From: H. Peter Anvin <hpa@zytor.com>
Date: Mon, 25 Feb 2008 22:55:45 +0000 (-0800)
Subject: gptmbr: shuffle slightly to reduce register pressure
X-Git-Tag: syslinux-3.64-pre1~1^2~12
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=65b3053a5e868708e5a746b3e120902d71a45d4b;p=platform%2Fupstream%2Fsyslinux.git

gptmbr: shuffle slightly to reduce register pressure

Shuffle some code slightly to reduce register pressure; no size change
but this might make the code easier to follow and/or change.
---

diff --git a/mbr/gptmbr.S b/mbr/gptmbr.S
index 138ac51..80b26ed 100644
--- a/mbr/gptmbr.S
+++ b/mbr/gptmbr.S
@@ -178,8 +178,6 @@ found_part:
 	stosl
 	movl	40(%si),%eax
 	movl	48(%si),%edx
-	pushl	%eax
-	pushl	%edx
 	call	saturate_stosl		/* Partition start */
 
 	subl	32(%si),%eax
@@ -188,16 +186,15 @@ found_part:
 	call	saturate_stosl		/* Partition length */
 
 	rep; movsb			/* GPT entry follows MBR entry */
-	popl	%edx
-	popl	%eax
 	popw	%si
 
 /*
  * boot: invoke the actual bootstrap. %ds:%si points to the
- * partition information in memory, and %edx:%eax to the boot sector
- * on disk.
+ * partition information in memory.
  */
 boot:
+	movl	(40+16)(%si),%eax
+	movl	(48+16)(%si),%edx
 	call	read_sector
 	cmpw	$0xaa55, (bootsec+510)
 	jne	missing_os	/* Not a valid boot sector */