In jsbn, what is the correct function of variable DV?

[Gilberto Mendez]

in jsbn.js file

// (protected) set from integer value x, -DV <= x < DV

function bnpFromInt(x) {
this.t = 1;
this.s = (x < 0) ? -1 : 0;
if (x > 0) this[0] = x;
else if (x < -1) this[0] = x + DV;
else this.t = 0;
}

what is the correct function of variable DV?, i mean, DV -> this.DV? or x.DV? or the function is correct?