问题
Does anyone know the steps for dividing unsigned binary integers using non-restoring division?
It's hard to find any good sources online.
i.e if A = 101110 and B = 010111
how do we find A divided by B in non-restoring division? What do the registers look like in each step?
Thanks!
回答1:
(My answer is a little late-reply. But I hope it will be useful for future visitors)
Algorithm for Non-restoring division is given in below image :
In this problem, Dividend (A) = 101110, ie 46, and Divisor (B) = 010111, ie 23.
Initialization :
Set Register A = Dividend = 000000
Set Register Q = Dividend = 101110
( So AQ = 000000 101110 , Q0 = LSB of Q = 0 )
Set M = Divisor = 010111, M' = 2's complement of M = 101001
Set Count = 6, since 6 digits operation is being done here.
After this we start the algorithm, which I have shown in a table below :
In table, SHL(AQ) denotes shift left AQ by one position leaving Q0 blank.
Similarly, a square symbol in Q0 position denote, it is to be calculated later
Hope all the steps are clear from the table !!!
回答2:
1) Set the value of register A as 0 (N bits)
2) Set the value of register M as Divisor (N bits)
3) Set the value of register Q as Dividend (N bits)
4) Concatenate A with Q {A,Q}
5) Repeat the following “N” number of times (here N is no. of bits in divisor):
If the sign bit of A equals 0,
shift A and Q combined left by 1 bit and
subtract M from A,
else shift A and Q combined left by 1 bit and add M to A
Now if sign bit of A equals 0, then set Q[0] as 1, else set Q[0] as 0
6) Finally if the sign bit of A equals 1 then add M to A.
7) Assign A as remainder and Q as quotient.
来源：https://stackoverflow.com/questions/12133810/non-restoring-division-algorithm