Predication Story
Lets say that your friend called you after work to tell you that he sent
you a package. There was a special surprise in the package, but he
can't remember if he sent it to your address or to one of your 25 other
friends. You think of how you can get the package. You could:
Guess who he sent it to and send a letter to that one person (like a CISC
or RISC processor would handle a branch)
Send out letters to all the possible friends the package could have been
sent to (like an EPIC processor would do)
Just hope he sent it to you (unlike any computer today)
You, being the smart one, decide to send out letters to all your 25 friends
(to EPIC, 25 possible branch destinations) to tell them to call
you 3 days after they get this letter to tell you if they got your package
or not. Even though this way is the most work, it is the most efficient.
One restriction is you live in an apartment complex, so you have a limited
amount of 25 letters per week (to EPIC, the CPU is working on executing
all the branches so it is occupied and can't do anything else) (you
are lucky that there are only 25 possible friends he could have sent it
to because you can only send 25 letters. This that also means you
cant send any more mail for the week).
If you would have guessed the first choice (like a CISC or RISC processor),
you would have had to wait till that one person calls you, and then if
he/she didn't get it, you have to send and wait again. If that person
did get it, you are either really really good at guessing, or had
lots of luck with you at the time you sent it (CPU guessing the right
branch path). This process would most likely take to long.
The third choice is out of the question because you want this package A.S.A.P.
You send out all your letters and wait about 6 days. Your friends
start calling during this time, leaving you messages (because you don't
answer your phone) that they didn't receive any packages lately and good
luck finding it. Then your best friend calls you. He says "I
got a package today, and I think its yours". He leaves the address
of his new house and you go to his house to pick it up. You go to
his house, get your package, and talk for a little while. When you
get home, you realize that your answering machine is almost full, so you
erase all the messages from the friends who didn't have it (erasing
all wrong branch paths), but keep the message from your best friend
in case you forget his address and just because you were so happy that
he had it (storing the result of the correct branch path in memory).
You then open your package. Its a new computer with a new EPIC processor
(And you know exactly how it works because you read these web pages)!
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