1/* ----------------------------------------------------------------------- *
2 *
3 *   Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
4 *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
5 *
6 *   This program is free software; you can redistribute it and/or modify
7 *   it under the terms of the GNU General Public License as published by
8 *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
9 *   Boston MA 02111-1307, USA; either version 2 of the License, or
10 *   (at your option) any later version; incorporated herein by reference.
11 *
12 * ----------------------------------------------------------------------- */
13
14/*
15 * int 0x25 and 0x26 direct sector access
16 *
17 * Use assembly wrapper functions for these system calls, since unlike
18 * int 0x21 calls they are "dirty" and can destroy unrelated registers.
19 *
20 * NOTE: these all assume the data buffer is in the data segment, i.e.
21 * %ds == %es == dio.bufseg.
22 *
23 * Usage: int int25_read_sector(drive, dio)
24 * Usage: int int26_write_sector(drive, dio)
25 */
26
27	.code16gcc
28	.text
29
30	.globl	int25_read_sector
31	.type	int25_read_sector, @function
32int25_read_sector:
33	pushl	%ebp
34	pushl	%edi
35	pushl	%esi
36	pushl	%ebx
37
38	decw	%ax		/* AL = drive number (0 = A:) */
39	movw	%dx, %bx	/* BX = dio structure */
40	movw	6(%bx), %dx	/* DX = data buffer */
41	movw	$-1, %cx
42	int	$0x25
43	jc	1f
44	xorw	%ax, %ax	/* Error code: 0 = no error */
451:
46	popfw
47	movzwl	%ax, %eax
48	popl	%ebx
49	popl	%esi
50	popl	%edi
51	popl	%ebp
52	retl
53	.size	int25_read_sector, .-int25_read_sector
54
55	.globl	int26_write_sector
56	.type	int26_write_sector, @function
57int26_write_sector:
58	pushl	%ebp
59	pushl	%edi
60	pushl	%esi
61	pushl	%ebx
62
63	decw	%ax		/* AL = drive number (0 = A:) */
64	movw	%dx, %bx	/* BX = dio structure */
65	movw	6(%bx), %dx	/* DX = data buffer */
66	movw	$-1, %cx
67	int	$0x26
68	jc	1f
69	xorw	%ax, %ax	/* Error code: 0 = no error */
701:
71	popfw
72	movzwl	%ax, %eax
73	popl	%ebx
74	popl	%esi
75	popl	%edi
76	popl	%ebp
77	retl
78	.size	int26_write_sector, .-int26_write_sector
79