Intermediate, Assembler Language Programming Macro Expansions, and Expression Translation

Writing a program directly in the form of the binary or numerical instruction codes discussed in chapter 6, is difficult and error prone for anything but very simple programs. Generally a programmer would develop a new program using psuedo code representing the meaning of each instruction, which makes it easier to keep track of the behaviour of an evolving program. Even if this psuedo code directly matches the machine code, it introduces a valuable new flexibility that makes the programmer’s task a great deal easier. This results from using variable names instead of value addresses, and where necessary line labels for jump commands before true memory locations have been established. Once a program has been set out in this way it is a relatively automatic process converting it into machine code, even where the task has to be carried out manually.