| 1 | /* ----------------------------------------------------------------------- * |
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| 2 | * |
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| 3 | * Copyright 1998-2008 H. Peter Anvin - All Rights Reserved |
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| 4 | * Copyright 2009 Intel Corporation; author: H. Peter Anvin |
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| 5 | * |
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| 6 | * This program is free software; you can redistribute it and/or modify |
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| 7 | * it under the terms of the GNU General Public License as published by |
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| 8 | * the Free Software Foundation, Inc., 53 Temple Place Ste 330, |
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| 9 | * Boston MA 02111-1307, USA; either version 2 of the License, or |
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| 10 | * (at your option) any later version; incorporated herein by reference. |
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| 11 | * |
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| 12 | * ----------------------------------------------------------------------- */ |
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| 13 | |
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| 14 | /* |
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| 15 | * int 0x25 and 0x26 direct sector access |
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| 16 | * |
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| 17 | * Use assembly wrapper functions for these system calls, since unlike |
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| 18 | * int 0x21 calls they are "dirty" and can destroy unrelated registers. |
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| 19 | * |
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| 20 | * NOTE: these all assume the data buffer is in the data segment, i.e. |
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| 21 | * %ds == %es == dio.bufseg. |
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| 22 | * |
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| 23 | * Usage: int int25_read_sector(drive, dio) |
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| 24 | * Usage: int int26_write_sector(drive, dio) |
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| 25 | */ |
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| 26 | |
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| 27 | .code16gcc |
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| 28 | .text |
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| 29 | |
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| 30 | .globl int25_read_sector |
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| 31 | .type int25_read_sector, @function |
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| 32 | int25_read_sector: |
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| 33 | pushl %ebp |
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| 34 | pushl %edi |
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| 35 | pushl %esi |
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| 36 | pushl %ebx |
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| 37 | |
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| 38 | decw %ax /* AL = drive number (0 = A:) */ |
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| 39 | movw %dx, %bx /* BX = dio structure */ |
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| 40 | movw 6(%bx), %dx /* DX = data buffer */ |
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| 41 | movw $-1, %cx |
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| 42 | int $0x25 |
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| 43 | jc 1f |
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| 44 | xorw %ax, %ax /* Error code: 0 = no error */ |
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| 45 | 1: |
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| 46 | popfw |
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| 47 | movzwl %ax, %eax |
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| 48 | popl %ebx |
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| 49 | popl %esi |
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| 50 | popl %edi |
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| 51 | popl %ebp |
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| 52 | retl |
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| 53 | .size int25_read_sector, .-int25_read_sector |
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| 54 | |
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| 55 | .globl int26_write_sector |
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| 56 | .type int26_write_sector, @function |
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| 57 | int26_write_sector: |
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| 58 | pushl %ebp |
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| 59 | pushl %edi |
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| 60 | pushl %esi |
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| 61 | pushl %ebx |
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| 62 | |
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| 63 | decw %ax /* AL = drive number (0 = A:) */ |
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| 64 | movw %dx, %bx /* BX = dio structure */ |
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| 65 | movw 6(%bx), %dx /* DX = data buffer */ |
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| 66 | movw $-1, %cx |
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| 67 | int $0x26 |
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| 68 | jc 1f |
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| 69 | xorw %ax, %ax /* Error code: 0 = no error */ |
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| 70 | 1: |
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| 71 | popfw |
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| 72 | movzwl %ax, %eax |
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| 73 | popl %ebx |
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| 74 | popl %esi |
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| 75 | popl %edi |
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| 76 | popl %ebp |
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| 77 | retl |
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| 78 | .size int26_write_sector, .-int26_write_sector |
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