This is where the main compilation routines are called. This procedure resets many compiler flags and variables, initializes intermediate code, saves source line number, resets compiler switches, and processes statements between begin and end tokes (or asm and end for assembler procedures). After the compilation, module entry and exit code is added. Of course, for …

This is the main program of the compiler. It initializes some data, reads configuration file, processes command line parameters, loads library (reports error if it is not found), initializes module data, checks for the main file, resets compilation timer, compiles the source file and writes compilation status.

This is where the actual compilation starts. Turbo Pascal first clears and prepares some variables and data structures and then compiles the module (unit or program). If program was compiled then compiler checks for indirect references and calls a procedure to link the code and data and to create the executable file.