view docs/manual/c13.html @ 396:d0c0fede5021

Update to gcc6809lw patch which may help compilation of some sources Due to persistent random compiler crashes and errors related to "M_REGS", this patch update (4.6.4-2) essentially removes the varius constraints allowing the "soft registers" in most operations. It was causing more problems than it solved and it is not clear that the logic behind those soft registers even makes sense any more. This patch also fixes a bogus comparison related to selecting the right size for a constant. Instead of the excessively clever comparison scheme that was previously in use, the comparisons have been replaced with straight forward comparisions for the top and bottom of the relevant 2's complement ranges.
author William Astle <lost@l-w.ca>
date Mon, 20 Jul 2015 22:32:41 -0600
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>Chapter 1. Introduction</H1
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>The LW tool chain provides utilities for building binaries for MC6809 and
HD6309 CPUs. The tool chain includes a cross-assembler and a cross-linker
which support several styles of output.</P
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>For a long time, I have had an interest in creating an operating system for
the Coco3. I finally started working on that project around the beginning of
2006. I had a number of assemblers I could choose from. Eventually, I settled
on one and started tinkering. After a while, I realized that assembler was not
going to be sufficient due to lack of macros and issues with forward references.
Then I tried another which handled forward references correctly but still did
not support macros. I looked around at other assemblers and they all lacked
one feature or another that I really wanted for creating my operating system.</P
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>The solution seemed clear at that point. I am a fair programmer so I figured
I could write an assembler that would do everything I wanted an assembler to
do. Thus the LWASM probject was born. After more than two years of on and off
work, version 1.0 of LWASM was released in October of 2008.</P
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>As the aforementioned operating system project progressed further, it became
clear that while assembling the whole project through a single file was doable,
it was not practical. When I found myself playing some fancy games with macros
in a bid to simulate sections, I realized I needed a means of assembling
source files separately and linking them later. This spawned a major development
effort to add an object file support to LWASM. It also spawned the LWLINK
project to provide a means to actually link the files.</P
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