<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix">Am 19.08.2013 13:00, schrieb Mr Paul
Robinson:<br>
</div>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>Based on information and belief, on
Mon, 19 Aug 2013 10:37:43 +0200, Sven Barth
<a class="moz-txt-link-rfc2396E" href="mailto:pascaldragon@googlemail.com"><pascaldragon@googlemail.com></a> wrote to the Free Pascal
list:<br>
<br>
> I don't get what you're trying to say here.<br>
<br>
I mean I spent the better part of a year writing a
cross-reference tool for Free Pascal since the compiler
doesn't include one as they used to do (Mainframe and
minicomputer Cobol, Fortran and Assembler all have built-in
cross-reference as part of the compiler/assembler), then I
had problems implementing a piece of it, so I realized that
I'll come back to it at some time later, and right now I
want to go back and try again with Free Pascal since I now
know what I need to tackle. When I wasn't sure how to ask
for what I knew I needed, I set this request aside to work
on the cross-reference. I had to figure out what was going
on and what I had to do.<br>
</span></div>
</div>
</blockquote>
If you'd now only explain what a cross-reference tool is I might
even understand what you're trying to tell me here...<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> Analyzing what a big-endian
compiler generates won't help you there.<br>
<br>
Possibly, but I have to start somewhere.<br>
<br>
> You need to look into the compiler's code and learn how
it <br>
> does generate code for a specific platform. That has
nothing <br>
> to do with big endian or little endian.<br>
<br>
It does if the compiler generates object files directly (the
way Pascal 8000 did on the 370, UCSD did, and Delphi does).
If the compiler generates assembly language source files
(the way OMSI Pascal did on the PDP-11 and the National
Bureau of Standards Pascal Compiler did), then no,
endianness probably won't matter. But I don't know from
direct examination which FPC does, it's a huge application
and I have no idea what all 100+ units and 264,000 lines of
code do.<br>
<br>
I have to start somewhere and I have to take a guess. There
are three possibilities. (I don't care what FPC does when it
scans the program; that's all magic I probably don't have to
worry about or deal with right now.) (1) The compiler, when
it generates code, generates an intermediate output file
processed by something else (Stanford Pascal, P4, P5, Java
Compilers). (2) The compiler, when it generates code,
generates an assembly language file (or possibly some other
language) for the target that is passed to the Assembler </span><span><span>(OMSI
Pascal for the PDP-11)</span>. (3) The compiler, when it
generates code, generates an actual object file and/or an
executable (Pascal 8000, Turbo Pascal, Microsoft Pascal,
Delphi).</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;">I know not which of these three Free
Pascal does. <br>
</div>
</div>
</blockquote>
FPC uses 2 and 3 depending on the platform and OS. For example for
i386 and x86_64 we have an internal assembler, but for the other
platforms we use an external assembler (mostly the GNU assembler,
but sometimes also others are supported) [Note: the two x86
platforms also support external assemblers]. Also we internal
linkers for some platforms. The first one was for PE based systems
(Windows 32/64 Bit, Windows CE, Native NT) and some months ago we
also gained a ELF linker which currently supports Linux, but still
has a few restrictions (AFAIK). Otherwise we also rely on external
tools (mostly the GNU linker) here. So as a first step you'd choose
the approach of using an external assembler and linker, because
simply calling a third party utility is easier than completely
implementing an internal assembler and linker.<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span></span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> Platform independant stuff is
normally located in <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> the ncg*.pas units and the
platform specific stuff <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> is in the nXY*.pas unit of the
corresponding CPU <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> directory where XY is a short
form of the CPU, e.g. <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> n68kadd.pas for the m68k
add/compare node. Best <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> is you look how other CPUs are
implemented <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> (prefereably the simpler ones
like > MIPS or m68k) <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> and copy that more or less for
the new platform.</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;">My spell checker says you spelled
"independent" and "preferably" worng. :)<br>
</div>
</div>
</blockquote>
And mine says that you spelled "wrong" wrong... can we continue now?<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span></span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>Yeah, and I still have to figure
out what compiler switches to set to enable the existing
compiler to create a cross-compiler for that target that
runs on Windows, and I'm asking for help on that point,
because I figure someone might be able to tell me in 10
words which switches I need. The documentation is rather
sparse on cross-compiling and the code is, well, to say the
least, not very forthcoming.<br>
</span></div>
</div>
</blockquote>
To create a cross compiler there are two possiblities (in both cases
you need to have FPC 2.6.2 installed):<br>
<br>
In a command window (cmd, PowerShell, whatever) go to the directory
where the source code of FPC trunk is located and there execute:<br>
<br>
cd compiler<br>
make all OS_TARGET=linux CPU_TARGET=ppc<br>
<br>
This will generate a compiler which can cross compile to PowerPC
(Note: each compiler for a given platform (i386, x86_64, PowerPC,
etc.) can generate code for each target that is supported there
(e.g. an i386 compiler can generate code for Linux, Win32, WinCE,
Mac OS X, etc.))<br>
<br>
Alternatively you can open the corresponding project file located
inside the "compiler" directory in Lazarus (e.g. pp.lpi for the i386
compiler, ppcx64 for the x86_64 compiler, etc.) and just compile
there. <br>
<br>
To actually use the generated compiler you'll also need to compile
the RTL. For this you should compile the utlity "dummyas" located in
compiler/utils and copy the created executable to e.g. the main
source directory and rename it to "as". Now in the directory "rtl"
you should execute this:<br>
<br>
make all OS_TARGET=linux CPU_TARGET=ppc BINUTILSPREFIX=
CROSSBINDIR=c:\path\to\fpc\source
FPC=c:\path\to\fpc\source\compiler\ppcppc.exe<br>
<br>
Here "c:\path\to\fpc\source" is the path to the directory where your
FPC trunk source is located. If you used Lazarus to compile the
compiler the argument for FPC is different:
"c:\path\to\fpc\source\compiler\powerpc\pp.exe"<br>
<br>
Then you can compile programs using the following (also from the
command line, assuming you are in the source main directory):<br>
<br>
.\compiler\ppcppc.exe -n -Furtl\units\powerpc-linux -FEtestoutput
.\tests\test\tgeneric1.pp<br>
<br>
- assuming there exists a "testoutput" directory in the current
directory which you'd need to create<br>
- if you compiled the compiler using Lazarus the executable is
called ".\compiler\powerpc\pp.exe" instead.<br>
<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
> Adding a new platform to FPC is not cheesecake <br>
<br>
I'm fully aware of this, I'm not stupid and this is not the
first compiler I've worked on, just the largest. I've
written patches to six different Pascal compilers and I've
written two compilers from scratch (not for Pascal), one was
a Fortran IV to Visual Basic translator written in 7,000
lines of VB5, the other was a compiler I needed for a
different purpose. I'm not someone who just fell off the
turnip truck. I know there's (a lot of) work involved. <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>I have to take a guess on where to
start. Given an existing implementation, that I actually get
it to work, I can then figure out what is being done, and
from that, then I can figure out what files are being used
and/or called, and what procedures/methods are invokes. And
that's what I'm asking for help. What do I do to get one of
the existing compilers that generates code for some other
machine to run on Windows and when fed itself, have it
generate an output file of the generated code of itself for
that machine?<br>
<br>
Given that, I can then figure out what to look for.<br>
</span></div>
</div>
</blockquote>
No you can't. As you already said the compiler consists of 100+
units and around 262.000 lines of code plus the code of the RTL. You
can't simply look at that output and transform that somehow for
s370. You need to start small by having the compiler compiler a
simple hello world program or maybe even an empty program (just in
case: the parameters to get the generated assembler output is "-al"
and maybe you'll also need to use "-s" so that the compiler does not
try to call a non existant assembler/linker)<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
> and you should know how the compiler's backend work.
Just looking <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> at the output of a target
won't help you!<br>
<br>
It will a little. Seeing what is generated means I can look
in the source code for where that is generated from, sort of
the way the NSA, if it thinks you're calling a terrorist, it
can search the billions of phone records it secretly seized
to see who else you called! <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>Given the generated output, I can
(presumably) trace it back to whatever program file
generated it and thus figure out what files were used. Going
further, if necessary, I can insert procedure or unit traces
on those files and see what procedures were called in what
order and possibly by whom.<br>
<br>
Given that information, I can figure out what's going on.
I'm just having trouble figuring that out and I wanted any
help someone could point me in where to look.<br>
</span></div>
</div>
</blockquote>
It is easier to simple debug through the compiler. Open the pp.lpi
in Lazarus, write a simple hello world program and set a breakpoint
in compiler\pmodules.pas in the function proc_program at
"main_procinfo.generate_code" (note: you should have no other
procedures/functions in the example as a first step). You can then
step through how the compiler converts the abstract syntax tree to
abstract assembler output. Using the generated assembler to study
the compiler's code generation WILL NOT GET YOU ANY WISER. I can
guarantee you that, because with debugging it is already complicated
enough the first few times.<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
> First step is to get a cross compiler to s370/zSystem
working so <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> that simple programs can be
compiled which you can use to <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> implement the RTL. Only when
enough of the RTL is implemented <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> and the code generator works
good enough then you can try to <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> cross compile the compiler,
but not earlier.<br>
<br>
Right. And I need to figure out what procedures in what
files are being invoked in order to change those so I take
an existing compiler which generates some other target than
Windows, and while that compiler is running under Windows,
turn the switches and flags and defines on, recompile that
compiler so it generates code for the machine it's targeting
(MIPS, PPC, whatever) so that, even though it's running on
Windows, it creates code for the other target machine. Then,
taking that compiler that I know does work and generates PPC
or MIPS code or whatever target its for, change its flags so
that while I ask it to generate S370, it still <br>
generates PPC or MIPS code. Now, then, knowing that, I can
then change its code generator so that now, it will generate
the output code for S370 instead of MIPS or PPC.<br>
<br>
Now, I have a bootstrap compiler that will, on a Windows
box, take a program which is syntactically correct, and when
it runs, it will generate S370 code. Now, at that point I
can recompile the run-time libraries needed to implement the
compiler. Take those generated files over to a real or
simulated 370, and (presumably) assemble them to produce the
run-time library. At that point, I can feed the compiler
into itself, produce its own assembler source, assemble it,
put it on the 370, link it against the previously compiled
library, and if that's right, I should then get a compiler
that runs on the target machine. Then, and at that point, I
can then throw the compiler at itself and it should generate
the exact same output as it did on the Windows box, and at
that point the compiler now is no longer a cross-compiler,
it's a native compiler.<br>
<br>
As I said, I didn't just fall off the turnip truck, I do
know what's involved. But to do that, I first have to get a
cross-compiler for something running on Windows, and I'm
trying to figure out what switches and defines I need!<br>
</span></div>
</div>
</blockquote>
No, you are still thinking to simple. It will take much much time
and running test cases again and again until you've reached the
point that the code generator for s370 is stable enough that it can
successfully compile the compiler's code. Just to name a few: you'll
need to get parameter passing for functions correctly, you need to
correctly retrieve addresses, you need to correctly handle compare
operations, you need to correctly implement loops. The compiler is
only at the end of a very long process which looks very roughly like
this:<br>
- copy an existing code generator (e.g. the aarch64 one as Florian
mentioned) to a new directory s370, adjust the names and search in
the remaining code (including .inc files) for "aarch64" and copy and
adjust the corresponding ifdefs and add corresponding enum values<br>
- test whether the compiler now works by adding a new ppcs370
project where you adjust the paths and the define (instead of
-dAARCH64 it should be -dS370 then)<br>
- start implementing the RTL platform specific functions inside
rtl/s370 based on an existing target (e.g. rtl/mips) again (e.g.
setjump/longjump)<br>
- best try to implement a s370-linux target at first so you don't
need to implement a full RTL as the Linux RTL is already existant<br>
- change the code generator step by step so that it generates
correct code for s370 and test using simple programs maybe even
using a dummy System unit<br>
- try to compile and run testcases located in tests/test/cg which
are especially for testing the code generator<br>
- compile and run more testcases in tests<br>
- only if these testcases run satisfactory you should try to compile
the compiler itself<br>
Please remember that this is only the rough process. It get's more
complicated!<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
>> So how would I get the constants and values added
to <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>>> include the s370 as a
target for FPC? <br>
><br>
> Search the compiler's source for e.g. m68k to see how
other <br>
> platforms are implemented.<br>
<br>
Been there, done that. If you read my comments in the WIKI
on how I was implementing this, I got to the point where the
flags were all inserted, and they did nothing except neither
did the compiler because I didn't have the flags necessary
to invoke what was needed to create an actual working
compiler that could do something, it basically excluded the
target generator!<br>
<br>
So, once I put all the flags in so that I can have something
like -DS370 in the command line recognized as a proposed
target, how can I get that symbol and the associated defines
for the new processor target added to the source base, even
if it's not yet implemented? I basically want to have a
fixed target set so that if someone else works on some other
target there isn't a conflict.</span></div>
</div>
</blockquote>
The conflict can be resolved in the end. There aren't that many new
platforms coming into existance anyway currently...<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span> <br>
I mean, if I didn't want to play nice and make this
available to everyone else, I could just say, "Okay, I need
this done, I can't get the FPC team to accept it for a
branch for the 370, I'll fork the code and make an
incompatible version and now instead of a unified source
tree, there's now an independent branch somewhere else and
people are going to be confused. Not my problem." But I'd
like to be nice and avoid that.<br>
</span></div>
</div>
</blockquote>
You know that you could just ask Florian to give you a branch with
write access? This way it will also be easier to comment on your
changes.<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
So, once I have picked the next set of flags to support a
new processor, that do not change anything for an existing
compile that doesn't invoke or use them, they're just there
as hooks for when they are placed into service, how do I get
them added to the regular source base so I don't end up
creating a fork because what I've changed has not been made
available as part of the rest of the code base?<br>
</span></div>
</div>
</blockquote>
Just work on it in a branch. Even if someone should work at the same
time on a different new platform than these problems can be resolved
once your branch gets merged back to trunk.<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span><br>
>> Second, how do I create a cross-compiler that runs
on Windows, <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>>> for any of the big-endian
processors, so that I can see what it <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>>> has to generate code for
the target machine? Given that, I can <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>>> change the code to either
change the generated object file - if <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>>> it does direct object
files - or the assembly language so it <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>>> generates S370 assembly.<br>
><br>
> No. You should learn how the compiler generates code <br>
<br>
That's what I'm trying to figure out! One module calls
another, which calls another, and so on, and so on, "lather,
rinse, repeat." In the life of some program, the compiler
front end calls one module, which calls another, and on and
on, and at some point it sees the "PROGRAM" or "UNIT"
symbol, or it sees a piece of code indicating that this is a
program that has no program statement, so it will then call
the backend telling it "You need to start compilation of a
program, or a unit" followed by "here's its name," or "it
doesn't have a name."<br>
<br>
There's a place where the scanner hands off to the generator
when it gets a UNIT, VAR, or TYPE or PROGRAM or something
else to indicate a program or unit has started. Or an
executable code for a BEGIN statement. And I want to be
there when it hands off, but I don't know where.<br>
<br>
</span></div>
</div>
</blockquote>
The main part where code generation really kicks in is
tcgprocinfo.generate_code in compiler/psub.pas. Please a breakpoint
there and step through it looking at variables and such using the
debugger. This helps very much though at first it might be
confusing.<br>
<blockquote
cite="mid:1376910018.6646.YahooMailNeo@web162504.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:verdana, helvetica, sans-serif;font-size:12pt">
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>The compiler as it stands is huge,
and any hints on where to look is what I'm asking for. And
what I am asking for is, given the existing code base, what
flags and defines do I set, that, taking the compiler, what
flags do I set to change the default so that on this
compiler, running on Windows, with no flags set in the
source, instead of generating a Windows executable, it
generates an executable for MIPS or PPC?<br>
<br>
Now, then, once that is completed, taking the unmodified
compiler and running it through the new one will generate
that new target even though it's running on Windows. Then, I
can go through the source tree and see what's involved. But
I have to start somewhere and I figure one small question
now could save me weeks of work trying to find it, since,
again, the documentation rather sparse on the question and
is none too open on how to do this.<br>
<br>
I figure someone's 30-second answer, well, you set this
define, and this switch, and point to this directory, and
the compiler will now generate MIPS or PPC code even though
it's running on Windows. And so I compile that version,
once, now, every time I run that version of the compiler it
generates code for that machine instead of Windows. Isolate
the specific source files it uses, which could be anywhere
from 20 to 50 or more, and then I can go through that to
change the target machine. But first, I've got to figure out
how to get FPC to create a consistent different-machine
target, and I figure someone might be able to help.<br>
<br>
> and then implement a new code generator <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> backend for s370, maybe based
on a copy <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> of another platform. Playing
around with <br>
</span></div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
verdana,helvetica,sans-serif; background-color: transparent;
font-style: normal;"><span>> the output won't help you.<br>
<br>
I don't want to play around with the output, I want to play
around with the files that generate that output! And I have
to find out what files are called, and by derivation, what
objects, modules, procedures and functions are being
invoked.<br>
</span><br>
</div>
</div>
</blockquote>
The code generator is implemented inside the platform specific
directories (e.g. compiler/i386, compiler/powerpc, etc.).<br>
<br>
Regards,<br>
Sven<br>
</body>
</html>