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 32 int25_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 */ 45 1: 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 57 int26_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 */ 70 1: 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
