Automorphism groups of one-point codes from the curves y/sup q/+y=x/sup qr+1/

The automorphism groups are determined for the one-point codes C/sub m/ on the curve over F/sub q/2r defined by y/sup q/+y=x/sup qr+1/, where r is an odd number. This generalizes Xing's theorem (see ibid., vol.41, p.1629-35, Nov. 1995) and extends a result of Wesemeyer (see ibid., vol.44, p.630-43, March 1998)to the case of the above curve.