Porting Free Pascal Example

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This is an example of how to port Free Pascal to a new target. The target used here is i386-minix, which is a Unix based microkernel system. Host system is a i386-linux system. For more information about the port see here.

this example is a work in progress

Prerequisites

You'll need the source code of Free Pascal (preferably the most recent version in svn), a SVN client, a working last release of Free Pascal (currently 2.4.0) and a working version of GCC.

It's best to create a new directory where you'll work in.

mkdir $HOME/minix-port
cd $HOME/minix-port

Then either copy an existing Free Pascal working copy on your machine or load a fresh one from the repository. I'll use the second possibility here (for additional help see here):

svn checkout http://svn.freepascal.org/svn/fpc/trunk fpc

Binutils

The first compiler for a new target is always a cross compiler, so we need utilities that allow us to create executables for our target on our host system.

Minix supports the GNU binutils. As the current binutils (2.20) are not "up to date" regarding the output format of Minix we will use the port provided by the Minix distribution.

svn --username anonymous checkout https://gforge.cs.vu.nl/svn/minix/trunk/bigports/binutils-2.16.1 minix-binutils

We also need the source of Minix, cause we need two include files to build the binutils successfully.

svn --username anonymous checkout https://gforge.cs.vu.nl/svn/minix/trunk/src minix

Now copy the needed include files to a directory that is included by the makefiles:

cp minix/include/minix/a.out.h minix-binutils/include/minix-a.out.h
cp minix/include/ansi.h minix-binutils/include/ansi.h

You also need to change the include line in minix-binutils/bfd/i386minix.c from

#include <a.out.h>

to

#include <minix-a.out.h>

Now we can build the binutils:

cd minix-binutils
./configure --host=i686-minix --prefix=../minix-binutils-bin/
make
make install
cd ..

Compiler

Modifications

The following diff shows the changes that were done in already existing files in compiler and utils directories:

Index: compiler/i386/cputarg.pas
===================================================================
--- compiler/i386/cputarg.pas	(Revision 15151)
+++ compiler/i386/cputarg.pas	(Arbeitskopie)
@@ -80,6 +80,9 @@
     {$ifndef NOTARGETNATIVENT}
       ,t_nativent
     {$endif}
+    {$ifndef NOTARGETMINIX}
+      ,t_minix
+    {$endif}
 
 {**************************************
              Assemblers
Index: compiler/systems.pas
===================================================================
--- compiler/systems.pas	(Revision 15151)
+++ compiler/systems.pas	(Arbeitskopie)
@@ -151,6 +151,7 @@
              system_mips_linux,         { 66 }
              system_mipsel_linux,       { 67 }
              system_i386_nativent,      { 68 }
+             system_i386_minix          { 69 }
        );
 
      type
Index: compiler/compiler.pas
===================================================================
--- compiler/compiler.pas	(Revision 15151)
+++ compiler/compiler.pas	(Arbeitskopie)
@@ -113,6 +113,9 @@
 {$ifdef nativent}
   ,i_nativent
 {$endif nativent}
+{$ifdef minix}
+  ,i_minix
+{$endif minix}
   ,globtype;
 
 function Compile(const cmd:string):longint;
Index: utils/fpcm/fpcmake.ini
===================================================================
--- utils/fpcm/fpcmake.ini	(Revision 15151)
+++ utils/fpcm/fpcmake.ini	(Arbeitskopie)
@@ -972,6 +972,14 @@
 SHORTSUFFIX=nativent
 endif
 
+# Minix
+ifeq ($(OS_TARGET),minix)
+BATCHEXT=.sh
+EXEEXT=
+HASSHAREDLIB=0
+SHORTSUFFIX=minix
+endif
+
 else
 # long version for 1.0.x - target specific extensions
 
Index: utils/fpcm/fpcmmain.pp
===================================================================
--- utils/fpcm/fpcmmain.pp	(Revision 15151)
+++ utils/fpcm/fpcmmain.pp	(Arbeitskopie)
@@ -70,7 +70,8 @@
         o_linux,o_go32v2,o_win32,o_os2,o_freebsd,o_beos,o_haiku,o_netbsd,
         o_amiga,o_atari, o_solaris, o_qnx, o_netware, o_openbsd,o_wdosx,
         o_palmos,o_macos,o_darwin,o_emx,o_watcom,o_morphos,o_netwlibc,
-        o_win64,o_wince,o_gba,o_nds,o_embedded,o_symbian,o_nativent
+        o_win64,o_wince,o_gba,o_nds,o_embedded,o_symbian,o_nativent,
+        o_minix
       );
 
       TTargetSet=array[tcpu,tos] of boolean;
@@ -92,14 +93,16 @@
         'linux','go32v2','win32','os2','freebsd','beos','haiku','netbsd',
         'amiga','atari','solaris', 'qnx', 'netware','openbsd','wdosx',
         'palmos','macos','darwin','emx','watcom','morphos','netwlibc',
-        'win64','wince','gba','nds','embedded','symbian','nativent'
+        'win64','wince','gba','nds','embedded','symbian','nativent',
+        'minix'
       );
 
       OSSuffix : array[TOS] of string=(
         '_linux','_go32v2','_win32','_os2','_freebsd','_beos','_haiku','_netbsd',
         '_amiga','_atari','_solaris', '_qnx', '_netware','_openbsd','_wdosx',
         '_palmos','_macos','_darwin','_emx','_watcom','_morphos','_netwlibc',
-        '_win64','_wince','_gba','_nds','_embedded','_symbian','_nativent'
+        '_win64','_wince','_gba','_nds','_embedded','_symbian','_nativent',
+        '_minix'
       );
 
       { This table is kept OS,Cpu because it is easier to maintain (PFV) }
@@ -133,7 +136,8 @@
         { nds    }  ( false, false, false, false, false, true,  false, false, false, false, false, false, false, false),
         { embedded }( true,  true,  true,  true,  true,  true,  true,  true,  true , false, false, false, false, false),
         { symbian } ( true,  false, false, false, false, true,  false, false, false, false, false, false, false, false),
-        { nativent }( true,  false, false, false, false, false, false, false, false, false, false, false, false, false)
+        { nativent }( true,  false, false, false, false, false, false, false, false, false, false, false, false, false),
+        { minix }   ( true,  false, false, false, false, false, false, false, false, false, false, false, false, false)
       );
 
     type

You also need to add the files i_minix.pas and t_minix.pas in compiler/systems directory.

TODO

Compiling

Adding the new RTL

TODO


See also