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March 3rd, 2013, 07:10 AM   #1
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Signed hexadecimal computation!

Hello, I have questions about signed number representation in computer.
It is about the computation of two hexadecimal number.
Lets say there are two hexadecimal numbers and .
How do I compute this??
What I know is that I have to convert these two hex into binary and the hex that subtract from another, I have to convert that binary into negative binary and add them up.
So will be converted into binary as this.. 8bits
And will be .
If I convert second number into negative by using two's complement, it will be .
If I add them up, I get the result.
is this correct??
I think I heard that I have to throw the carry out... so the result becomes .
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March 3rd, 2013, 12:43 PM   #2
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Re: Signed hexadecimal computation!

Your final result is correct. You can check it by ordinary subtraction, FF - 7F = 80.
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March 3rd, 2013, 01:40 PM   #3
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Re: Signed hexadecimal computation!

so I have throw the carry out right??
Thanks
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March 4th, 2013, 02:59 PM   #4
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Re: Signed hexadecimal computation!

Quote:
Originally Posted by eChung00
so I have throw the carry out right??
Thanks
yes
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