David Schleimer

2008-07-26 01:14:01 UTC

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This is because there are two different definitions for XOR:Raw Message

1) 1 iff the number of 1 inputs is 1 (i.e. if the parity of the input is

odd), which is used in 61c

2) 1 iff there is exactly 1 input that is 1, which logism uses

You want the odd parity block in logisim, found under Gates, looks like

a square with 2k+1 on it.

David

Hi,

In our reading we said XOR outputs a 1 when the number of 1's on the input is

odd. This isn't true. It fails if, say, we have a 3 input XOR and all inputs

are 1. This gives us an odd number of 1's but the XOR outputs a 0.

This doesn't match what's in the handouts given as reading and what we

discussed in class.

Kevin

In our reading we said XOR outputs a 1 when the number of 1's on the input is

odd. This isn't true. It fails if, say, we have a 3 input XOR and all inputs

are 1. This gives us an odd number of 1's but the XOR outputs a 0.

This doesn't match what's in the handouts given as reading and what we

discussed in class.

Kevin