Can anyone help me regarding

[Manoj Paul]

Hello everybody..

Can anyone help me regarding the following question?

Consider a machine that performs calculations 4 bits at a time. Eight-bit 2's complement numbers can be added by adding the four least significant bits, followed by the four most significant bits. The leftmost bit is used for the sign, as usual. With 8 bits for each number, add -4 and -6, using 4-bit binary 2's complement arithmetic. Did overflow occur?
Did carry occur? Verify your numeric result.

[Manoj Paul]

Ans:

Machine performance: (say) 0011 (i.e. 4 bits at a time)
Eight-bit 2�s complement numbers: (say) 0110 0111

0111 (first)
0110 (second)

�The leftmost bit is used for the sign, as usual� What does it mean?
�With 8 bits for each number, add -4 and -6, using 4-bit binary 2's complement arithmetic�.. What is the procedure?
How can I find out whether overflows occur or not?
And what is a carry?

[David O'Meara]

This still looks like a homework question, and it is still in the wrong forum.