Arithmetic logic operations

1 Performing arithmetic operations
2 Leak control operation
3 Perform a logical computer operation
4 Control of logical operations

Arithmetic operations can be represented as a sequence of elementary operations.

Word transfer
Convert register contents
Shift
Taking the reverse code and the formation of an additional code
When performing arithmetic operations of addition, an error in the result may cause distortions in the whole group of digits

Of the many developed methods for controlling arithmetic operations, the most widely used is the modular control.
The controlled number of arithmetic is divided by q- is the quotient and the remainder.
As a result of the control, the balance of the amount must be equal to the sum of the balance of the items

N = N1 + N2;
Nz / q = quotient + residue r;
Nz / q = quotient + residue r;
Nz / q = quotient + residue r;

r = r1 + r2

Residue formation scheme
Comparison scheme
mistake

Elected as follows

In order for any single error to lead to a violation of the comparability of results by modulating a division operation to determine the remainder, it must be replaced by a simpler operation.
Not in a complicated way.

Equipment implementing modular control should be simpler. And this is possible with a smaller Q value.

q = 2 N -1

n Number of information bits

32 plus 29 equals 61
32/3 equals 10 plus 2
29/3 equals 9 plus 2
601 divided by 3 equals 20 plus 1

2 plus 2 equals 4/30 equals 1 plus 2

If the sum of the residuals is greater or equal, a convolution scheme is applied.

r1 + r2 = r * q

3. The logical operation is performed one-bit and the results of operations are determined by the corresponding bit of the operands. Therefore, it is impossible to find common methods for controlling the results for the logical operation.

The control is as follows

1) repetition is the use of temporal redundancy.
2) simultaneous execution of two different operations with follower comparison of results

AB + (AB) = A + B
AB + (AB) = A + B

For the implementation of control schemes is chosen the equality which includes a controlled operation