|
From: | michael osullivan |
Subject: | Re: [Pgubook-readers] indexed addressing mode page 15 (revisited) |
Date: | Fri, 7 Oct 2011 17:27:54 +0100 (BST) |
Right i think this post on this list from march1010 answers my question m( please disregard my sentence starting with "I hope i am making sense here.." :) it doesnt make any sense :-) Sorry about that . Anyway here's something that makes sense: ---------------------------------------------------------------------------------------------------
The above example uses: multiplier (7) - 1 (6) so to count the address we have already loaded ( as zero maybe ? ) In the book we have the same but with the index (load 3 to go 4 places ) -------------------------------------------- "For example, if you wanted to access the fourth byte from location 2002, you would load your index register with 3 (remember, we start counting at 0) and set the multiplier to 1 since you are going a byte at a time." The above is the bit from the book that confused me. But i think i have it now. we started off saying add 4 to 2002 = 2006 etc then we are reminded that computers count with a zero and that in actual fact the "N" number of places from ( and including) the loaded address should be counted with a zero ( this is for when we are counting with more than one single byte - so we can access the exact start of a specified record or field within ) ? Hope thats right. I will move on with the rest of the book . Thanks for your help. Mike |
[Prev in Thread] | Current Thread | [Next in Thread] |