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You have chosen an example that works.
Now consider this: I want to multiply these two 3 bit values through same unsigned multiplier:
111 * 011 = ?
if viewed as unsigned, implies 7 * 3 = 21 [10101 correct]
if viewed as signed, implies -1 * 3 and should give -3
[ but 10101 is wrong now, means -11]
I don't know what you mean by sign extension here but let us try one bit extension:
0 111 * 0 011
7 * 3 = 21 0000 0000 10101 correct
1 111 * 0 011
15* 3 = 45 i.e. 101101 i.e./= -3
Correct ?, Wooooooo
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Let me correct myself, I got a bit flakey with numbers
let us assume the numbers are signed:
111 * 011 (as signed I expect the result to be -1 * 3 = -3
now sign extend according to tricky's trick:
111 111 * 000 011
the verdict:
= 10111101
and means -128 + 61 and /= the expected -3
So what is going on Now?
Honored Contributor
