Initial /boot stuff (from Mickey)

1 files changed, 187 insertions, 0 deletions

diff --git a/sys/arch/i386/stand/libsa/biosdisk.S b/sys/arch/i386/stand/libsa/biosdisk.S
new file mode 100644
index 00000000000..f036d0f95c0
--- /dev/null
+++ b/sys/arch/i386/stand/libsa/biosdisk.S
@@ -0,0 +1,187 @@
+/*	$OpenBSD: biosdisk.S,v 1.2 1997/03/31 03:12:11 weingart Exp $	*/
+
+/*
+ * Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
+ *
+ * Mach Operating System
+ * Copyright (c) 1992, 1991 Carnegie Mellon University
+ * All Rights Reserved.
+ * 
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ * 
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ * 
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ */
+
+/*
+  Copyright 1988, 1989, 1990, 1991, 1992 
+   by Intel Corporation, Santa Clara, California.
+
+                All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and
+its documentation for any purpose and without fee is hereby
+granted, provided that the above copyright notice appears in all
+copies and that both the copyright notice and this permission notice
+appear in supporting documentation, and that the name of Intel
+not be used in advertising or publicity pertaining to distribution
+of the software without specific, written prior permission.
+
+INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
+INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
+IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
+NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
+WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <machine/asm.h>
+#define	addr32	.byte 0x67
+#define	data32	.byte 0x66
+
+/*
+# BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory
+#	Call with	%ah = 0x2
+#			%al = number of sectors
+#			%ch = cylinder
+#			%cl = sector
+#			%dh = head
+#			%dl = drive (0x80 for hard disk, 0x0 for floppy disk)
+#			%es:%bx = segment:offset of buffer
+#	Return:		
+#			%al = 0x0 on success; err code on failure
+*/
+ENTRY(biosread)
+	pushl	%ebp
+	movl	%esp, %ebp
+	pushl	%ebx
+	pushl	%esi
+	pushl	%edi
+	push	%es
+
+	movb	8(%ebp), %dl	# device
+	movw	12(%ebp), %cx
+	xchgb	%ch, %cl	# cylinder; the highest 2 bits of cyl is in %cl
+	rorb	$2, %cl
+	movb	16(%ebp), %dh	# head
+	movb	20(%ebp), %al
+	orb	%al, %cl
+	incb	%cl		# sector; sec starts from 1, not 0
+	movb	$0x2, %ah	# subfunction
+	movb	24(%ebp), %al	# number of sectors
+	movl	%eax, %esi	# save this against mode switch
+	movl	28(%ebp), %ebx	# offset
+
+
+	# prot_to_real will set %es to BOOTSEG
+	# Which means %cs == %es.
+	# XXX - This hoses things severly.  Better
+	# recoup %es to point to the base of the given
+	# buffer, and let %bx be the index into it,
+	# that way we can read a max of 64K give or
+	# take 15 bytes anyways.
+
+	# Save %es in %edi
+	movl	%ebx, %eax
+	shrl	$4, %eax
+	movl	%eax, %edi
+	andl	$0xF, %ebx
+
+	call	_C_LABEL(prot_to_real)	# enter real mode
+
+	# Restore %es
+	movl	%di, %es
+
+	# Restore %ax
+	movl	%si, %ax
+
+	int	$0x13
+	setc	%bl
+
+	data32
+	call	_C_LABEL(real_to_prot) # back to protected mode
+
+	movzbl	%bl, %eax	# return value in %ax
+
+	pop		%es
+	popl	%edi
+	popl	%esi
+	popl	%ebx
+	popl	%ebp
+	ret
+
+ENTRY(bioswrite)
+
+	movl	$1, %eax
+	ret
+
+/*
+#
+# biosdinfo():  return a word that represents the
+#	max number of sectors and  heads and drives for this device
+#
+*/
+
+ENTRY(biosdinfo)
+	pushl	%ebp
+	movl	%esp, %ebp
+	pushl	%ebx
+	pushl	%esi
+	pushl	%edi
+
+	movb	8(%ebp), %dl		# diskinfo(drive #)
+
+	call	_C_LABEL(prot_to_real)	# enter real mode
+
+	movb	$0x08, %ah		# ask for disk info
+	int	$0x13
+	jnc	ok
+
+	/*
+	 * Urk.  Call failed.  It is not supported for floppies by old BIOS's.
+	 * Guess it's a 15-sector floppy.  Initialize all the registers for
+	 * documentation, although we only need head and sector counts.
+	 */
+	xorl	%bx, %bx		# %bh = 0
+	incw %bx; incw %bx		# %bl bits 0-3 = drive type, 2 = 1.2M
+	movb	$79, %ch		# max track
+	movb	$15, %cl		# max sector
+	xorl	%dx, %dx
+	incw	%dx			# floppy drives installed
+	movb	%dl, %dh		# max head
+	# es:di = parameter table
+	# carry = 0
+
+ok:
+	data32
+	call	_C_LABEL(real_to_prot)	# back to protected mode
+
+	xorl	%eax, %eax
+
+	/* form a longword representing all this gunk */
+	movb	%dh, %ah		# max head
+	andb	$0x3f, %cl		# mask of cylinder gunk
+	movb	%cl, %al		# max sector (and # sectors)
+
+	popl	%edi
+	popl	%esi
+	popl	%ebx
+	popl	%ebp
+	ret
+