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95 lines
4.3 KiB
Plaintext
95 lines
4.3 KiB
Plaintext
<preface>
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<title>Preface</title>
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<para>
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The Ophis project started on a lark back in 2001. My graduate
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studies required me to learn Perl and Python, and I'd been playing
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around with Commodore 64 emulators in my spare time, so I decided
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to learn both languages by writing a simple cross-assembler for
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the 6502 chip the C-64 used in both.
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</para>
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<para>
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The Perl one—uncreatively
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dubbed <quote>Perl65</quote>—was quickly abandoned, but the
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Python one saw more work. When it came time to name it, one of the
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things I had been hoping to do with the assembler was to produce
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working Apple II programs. <quote>Ophis</quote> is Greek
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for <quote>snake</quote>, and a number of traditions also use it
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as the actual <emphasis>name</emphasis> of the serpent in the
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Garden of Eden. So, Pythons, snakes, and stories involving really
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old Apples all combined to name the
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assembler.<footnote><para>Ironically, cross-platform development
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for the Apple II is extremely difficult, and while Ophis has been
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very successfully used to develop code for the Commodore 64,
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Nintendo Entertainment System, and Atari 2600, it has yet to
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actually be deployed on any of the Apples which inspired its
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name.</para></footnote>
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</para>
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<para>
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Ophis slowly grew in scope and power over the years, and by 2005
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was a very powerful, flexible macro assembler that saw more use
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than I'd expect. In 2007 Ophis 1.0 was formally released.
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However, Ophis was written for Python 2.1 and this became more and
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more untenable as time has gone by. As I started receiving patches
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for parts of Ophis, and as I used it for some projects of my own,
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it became clear that Ophis needed to be modernized and to become
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better able to interoperate with other toolchains. It was this
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process that led to Ophis 2.
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</para>
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<para>
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This is an updated edition of <emphasis>Programming With
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Ophis</emphasis>, including documentation for all new features
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introduced and expanding the examples to include simple
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demonstration programs for platforms besides the Commodore 64. It
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also includes updated versions of the <emphasis>To HLL and
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Back</emphasis> essays I wrote using Ophis and Perl65 as example
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languages.
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</para>
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<section>
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<title>Getting a copy of Ophis</title>
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<para>
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As of this writing, the Ophis assembler is hosted at Github. The
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latest downloads and documentation will be available
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at <ulink url="http://github.com/michaelcmartin/Ophis"></ulink>. If
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this is out-of-date, a Web search on <quote>Ophis 6502
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assembler</quote> (without the quotation marks) should yield its
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page.
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</para>
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<para>
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Ophis is written entirely in Python and packaged using the
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distutils. The default installation script on Unix and Mac OS X
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systems should put the files where they need to go. If you are
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running it locally, you will need to install
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the <literal>Ophis</literal> package somewhere in your Python
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package path, and then put the <command>ophis</command> script
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somewhere in your path.
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</para>
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<para>
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For Windows users, a prepackaged system made
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with <command>py2exe</command> is also available. The default
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Windows installer will use this. In this case, all you need to
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do is have <command>ophis.exe</command> in your path.
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</para>
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</section>
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<section>
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<title>About the examples</title>
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<para>
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Versions of the examples in this book are available from the Ophis site. Windows users will find them packaged with the distribution; all other users can get them as a separate download or pull them directly from github.
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</para>
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<para>
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The code in this book is available in
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the <literal>examples/</literal> subdirectory, while extra
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examples will be in subdirectories of their own with brief
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descriptions.
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</para>
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<para>
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Most examples will require use of <emphasis>platform
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headers</emphasis>—standardized header files that set
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useful constants for the target system and, if needed, contain
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small programs to allow the program to be loaded and run. These
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are stored in the <literal>platform/</literal> subdirectory.
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</para>
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</section>
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</preface>
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