From 92d1d619c033353a5e532b7118daee1a403f08ca Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@linux.intel.com>
Date: Fri, 11 Jun 2010 17:21:35 -0700
Subject: gptmbr: save four bytes

Save four bytes by observing that none of our code relies on
saturate_stosl not actually corrupting %eax.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 mbr/gptmbr.S | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

(limited to 'mbr')

diff --git a/mbr/gptmbr.S b/mbr/gptmbr.S
index 42887dbd..e8c60c00 100644
--- a/mbr/gptmbr.S
+++ b/mbr/gptmbr.S
@@ -222,15 +222,20 @@ boot:
 	cli
 	jmpw	*%sp		/* %sp == bootsec */
 
+/*
+ * Store the value in %eax to %di iff %edx == 0, otherwise store -1.
+ * Returns the value that was actually written in %eax.
+ */
 saturate_stosl:
-	pushl	%eax
 	andl	%edx,%edx
 	jz 1f
 	orl	$-1,%eax
 1:	stosl
-	popl	%eax
 	ret
 
+/*
+ * Increment %edx:%eax
+ */
 inc64:
 	addl	$1,%eax
 	adcl	$0,%edx
-- 
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