成唯識論述記 4.775

4.775

述曰：謂內六處，即眼根等，八識俱有依皆不過內六處故。若對大乘即通六處，若對小部唯在五內，意處說是等無間故。

The Commentary states: This refers to the six internal bases (āyatana), namely the eye sense-faculty and so forth, because the simultaneous bases of the eight consciousnesses do not exceed the six internal bases. If contrasted with the Mahāyāna, it extends to all six bases; if contrasted with the Hīnayāna schools, it is only within the five internal [bases], because the mind-base (manāyatana) is explained as the equal-and-immediate [condition].