1 | ; File name : Int19hMenu.asm |
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2 | ; Project name : IDE BIOS |
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3 | ; Created date : 25.3.2010 |
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4 | ; Last update : 12.4.2010 |
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5 | ; Author : Tomi Tilli |
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6 | ; Description : Int 19h BIOS functions for Boot Menu. |
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7 | |
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8 | ; Section containing code |
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9 | SECTION .text |
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10 | |
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11 | ;-------------------------------------------------------------------- |
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12 | ; Initial Boot Menu Loader. |
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13 | ; Prepares BOOTVARS for displaying Boot Menu and accepting |
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14 | ; callbacks from INT 18h and 19h. |
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15 | ; |
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16 | ; Int19hMenu_BootLoader |
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17 | ; Parameters: |
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18 | ; Nothing |
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19 | ; Returns: |
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20 | ; Jumps to Int19hMenu_Display, then never returns |
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21 | ;-------------------------------------------------------------------- |
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22 | ALIGN JUMP_ALIGN |
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23 | Int19hMenu_BootLoader: |
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24 | LOAD_BDA_SEGMENT_TO ds, ax |
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25 | call BootVars_StorePostStackPointer |
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26 | call BootVars_StoreSystemInt18hAndInstallOurs |
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27 | |
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28 | ; Install new INT 19h handler now that BOOTVARS has been initialized |
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29 | mov WORD [INTV_BOOTSTRAP*4], Int19hMenu_Display |
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30 | mov WORD [INTV_BOOTSTRAP*4+2], cs |
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31 | ; Fall to Int19hMenu_Display |
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32 | |
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33 | ;-------------------------------------------------------------------- |
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34 | ; Displays Boot Menu so user can select drive to boot from. |
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35 | ; |
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36 | ; Int19hMenu_Display |
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37 | ; Parameters: |
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38 | ; Nothing |
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39 | ; Returns: |
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40 | ; Never returns |
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41 | ;-------------------------------------------------------------------- |
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42 | ALIGN JUMP_ALIGN |
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43 | Int19hMenu_Display: |
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44 | sti ; Enable interrupts |
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45 | call BootVars_SwitchToBootMenuStack |
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46 | call RamVars_GetSegmentToDS |
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47 | ; Fall to Int19hMenu_ProcessMenuSelectionsUntilBootable |
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48 | |
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49 | ;-------------------------------------------------------------------- |
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50 | ; Processes user menu selections until bootable drive is selected. |
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51 | ; |
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52 | ; Int19hMenu_ProcessMenuSelectionsUntilBootable |
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53 | ; Parameters: |
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54 | ; DS: RAMVARS segment |
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55 | ; Returns: |
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56 | ; Never returns |
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57 | ;-------------------------------------------------------------------- |
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58 | ALIGN JUMP_ALIGN |
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59 | Int19hMenu_ProcessMenuSelectionsUntilBootable: |
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60 | call Int19hMenu_GetDriveOrFunctionFromBootMenu |
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61 | jc SHORT Int19hMenu_ExecuteSelectedFunction |
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62 | call Int19h_TryToLoadBootSectorFromDL |
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63 | jnc SHORT Int19hMenu_ProcessMenuSelectionsUntilBootable ; Boot failure |
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64 | call BootVars_SwitchBackToPostStack |
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65 | jmp SHORT Int19h_JumpToBootSector |
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66 | |
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67 | |
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68 | ;-------------------------------------------------------------------- |
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69 | ; Selects Floppy or Hard Disk Drive to boot from or some function. |
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70 | ; |
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71 | ; Int19hMenu_GetDriveOrFunctionFromBootMenu |
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72 | ; Parameters: |
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73 | ; DS: RAMVARS segment |
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74 | ; Returns: |
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75 | ; DX: Drive number (translated, 00h or 80h) or |
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76 | ; Function ID |
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77 | ; CF: Cleared if drive selected |
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78 | ; Set if function selected |
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79 | ; Corrupts registers: |
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80 | ; All non segment regs |
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81 | ;-------------------------------------------------------------------- |
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82 | ALIGN JUMP_ALIGN |
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83 | Int19hMenu_GetDriveOrFunctionFromBootMenu: |
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84 | call BootMenu_DisplayAndReturnSelection |
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85 | jc SHORT .ReturnFunction |
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86 | call DriveXlate_ToOrBack ; Translate drive number |
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87 | clc |
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88 | ALIGN JUMP_ALIGN |
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89 | .ReturnFunction: |
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90 | ret |
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91 | |
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92 | |
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93 | ;-------------------------------------------------------------------- |
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94 | ; Executes any function (non-drive) selected from Boot Menu. |
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95 | ; |
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96 | ; Int19hMenu_ExecuteSelectedFunction |
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97 | ; Parameters: |
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98 | ; DX: Function ID (selected from Boot Menu) |
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99 | ; DS: RAMVARS segment |
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100 | ; Returns: |
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101 | ; Nothing |
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102 | ; Corrupts registers: |
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103 | ; All non segment regs |
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104 | ;-------------------------------------------------------------------- |
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105 | ALIGN JUMP_ALIGN |
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106 | Int19hMenu_ExecuteSelectedFunction: |
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107 | ePUSH_T ax, Int19hMenu_ProcessMenuSelectionsUntilBootable |
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108 | test dx, dx ; 0, IDF_BOOTMNU_ROM |
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109 | jz SHORT .Int18hRomBoot |
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110 | ret |
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111 | ALIGN JUMP_ALIGN |
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112 | .Int18hRomBoot: |
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113 | call BootVars_RestoreSystemInt18h |
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114 | call BootVars_SwitchBackToPostStack |
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115 | call Int19h_BootFailure ; Should never return |
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116 | jmp SHORT Int19hMenu_BootLoader ; Status unknown so reinitialize boot loader |
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