Yes Virginia, there is a Santa Claus.

The Philips XA series is "source compatible" with the '51/52 i.e. you can semiautomatically convert and reassemble yutr '51 assembler code, "C", of course is no problem. Philips selected this route to offer a plethora of new advanced features without losing the heritage.

If you just need 16 bits and pedestrian features you can use the Intel 251 series which actually can run '51 code in "native mode".

Have fun,

Erik