Difference between revisions of "CSC103: DT's Notes 1"
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Let's take another step which, although it doesn't seem necessary, is absolutely essential. You notice that the last addition generates a carry, and the result is 10. We get two bits. Let's add a leading 0 to the other three resulting bits | Let's take another step which, although it doesn't seem necessary, is absolutely essential. You notice that the last addition generates a carry, and the result is 10. We get two bits. Let's add a leading 0 to the other three resulting bits | ||
| − | 0 0 1 1 | + | 0 0 1 1 <--- a |
+ 0 + 1 + 0 + 1 <--- b | + 0 + 1 + 0 + 1 <--- b | ||
---- ---- ---- ---- | ---- ---- ---- ---- | ||
0 0 0 1 0 1 1 0 <--- S | 0 0 0 1 0 1 1 0 <--- S | ||
| − | + | | | |
| − | + | +---- C | |
Let's call the first bit ''a'', the second bit ''b'', the sum bit ''S'', and the extra bit that we just added ''C'' (for '''c'''arry). Let's show the same information we have in the four above additions into a table, similar to the truth tables we used before where we were discussing boolean algebra. | Let's call the first bit ''a'', the second bit ''b'', the sum bit ''S'', and the extra bit that we just added ''C'' (for '''c'''arry). Let's show the same information we have in the four above additions into a table, similar to the truth tables we used before where we were discussing boolean algebra. | ||
| − | {| | + | {| border="1" cellpadding="10" cellspacing="0" |
! a | ! a | ||
! b | ! b | ||
| Line 602: | Line 602: | ||
| 0 | | 0 | ||
|} | |} | ||
| + | |||
| + | Do you recognize anything? Anything looking familiar? | ||
=References= | =References= | ||
Revision as of 20:07, 31 January 2012
--© D. Thiebaut 08:10, 30 January 2012 (EST)
