xref best practice?

[Antiriad_UK]

Hi,

I have a library that is used by different source files that contains various useful functions defined with xdef. How do you tend to add the xref commands? I'm doing this at the moment:

	include "../Framework/IntroLibrary.i"

; Additional external symbols 
	xref	FW_CheckUserQuitSignal_A6
	xref	FW_ClearBuffer_BlitCPU_A6
	xref	FW_ClearBuffer_CPU
	xref	FW_CopyBuffer_CPU
	xref	FW_CPUClearBuffer
	xref	FW_GetFrame
	xref	FW_InitCopperBplPtrs
	xref	FW_InitCopperColsFromPalette
	xref	FW_IsFrameOver
	xref	FW_PreMultCreate_W
	xref	FW_SetLev3Irq
	xref	FW_WaitFrame
	xref	FW_WaitRaster_A6
	xref 	FW_VBlankProxy

	xref	LIB_RGB12_Interpolate_Fast
	xref	LIB_RGB12_Interpolate_Fast_Palette
	xref	LIB_NRV2S_Depack

Which works fine. But it's a pain to have to add all the xrefs you need as that is always different (sometimes I use a couple of routines, sometimes lots).

I could always create a new file like "IntroLibrary_xref.i" and just have all the xrefs in there and include them so I've always got all the functions available and don't have to think about it. But then vasm complains about xrefs to unused functions. You can turn that warning off with -nowarn=62 though.

Had a quick look at the TrapRunner source and this seems to be doing the top version. Only adding the xrefs required in a particular file.

Just curious on what others do

[ross]

Originally Posted by Antiriad_UK

Just curious on what others do

Usually a blob with includes (even nested), so a big mess.

[phx]

Hmm. You saw what I did in Trap Runner, because I like to have an overview which symbols I imported from which modules. This is also the reason I implemented that warning - to make it easy to find unnecessary XREFs.

But there is no problem to XREF any symbol from any object you link with. It doesn't even appear in the object file, when an XREF is unused.

There is also a third option: don't use XREF at all and don't specify the -x option. vasm will automatically import all unknown symbols (other assemblers might not).

[Antiriad_UK]

Hmm, I think I'll just ditch the -x. Less work all around for me

[meynaf]

Originally Posted by Antiriad_UK

Just curious on what others do

I don't use xref. Instead, i abuse of the include directive.

[Antiriad_UK]

I used to as well but in the initial versions of the visual studio code debugger I used it couldn’t handle source level debugging within includes so I got into the habit of separating everything. A bit of a pain at first but much neater now.

[sparhawk]

In vasm, I use the '::' syntax to export symbols. I don't need to use any xref/xdef with this. Or am I missing something?

[hooverphonique]

If I assemble a single assembly file to an object file (no linking) and put an "xdef randomsymbol" statement in the file, I get:

warning 62: imported symbol <randomsymbol> was not referenced

Shouldn't that be an error (and a different message) since I am exporting a non-existing symbol?

If I change xdef to xref, I get the exact same warning, by the way.

vasm command: vasmm68k_mot -quiet -m68000 -Fhunk -showcrit -x -o <object> <source>

[phx]

In fact

xdef

and

xref

refer to the same function in vasm's mot-syntax module. It is best comparable to the

.global

directive of std-syntax (GNU-as).
This means an xref'd/xdef'd symbol stays xref until it is defined, which makes it xdef.

Maybe for better error checking and Devpac compatibility I should add some flags to differentiate between these two?

[hooverphonique]

Originally Posted by phx

Maybe for better error checking and Devpac compatibility I should add some flags to differentiate between these two?

Well, that's up to you - it would be more intuitive to get an error when you export a non-existing symbol, but if not, I think at least you should update the documentation with something similar to what you said above

[phx]

Done (last night).

Try today's daily source snapshot: http://sun.hasenbraten.de/vasm/daily/vasm.tar.gz