223cc6685e
git-svn-id: svn://svn.compuextreme.de/Viitor/V963/Viitor_cc65@5933 504e572c-2e33-0410-9681-be2bf7408885
86 lines
3.1 KiB
HTML
86 lines
3.1 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
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<HTML>
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<HEAD>
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<META NAME="GENERATOR" CONTENT="LinuxDoc-Tools 0.9.20">
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<TITLE>ca65 Users Guide: Overview</TITLE>
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<LINK HREF="ca65-2.html" REL=next>
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<LINK HREF="ca65.html#toc1" REL=contents>
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</HEAD>
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<BODY>
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<A HREF="ca65-2.html">Next</A>
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Previous
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<A HREF="ca65.html#toc1">Contents</A>
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<HR>
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<H2><A NAME="s1">1.</A> <A HREF="ca65.html#toc1">Overview</A></H2>
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<P>ca65 is a replacement for the ra65 assembler that was part of the cc65 C
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compiler, originally developed by John R. Dunning. I had some problems with
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ra65 and the copyright does not permit some things which I wanted to be
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possible, so I decided to write a completely new assembler/linker/archiver
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suite for the cc65 compiler. ca65 is part of this suite.</P>
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<P>Some parts of the assembler (code generation and some routines for symbol
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table handling) are taken from an older crossassembler named a816 written
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by me a long time ago.</P>
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<H2><A NAME="ss1.1">1.1</A> <A HREF="ca65.html#toc1.1">Design criteria</A>
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</H2>
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<P>Here's a list of the design criteria, that I considered important for the
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development:</P>
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<P>
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<UL>
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<LI> The assembler must support macros. Macros are not essential, but they
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make some things easier, especially when you use the assembler in the
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backend of a compiler.</LI>
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<LI> The assembler must support the newer 65C02 and 65816 CPUs. I have been
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thinking about a 65816 backend for the C compiler, and even my old
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a816 assembler had support for these CPUs, so this wasn't really a
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problem.</LI>
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<LI> The assembler must produce relocatable code. This is necessary for the
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compiler support, and it is more convenient.</LI>
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<LI> Conditional assembly must be supported. This is a must for bigger
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projects written in assembler (like Elite128).</LI>
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<LI> The assembler must support segments, and it must support more than
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three segments (this is the count, most other assemblers support).
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Having more than one code segments helps developing code for systems
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with a divided ROM area (like the C64).</LI>
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<LI> The linker must be able to resolve arbitrary expressions. It should
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be able to get things like
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<BLOCKQUOTE><CODE>
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<PRE>
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.import S1, S2
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.export Special
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Special = 2*S1 + S2/7
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</PRE>
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</CODE></BLOCKQUOTE>
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right.</LI>
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<LI> True lexical nesting for symbols. This is very convenient for larger
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assembly projects.</LI>
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<LI> "Cheap" local symbols without lexical nesting for those quick, late
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night hacks.</LI>
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<LI> I liked the idea of "options" as Anre Fachats .o65 format has it, so I
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introduced the concept into the object file format use by the new cc65
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binutils.</LI>
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<LI> The assembler will be a one pass assembler. There was no real need for
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this decision, but I've written several multipass assemblers, and it
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started to get boring. A one pass assembler needs much more elaborated
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data structures, and because of that it's much more fun:-)</LI>
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<LI> Non-GPLed code that may be used in any project without restrictions or
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fear of "GPL infecting" other code.</LI>
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</UL>
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</P>
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<HR>
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<A HREF="ca65-2.html">Next</A>
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