From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Bug in __dpmi_simulate_real_mode_procedure_retf_stack
Date:	Thu, 20 Jan 2000 09:28:00 +0200
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On Wed, 19 Jan 2000, Nigel Pattinson wrote:

> 	/* Set up %esi, %edi to copy data to the PM stack. */
> 	subl	%ecx, %esp
> 	movl	%esp, %edi
> 	movl	ARG3, %esi
> 
> 	/* Copy the data. */
> 	cld
> 	rep
> 	movsw
> 
> Since the size of the parameters (in ecx) is in 16-bit words, it looks
> to me like the line
> 
> 	subl	%ecx, %esp
> 
> only reserves half the required amount of stack space.

But the copy of the data to the stack (see above) *also* uses words:
it copies with "rep movsw".  So it moves ECX words to the stack, and
that's exactly the amount of storage reserved there by subl.

So where exactly is the problem here?

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