Xref: news2.mv.net comp.os.msdos.djgpp:2091
From: korpela AT islay DOT ssl DOT berkeley DOT edu (Eric J. Korpela)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Is this ASM ok?
Date: 22 Mar 1996 18:41:13 GMT
Organization: Cal Berkeley-- Space Sciences Lab
Lines: 26
Message-ID: <4ius89$76n@agate.berkeley.edu>
References: <3150B8B2 DOT 8B2 AT jeffnet DOT org> <4ishog$obf AT mack DOT rt66 DOT com>
NNTP-Posting-Host: islay.ssl.berkeley.edu
To: djgpp AT delorie DOT com
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In article <4ishog$obf AT mack DOT rt66 DOT com>,
Brennan "Mr. Wacko" Underwood <brennan AT mack DOT rt66 DOT com> wrote:
>asm(
>  "loopf:\n\t"
>  "movb %%dh, (%%edi)\n\t"	/* write integer portion of color - U1 */
>  "addl %%ebx, %%edx\n\t"       /* Add colstep to col             - V1 */
>  "incl %%edi\n\t"		/* increment edi                  - U2 */
>  "decl %ecx\n\t"		/* decrement count                - V2 */
>  "jnz loopf"     	        /* If ecx not zero goto loop      - U3 */
>  : : "D" (tscreen), "d" (tcol1), "b" (tcolstep), "c" (tlength)/*loaded regs*/
>  : "%edi", "%ebx", "%ecx", "%edx"); /* clobbered regs */

I think there is a problem with your clobbered register list.  Because 
you have already specified the loaded registers gcc already knows that
these registers will be modified.  Ordinarily I wouldn't think that
would be a problem, but the GCC info pages state that "The input
operands are guaranteed not to use any of the clobbered registers."
There's clearly a contradiction here, and I would hope GCC flags
this as an error, or at least gives a warning.

Eric
-- 
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korpela AT ssl DOT berkeley DOT edu            |  stopped.
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