mirror of
https://github.com/irmen/prog8.git
synced 2024-09-10 09:54:32 +00:00
85 lines
3.7 KiB
ReStructuredText
85 lines
3.7 KiB
ReStructuredText
==============================
|
|
Writing and building a program
|
|
==============================
|
|
|
|
What is a "Program" anyway?
|
|
---------------------------
|
|
|
|
A "complete runnable program" is a compiled, assembled, and linked together single unit.
|
|
It contains all of the program's code and data and has a certain file format that
|
|
allows it to be loaded directly on the target system. Prog8 currently has no built-in
|
|
support for programs that exceed 64 Kb of memory, nor for multi-part loaders.
|
|
|
|
For the Commodore-64, most programs will have a tiny BASIC launcher that does a SYS into the generated machine code.
|
|
This way the user can load it as any other program and simply RUN it to start. (This is a regular ".prg" program).
|
|
Prog8 can create those, but it is also possible to output plain binary programs
|
|
that can be loaded into memory anywhere.
|
|
|
|
|
|
Compiling program code
|
|
----------------------
|
|
|
|
Compilation of program code is done by telling the Prog8 compiler to compile a main source code module file.
|
|
Other modules that this code needs will be loaded and processed via imports from within that file.
|
|
The compiler will link everything together into one output program at the end.
|
|
|
|
The compiler is invoked with the command:
|
|
|
|
``$ ./compile.sh modulefile.p8``
|
|
|
|
For now, it produces intermediate code for the stack-based "StackVM" virtual machine. You can run this code
|
|
with the command:
|
|
|
|
``$ ./stackvm.sh modulefile_stackvm.txt``
|
|
|
|
|
|
.. todo::
|
|
... Real assembler output ...
|
|
It produces an assembly source code file which in turn will (automatically) be passed to
|
|
the `64tass <https://sourceforge.net/projects/tass64/>`_ cross assembler tool
|
|
that assembles it into the final program.
|
|
|
|
|
|
Module source code files
|
|
------------------------
|
|
|
|
A module source file is a text file with the ``.p8`` suffix, containing the program's source code.
|
|
It consists of compilation options and other directives, imports of other modules,
|
|
and source code for one or more code blocks.
|
|
|
|
Prog8 has a couple of *LIBRARY* modules that are defined in special internal files provided by the compiler:
|
|
``c64lib``, ``c64utils``, ``prog8lib``. You should not overwrite these or reuse their names.
|
|
|
|
|
|
.. _debugging:
|
|
|
|
Debugging (with Vice)
|
|
---------------------
|
|
|
|
There's support for using the monitor and debugging capabilities of the rather excellent
|
|
`Vice emulator <http://vice-emu.sourceforge.net/>`_.
|
|
|
|
The ``%breakpoint`` directive (see :ref:`directives`) in the source code instructs the compiler to put
|
|
a *breakpoint* at that position. Some systems use a BRK instruction for this, but
|
|
this will usually halt the machine altogether instead of just suspending execution.
|
|
Prog8 issues a NOP instruction instead and creates a 'virtual' breakpoint at this position.
|
|
All breakpoints are then written to a file called "programname.vice-mon-list",
|
|
which is meant to be used by the Vice emulator.
|
|
It contains a series of commands for Vice's monitor, including source labels and the breakpoint settings.
|
|
If you use the vice autostart feature of the compiler, it will be processed by Vice automatically and immediately.
|
|
If you launch Vice manually, you'll have to use a command line option to load this file:
|
|
|
|
``$ x64 -moncommands programname.vice-mon-list``
|
|
|
|
Vice will then use the label names in memory disassembly, and will activate the breakpoints as well.
|
|
If your running program hits one of the breakpoints, Vice will halt execution and drop you into the monitor.
|
|
|
|
|
|
Troubleshooting
|
|
---------------
|
|
|
|
Getting an assembler error about undefined symbols such as ``not defined 'c64flt'``?
|
|
This happens when your program uses floating point values, and you forgot to import ``c64flt`` library.
|
|
If you use floating points, the compiler needs routines from that library.
|
|
Fix it by adding an ``%import c64flt``.
|