| 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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