Add a workaround for AST BIOS.

ChangeLog

@@ -1,3 +1,9 @@
+2001-12-19  Yoshinori K. Okuji  <okuji@gnu.org>
+
+	From Michael Sullivan <mike@trdlnk.com>:
+	* stage1/stage1.S (real_start): Added a workaround for AST BIOS,
+	because it clobbers %dl with INT 13, AH=41H.
+
 2001-12-19  Yoshinori K. Okuji  <okuji@gnu.org>
 
 	* stage2/fsys_fat.c (fat_read): Fix the contradictory comment.

THANKS

@@ -60,6 +60,7 @@ Matt Yourst <yourst@mit.edu>
 Matthias Granberry <matthias@slurpee.org>
 Matthias Kretschmer <m.kretschmer@bsdger.org>
 Michael Hohmuth <hohmuth@innocent.com>
+Michael Sullivan <mike@trdlnk.com>
 Mike Meyer <mwm@mired.org>
 Miles Bader <miles@gnu.org>
 Neal H Walfield <neal@walfield.org>

stage1/stage1.S

@@ -1,7 +1,7 @@
 /* -*-Asm-*- */
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 1999,2000   Free Software Foundation, Inc.
+ *  Copyright (C) 1999,2000,2001   Free Software Foundation, Inc.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -148,6 +148,13 @@ real_start:
 	movw	$0x55aa, %bx
 	int	$0x13
 
+	/* 
+	 *  %dl may have been clobbered by INT 13, AH=41H.
+	 *  This happens, for example, with AST BIOS 1.04.
+	 */
+	popw	%dx
+	pushw	%dx
+
 	/* use CHS if fails */
 	jc	chs_mode
 	cmpw	$0xaa55, %bx