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The compiler is made up of several passes; each pass isimplemented as a separate program. Note that it is notnecessary for the user to invoke each pass individually, asthe C command runs each pass automatically. Note that themachine dependent passes are named differently for each pro-cessorprocessor, for example those with 86 in their name are for the8086 and those with 68K in their name are for the 68000.
The passes are:
;CPP :The pre-processor - handles macros and conditional com-pilationcompilation
;P1 :The syntax and semantic analysis pass. This writesintermediate code for the code generator to read.
;CGEN, CG86 etc.::The code generator - produces assembler code.
;OPTIM, OPT86 etc.:The code improver - may optionally be omitted, reducingcompilation time at a cost of larger, slower code pro-ducedproduced.
;ZAS, AS86 etc.:The assembler - in fact a general purpose macro assem-blerassembler.
;LINK:The link editor - links object files with libraries.
;OBJTOHEX:This utility converts the output of LINK into theappropriate executable file format (e.g. .EXE or .PRGor .HEX). :The passes are invoked in the order given. Each pass reads a file and writes a file for its successor to read. Each intermediate file has a particular format; CPP produces C code without the macro definitions and with uses of macros expanded; P1 writes a file containing a program in an intermediate code; CGEN translates this to assembly code; AS produces object code, a binary format containing code bytes along with relocation and symbol information. LINK accepts object files and libraries of object files and writes another object file; this may be in absolute form or it may preserve relocation information and be input to another LINK command.
There are also other utility programs:
;LIBR:Creates and maintains libraries of object modules
;CREF:Produces cross-reference listings of C or assemblerprograms.