The OCODE machine works by manipulating single-word objects held on a stack, into which there are several pointers, e.g. R(1, 2, 3) STACK 3 adjust the top of stack to leave two cells free for linkage information. LN 1 stack the constant 1. LN 2 stack the constant 2. LN 3 stack the constant 3. LL L6 stack the address of label L6 (the entry to the routine). RTAP 5 enter the procedure adjusting the stack frame pointer by 5 locations. ..... ..... ..... ENTRY 1 L6 'R' entry point for the routine R. SAVE 5 set the top of stack pointer to be 5 locations from the stack frame pointer. ..... RTRN return. 2.4 P-code P-code is the intermediate code used by the PASCAL

compiler [Nori, 1976; Jensen, 1976] and was designed with the aim of porting PASCAL quickly by means of an