The Free On-line Dictionary of Computing (30 December 2018):

INTCODE

    A low-level interpreted language used in
   bootstrapping the BCPL compiler.  The INTCODE machine has six
   control registers and eight functions.  OCODE was used as the
   intermediate language.

   ["INTCODE - An Interpretive Machine Code for BCPL",
   M. Richards, Computer Lab, U Cambridge 1972].

   ["BCPL - The Language and its Compiler", Martin Richards &
   Colin Whitby-Stevens, Cambridge U Press 1979].

   (2014-08-21)