Hi there,

I was just wondering if anyone knows of a good resource or tutorial regarding computer arithmetic. I'm having trouble grasping the following:

Assume an 8-bit binary number $9C (in hexadecimal format) is stored in a computer. What decimal value does this number represent, assuming that it is:

(i) An unsigned binary integer?
(ii)    A signed two’s complement binary integer?
(iii)   A fixed-point number with the 4 most significant bits for integer and the 4 least significant bits for fraction?

(i)   2^7 + 2^4 + 2^3 +2^2 = 156
(ii)  -2&7 + 2^4 + 2^3 +2^2 = -100
(iii)  int = 2^3+1; frac = 2^-1 + 2^-2

(b) Perform the following calculation in 8-bit two’s complement arithmetic: 

        –64 + 40 = ?

(i) Express each number in the formula as an 8-bit two’s complement number.
(ii)    Perform the calculation and express the result as: (1) an 8-bit two’s complement number, and (2) a hexadecimal number.
(iii)   State the values of the condition code flags N, Z, V, C after the calculation has been performed.

(i)   -64 = 1100 0000, 40 = 0010 1000
(ii) 1100 0000 + 0010 1000 = 1110 1000 = $E8
(iii) NZVC = 1000

I know the answers are provided but if anyone could link me to some resources explaining how this is calculated etc then that would be greatly appreciated.

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Thanks, was looking for something that puts the conversions into simpler terms

How simple are you looking for? Also, have you tried to perform any of the conversions yourself yet?

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