VBCC and SysBase in aos68km target

[Jami]

There is something that I do not understand and that seems weird regarding the SysBase declaration.


I am using :

• VBCC V0.9h patch3 under win10
• aos68km target (which use minimal startup code). This code should set up SysBase, as stated in VBCC 0.9h manual at § 14.5.6 Minimal Startup
• AmigaOS 3.2 NDK3.2R4

• Compiling the code at the end of my post which use SysBase with those parameter works fine :

VC +aos68km -v Librairies.c -o Librairies-inline -I../lib/NDK3.2R4/Include_H

• However, when disabling inline calls, strangely SysBase is undeclared:

VC +aos68km -v Librairies.c -lamiga -o Librairies-no-inline-err -D_NO_INLINE -I../lib/NDK3.2R4/Include_H

->VPrintf("SysBase->SoftVer=%u\n", & (SysBase->SoftVer));
error 82 in line 12 of "Librairies.c": unknown identifier <SysBase>

Defining

_NO_INLINE

prevents SysBase to be set up.
It seems that proto\exec.h of AmigaOS NDK does not define SysBase when

_NO_INLINE

is defined.

• It builds fine if I explicitly list VBCC target headers file before AmigaOS NDK 3.2 headers when calling VC :

 VC +aos68km -v Librairies.c -lamiga -o Librairies-no-inline-ok -D_NO_INLINE -Ibin/targets/m68k-amigaos/include -I../lib/NDK3.2R4/Include_H

Is there another better way to force VC frontend to use VBCC target include file before NDK include files when calling vbccm68k ?
I mean from the command line. (without altering VC config file).


Librairies.c :

#include <proto/exec.h>
#include <proto/dos.h>

struct DosLibrary *DOSBase;

int main()
{
   DOSBase = (struct DosLibrary *) OpenLibrary("dos.library", 0);
  
   if (DOSBase)
   {
       VPrintf("SysBase->SoftVer=%u\n", & (SysBase->SoftVer));
 
       CloseLibrary((struct Library *)DOSBase);
   }

   return 0;
}

[Thomas Richter]

What you observe here is that <proto/exec.h> declares the execbase library entries such that SysBase is taken from address 4, and for that reason does not need SysBase as external symbol. If it is not declared, no harm is done for calling exec functions - except that they are slower than necessary because the code has now to get SysBase from chip RAM (or even worse, has to emulate the access).

[phx]

Hmm... no, I don't think this is what Jami means. You can see that with all NDK3.2 proto-headers. Not only for

proto/exec.h

. For example

proto/graphics.h

:

#ifdef _NO_INLINE

#include <clib/graphics_protos.h>

#else

/****************************************************************************/

#ifndef __NOLIBBASE__

#ifndef GRAPHICS_GFXBASE_H
#include <graphics/gfxbase.h>
#endif /* GRAPHICS_GFXBASE_H */

extern struct GfxBase * GfxBase;
#endif /* __NOLIBBASE__ */

Seems that the official proto headers do not declare the base with

_NO_INLINE

, which is different to the proto headers coming with vbcc. I wouldn't call that a big problem, but maybe I should have insisted in vbcc-compatibility when talking with Olaf Barthel about the new NDK.

NDK3.9 doesn't have that problem, but it also doesn't support

_NO_INLINE

.

Usually the problem shouldn't occur, because you should set up your vbcc config file for aos68k (and aos68km) in a way that the vbcc-headers always have priority over the NDK-headers (the Installer for AmigaOS does that automatically).

To be on the safe side, and also to be compatible with other compilers using NDK3.2, define

__NOLIBBASE__

, and always declare the required library bases yourself.

[Thomas Richter]

All I'm saying is that there are two pragma headers for exec, one taking a6 from location 4 (AbsExecBase), and one from SysBase. If you include the firs one (which is the default), then declaring SysBase is not required, which would explain that no obvious problem is detected when calling functions in exec (and the call being a bit slow), but if the second one is used (sorry, forgot the file name), then a missing definition of SysBase will be detected by the linker.

[Jami]

@Thomas : Thank for your answer. Actually the problem I had was occuring at compiling stage.

Originally Posted by phx

Usually the problem shouldn't occur, because you should set up your vbcc config file for aos68k (and aos68km) in a way that the vbcc-headers always have priority over the NDK-headers (the Installer for AmigaOS does that automatically).

Maybe the "Installing for DOS/Windows" paragraph in manual "vbcc.pdf" could be amended to warn users they should manually include NDK-headers AFTER vbcc-headers (in VC frontend configs or in Makefile or whatever)?

Originally Posted by phx

To be on the safe side, and also to be compatible with other compilers using NDK3.2, define

__NOLIBBASE__

, and always declare the required library bases yourself.

Thank you phx for this tip

[phx]

Originally Posted by Jami

Maybe the "Installing for DOS/Windows" paragraph in manual "vbcc.pdf" could be amended to warn users they should manually include NDK-headers AFTER vbcc-headers

Good hint.
Did that now, before I forget it again. Same for Unix installations.