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