[SOLVED] create system unit from scratch

[Key-Real]

I looked at other implementation and the first thing all do is to include systemh.inc, so i do the same:

Code: Pascal  [Select][+][-]

1. unit system;
2. {$MODE FPC}
3. interface
4.  
5. {$I systemh.inc}
6.  
7. implementation
8. end.

but this gives me:



Compiling ./rtl/ps1/system.pp
systemh.inc(23,2) Error: Mode switch "OBJFPC" not allowed here
filerec.inc(33,17) Error: Identifier not found "THandle"
filerec.inc(33,24) Error: Error in type definition
textrec.inc(38,17) Error: Identifier not found "THandle"
textrec.inc(38,24) Error: Error in type definition
systemh.inc(867,17) Error: Identifier not found "TThreadID"
systemh.inc(867,26) Error: Error in type definition
mathh.inc(200,53) Fatal: Syntax error, ")" expected but "=" found
Fatal: Compilation aborted

[Key-Real]

OK, I can't define {$MODE FPC}

[Laksen]

Those missing types are defined a platform specific sysosh.inc

For something like the PS1 maybe take a look at how the embedded platform structures the system unit and the sys*.inc contents

[KodeZwerg]

To compare it with a hospital, you are currently doing a heart transplantation and you just cut off every connection.
So be a good surgeon and put back the missing parts or the heart stay dead.

[Key-Real]

I gonna implement only the minimal requered code in the system unit

pls explain what  type

1)  jmp_buf
2) TExceptAddr
3) TGuid

do and what is minimal implementation of thouse.

I found https://wiki.lazarus.freepascal.org/System_unit

but there is no detailed explanation

[Laksen]

jmp_buf is a record used to store the state of the CPU for the setjmp and longjmp procedures. This functionality is used for exception handling. They are already implemented for MIPS in rtl/mips/setjump*.inc which is included by systemh.inc

TExceptAddr is as the name hints also used for exception handling and implemented in a generic way shared by all the targets in excepth.inc included by systemh.inc
TGuid stores a GUID. The compiler needs to point to it during compilation when GUIDs are needed. Also implemented in a generic manner in objpash.inc included by systemh.inc


The key to implementing a systems unit is to get the proper defines, paths and system specific dummy functionality (usually residese in sys*/tthread/check.inc files) implemented. There's no documentation but you should see how other system units are structured