Xref:	news2.mv.net comp.os.msdos.djgpp:6533
From:	Pål-Kristian Engstad <engstad AT funcom DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Inline assembly and DMA transfers.
Date:	Mon, 29 Jul 1996 13:23:55 +0200
Organization:	Funcom Oslo AS
Lines:	40
Message-ID:	<31FC9F4B.35F5@funcom.com>
References:	<199607230018 DOT KAA25409 AT gbrmpa DOT gov DOT au>
Reply-To:	engstad AT funcom DOT com
NNTP-Posting-Host:	khazad.funcom.com
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Leath Muller wrote:
> include <stdio.h>
> 
> volatile char *mem_block = NULL;
> volatile int value = 0;
> 
> void fill_block()
> {
[--snip--]
> }
> 

Try this:

static __inline__ void fill_block(char *mem_block, int value)
{
	asm volatile (	"1:	movl %1, (%0)\n"
			"	addl $4, %0\n"
			"	decl %2\n"
			"	cmpl $0, %2\n"
			"	jnz  1b\n"
			: /* Outputs. */
			: /* Inputs. */
			  "r" (mem_block), "r" (value), "r" (50) 
			: /* Modifies. */
			  "cc", 	/* Condition flags. */
			  "memory" 	/* Memory.          */
	);
}

Note that with this scheme, you'll get:
	1. The function inlined, avoiding a precious call.
	2. Register allocation automatic by the compiler.

PKE.
-- 
----------------------------------------------------------------------
| Pål-Kristian Engstad | engstad AT funcom DOT com  | Games programmer, PSX |
| Funcom Oslo AS       | Ph +47 22 42 01 02  | developer & Linux Fan |
----------------------------------------------------------------------

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