Re: [Xen-devel] expecting string instruction after `rep' with latest SeaBIOS

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2014-06-30 at 15:07 +0200, Paolo Bonzini wrote:
> Il 30/06/2014 15:03, Ian Campbell ha scritto:
> > That line is:
> >                 // Acquire lock and take ownership of shared stack
> >         1:      rep nop
> >
> > I've also checked the preprocessed version and the nop isn't being
> > disappeared or anything like that.
> 
> "rep nop" is really just "pause".

Yes, that's how I was translating it in my head, which is why I thought
it was fine to write it like that.

> I think the assembler wants "rep; nop" instead.

That's right, I was just reaching the same conclusion. Build-tested
patch:

8<------------------------

From 0b05042b582a8992c15030406dcb220be82da8ce Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@xxxxxxxxxx>
Date: Mon, 30 Jun 2014 14:10:02 +0100
Subject: [PATCH] romlayout: Use "rep ; nop" not "rep nop".

Fixes:
  Compiling (16bit) out/romlayout.o
src/romlayout.S: Assembler messages:
src/romlayout.S:285: Error: expecting string instruction after `rep'
make: *** [out/romlayout.o] Error 1

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 src/romlayout.S |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/romlayout.S b/src/romlayout.S
index a931b32..a3ba965 100644
--- a/src/romlayout.S
+++ b/src/romlayout.S
@@ -282,7 +282,7 @@ entry_smp:
         jmp transition32
         .code32
         // Acquire lock and take ownership of shared stack
-1:      rep nop
+1:      rep ; nop
 2:      lock btsl $0, SMPLock
         jc 1b
         movl SMPStack, %esp
-- 
1.7.10.4




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