From 1d4df6991d08489312399e6c8cf99048187d2acd Mon Sep 17 00:00:00 2001
From: okuji <okuji@localhost>
Date: Fri, 30 Jul 1999 09:59:34 +0000
Subject: [PATCH] avoid bogus BIOSes' bug in get_diskinfo_standard

---
 ChangeLog    | 6 ++++++
 stage2/asm.S | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 480056013..8e522c355 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+1999-07-30  OKUJI Yoshinori  <okuji@kuicr.kyoto-u.ac.jp>
+
+	From Pavel Roskin <pavel_roskin@geocities.com>:
+	* stage2/asm.S (get_diskinfo_standard): If the number of sectors
+	returned is zero, then return an error code, even if non-carrier.
+	
 1999-07-15  Gordon Matzigkeit  <gord@zen.fig.org>
 
 	* docs/Makefile.am (grub.info): Use an ugly hack to downgrade
diff --git a/stage2/asm.S b/stage2/asm.S
index 3143737e9..2bf294ef6 100644
--- a/stage2/asm.S
+++ b/stage2/asm.S
@@ -596,6 +596,15 @@ ENTRY(get_diskinfo_standard)
 	.code16
 	movb	$0x8, %ah
 	int	$0x13		/* do the operation */
+	/* check if successful */
+	testb	%ah, %ah
+	jnz	1f
+	/* bogus BIOSes may not return an error number */
+	testb	$0x3f, %cl	/* 0 sectors means no disk */
+	jnz	1f		/* if non-zero, then succeed */
+	/* XXX 0x60 is one of the unused error numbers */
+	movb	$0x60, %ah
+1:
 	movb	%ah, %bl	/* save return value in %bl */
 	/* back to protected mode */
 	data32