From: H. Peter Anvin <hpa@zytor.com>
Date: Thu, 12 Jul 2007 00:51:27 +0000 (-0700)
Subject: MBR: shave off another byte
X-Git-Tag: syslinux-3.52-pre4~3
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b19e0b33ad57d71635c55d9724cdff45daa24d73;p=platform%2Fupstream%2Fsyslinux.git

MBR: shave off another byte

Yet another byte bites the dust...
---

diff --git a/mbr/mbr.S b/mbr/mbr.S
index 0822b53..2a318be 100644
--- a/mbr/mbr.S
+++ b/mbr/mbr.S
@@ -93,12 +93,13 @@ next:
 	int	$0x13
 	andw	$0x3f, %cx	/* Sector count */
 	pushw	%cx		/* Save sectors on the stack */
-	xorw	%ax, %ax
-	pushw	%ax		/* High word of sectors/cylinder */
-	movb	%dh, %al	/* dh = number of heads */
-	incw	%ax		/* From 0-based to count */
+	movzbw	%dh, %ax	/* dh = max head */
+	incw	%ax		/* From 0-based max to count */
 	mulw	%cx		/* Heads*sectors -> sectors per cylinder */
-	pushw	%ax		/* Save sectors/cylinder on the stack */
+
+	/* Save sectors/cylinder on the stack */
+	pushw	%dx		/* High word */
+	pushw	%ax		/* Low word */
 
 	xorl	%eax, %eax	/* Base */
 	cdq			/* Root (%edx <- 0) */