ISLL(x,n) returns the result of logically shifting x to the left by n places, and padding on the right with zeroes.
>>-ISLL(x,n)---------------------------------------------------><
If x is REAL FIXED BIN(p,0) and SIGNED, the result is SIGNED REAL FIXED BIN(r,0) where if p <= M1, r = M1; if p > M1, r = M2.
If x is REAL FIXED BIN(p,0) and UNSIGNED, the result is UNSIGNED REAL FIXED BIN(r+1,0) where if p <= (M1+1), r = (M1+1); if p > (M1+1), r = (M2+1).
Otherwise, x is converted to SIGNED REAL FIXED BIN(p,0) and the result has the same attributes as above.
If n is negative or if n is greater than r, the result is undefined.
isll(+6,1) /* produces 12 */
isll(2147483645,1) /* produces -6 */