The description of the _lrol_ function in the C51 User's Guide 03.2000 says, "This routine is implemented as an intrinsic function. The code required is included in-line rather than being called." And yet, in my assembler, I see:
034B E0 MOVX A,@DPTR 034C F8 MOV R0,A 034D 120000 E LCALL ?C?LROL