shiftm := proc(A,i,j,mstart,mmod,B,l)

read(mergeshift):

for k from 0 to mmod-1 do
   mergeshift(i,4*mmod-1,j,4*mmod+4*(k+mstart) mod 4*mmod,B,l+k*4*mmod,-1,A,4*mmod):
od:

end;