05:02 AM  #3 
Joined: Dec 2007 Posts: 232  Re: Arithmetic/Logic Unit
They used to be completely separate from the CPU proper (the 80286 and 80287 were that way, I think) but on the same die. But as you can imagine, the speed of light coupled with modern clock speeds essentially requires that the CPU be touching.

December 15th, 2007, 09:19 PM  #4 
Joined: Dec 2007 Posts: 2  Re: Arithmetic/Logic Unit
Hmmm, if I remember my history correctly (which I probably don't,) the Pentium was the first cpu to incorporate an ondie ALU... or maybe it was the first to incorporate two ALU's. It was probably the latter.

December 19th, 2007, 10:26 AM  #5 
Joined: Dec 2007 Posts: 232  Re: Arithmetic/Logic Unit
Who knows, I don't remember all that well either. Maybe the Pentium was the first that shipped standard with that feature  the 80287 was optional, I believe.

February 4th, 2009, 04:48 AM  #6 
Joined: Dec 2008 Posts: 32 
Yes it is a part of CPU. Yes, programming software uses this arithmetic/logic unit to calculate most of the mathematical calculations.

April 30th, 2010, 02:08 PM  #7 
Joined: Apr 2010 Posts: 96  Re: Arithmetic/Logic Unit
Microcontrollers contain an ALU and a CPU the CPU deals with shifting of data while the ALU does all the math, logic and comparissons...the cpu merely moves the data into the registers allowing the ALU access....if you wish to learn more perhaps you should read my thread on the fetchexecute cycle and if you would like a thread dedicated to how the CPU is set out, the architecture of it internally then pm me and when I have time I would be much obliged. 
August 17th, 2010, 07:16 PM  #8 
Joined: Aug 2010 Posts: 1  Re: Arithmetic/Logic Unit
Hmm, old topic, but I'll toss in my 2 cents worth anyway. I think there is some confusion between ALU (arithmetic logic unit) and FPP (floating point processor). The 80287 was an FPP, not an ALU. Back when dinosaurs roamed the earth, and I took my first computer class, The ALU was considered to be part of the CPU, not separate from it. It was the part that did low level things like integer add, subtract, shift, rotate, AND, OR, Complement, etc. The other primary part of the CPU was the program control which handled the program counter, fetching instructions and reading/writing data to/from memory. Of course, over the years, definitions tend to shift a bit. 