RISC-51? That would put it in the same class as the other 8051-based SoCs we know of (ALi M566x/M7101, Nexia/ECT NX585x/SkylarkA/SkylarkII)
But the datasheet wording is definitely Actions-inspired, here is the intro on the 209X datasheet:
...also, the clock speed (24MHz to 60MHz) is around the same as for the Actions SoCs.