594
Subj : Re: An order or linking bug
To   : borland.public.cpp.borlandcpp
From : Bob Gonder
Date : Thu Dec 09 2004 08:08 pm

"David Morris" <DONTSPAMdlmorris-ATDONTSPAM-netwiz-com-au
-@don't.use.this.bit> wrote:

>I am using TASM.  I am pushing the DS, and reloading loading it (to be sure, to
>be sure), so I am pretty sure that the ISR has the correct segment.

What I am suggesting is that the pointers be stored as far pointers:
	char far * InPointer;
	char far * OutPointer;

	asm{	push	es;
		push ds;
		lds	si,InPointer;
		les	di,OutPointer;
		movsb;
		mov	word ptr InPointer,si;
		mov	word ptr OutPointer,di;
		pop	ds;
		pop	es;
	};


>  The ES
>register is not used by the ISR as far as I can tell (unless its use is masked
>by IDEAL mode?).

It's not "masked".  Instructions such as movsb and stosb always use
es:di

>The buffer is only 8K.  I placed some maker characters around the pointers
>(both behind and ahead), and they were never touched. 

When you were having this problem, did you check what the actual
buffer address was?

>  I thought the whole
>DGROUP can only be 64k in the large memory model.   Do the hardware 64k
>boundaries count?

Large model allows very much data.
In large model, all pointers should be far.

You never posted your ISR code.
If you want to post it over in borland.public.tasm, I'll take a look
at it and see what can go wrong.

.

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