Appears to be a rebadged Adhoc Technologies AH101. This is apparently an OEM part with very little discussion in the literature, see http://scripts.online.ru/it/news/engnews/98/11/23_009.htm.

Seems to be a 3-metal ~350nm copper process.

Die label

Mask revision labels

Bond pads

Overview of upper right corner of die, showing power busing and part of the PHY.

Buffer memory and some logic.

Lower left corner. Small memory array (EEPROM maybe?) and logic.

Upper center.

Close up of cell array.