10 The Assembler “Trap” Routine

The principal purpose of this chapter is to examine the assembly language code in “m40.s” which is involved in the handling of interrupts and traps.

This code is found between lines 0750 and 0805, and has two entry points, “trap” (0755) and “call” (0766). There are several different and relevant paths through this code and we shall trace some examples of these.