Question: How to get an nxn binary matrix with some limitations on it

Let A=(a_{i,j}) be an nxn non-singular matrix over GF(2). Assume that we have a positive integer number s and an irreducible polynomial f of degree n over GF(2). 

My question: How to get nxn binary matrices such as A provided that the characteristic polynomial  of these matrices over GF(2) is f and also sum(a_{i,j}) is equal to s with 1<=i<=n and 1<=j<=n.

For example, consider n=8 and s=10 and f= x^8+x^7+x^5+x+1. Then I applied the following Maple code to generate the mentioned matrices. 


 roll := rand(1 .. 64);
 roll1 := rand(1 .. 8); 
 roll2 := rand(9 .. 16);
 roll3 := rand(17 .. 24);
 roll4 := rand(25 .. 32);
 roll5 := rand(33 .. 40);
 roll6 := rand(41 .. 48);
 roll7 := rand(49 .. 56); 
 roll8 := rand(57 .. 64);

u := 1; while u > 0 do 
L := [roll(), roll1(), roll2(), roll3(), roll4(), roll5(), roll6(), roll7(), roll8(), roll()];
if nops({L[]}) = 10 then
A := Matrix(8, 8, 0); s := 0;
for i to 8 do
for j to 8 do 
s := (i-1)*8+j; 
if evalb(`in`(s, L)) then A[i, j] := 1 end if
end do; end do;
if Determinant(A) <> 0 then
if evalb(`in`(sort(`mod`(Factor(CharacteristicPolynomial(A, x)), 2))[x^8+x^7+x^5+x+1]))
then print(A, sort(`mod`(Factor(CharacteristicPolynomial(A, x)), 2))); 
u := 0 end if; end if; 
unassign('A, s, i, j') 
end if; end do; 
unassign('u, i')

with my computer, it takes less than one minute to generate an 8x8 desired non-singular binary matrix as follows

 \begin {array}{cccccccc}
 \end {array} 

I wish I could find a systematic method to find these kind of matrices. 

Thanks for any suggestions 

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