Source : Free On-Line Dictionary of Computing

U-Code
     
        Universal Pascal Code.  Intermediate language, a
        generalisation of P-code for easier optimisation.  Developed
        originally for the Los Alamos Cray-1 and the Lawrence
        Livermore S-1.  A refined version currently used by MIPS
        compilers is descended from one at Stanford U.  "Machine
        Independent Pascal Code Optimisation", D.R. Perkins et al,
        SIGPLAN Notices 14(8): 201-201 (1979).  "A Transporter's Guide
        to the Stanford U-Code Compiler System", P. Nye et al, TR CSL
        Stanford U, June 1983.  (See HPcode).