| [90] | 1 | ; Project name : XTIDE Universal BIOS |
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| [3] | 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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| [121] | 20 | ; Store POST stack pointer |
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| [3] | 21 | LOAD_BDA_SEGMENT_TO ds, ax |
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| [121] | 22 | STORE_POST_STACK_POINTER |
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| [3] | 23 | |
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| 24 | ; Install new INT 19h handler now that BOOTVARS has been initialized |
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| [96] | 25 | mov WORD [INTV_BOOTSTRAP*4], DisplayBootMenu |
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| [3] | 26 | mov WORD [INTV_BOOTSTRAP*4+2], cs |
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| [96] | 27 | ; Fall to DisplayBootMenu |
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| [3] | 28 | |
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| 29 | ;-------------------------------------------------------------------- |
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| [96] | 30 | ; DisplayBootMenu |
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| [3] | 31 | ; Parameters: |
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| 32 | ; Nothing |
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| 33 | ; Returns: |
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| 34 | ; Never returns |
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| 35 | ;-------------------------------------------------------------------- |
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| 36 | ALIGN JUMP_ALIGN |
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| [96] | 37 | DisplayBootMenu: |
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| [121] | 38 | SWITCH_TO_BOOT_MENU_STACK |
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| 39 | CALL_DISPLAY_LIBRARY InitializeDisplayContext |
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| [3] | 40 | call RamVars_GetSegmentToDS |
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| [96] | 41 | ; Fall to .ProcessMenuSelectionsUntilBootable |
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| [3] | 42 | |
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| 43 | ;-------------------------------------------------------------------- |
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| [96] | 44 | ; .ProcessMenuSelectionsUntilBootable |
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| [3] | 45 | ; Parameters: |
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| 46 | ; DS: RAMVARS segment |
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| 47 | ; Returns: |
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| 48 | ; Never returns |
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| 49 | ;-------------------------------------------------------------------- |
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| 50 | ALIGN JUMP_ALIGN |
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| [96] | 51 | .ProcessMenuSelectionsUntilBootable: |
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| [95] | 52 | call BootMenu_DisplayAndReturnSelection |
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| 53 | call DriveXlate_ToOrBack ; Translate drive number |
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| [96] | 54 | call BootSector_TryToLoadFromDriveDL |
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| 55 | jnc SHORT .ProcessMenuSelectionsUntilBootable ; Boot failure, show menu again |
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| [121] | 56 | SWITCH_BACK_TO_POST_STACK |
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| [96] | 57 | ; Fall to JumpToBootSector |
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| [3] | 58 | |
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| [96] | 59 | ;-------------------------------------------------------------------- |
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| 60 | ; JumpToBootSector |
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| 61 | ; Parameters: |
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| 62 | ; DL: Drive to boot from (translated, 00h or 80h) |
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| 63 | ; ES:BX: Ptr to boot sector |
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| 64 | ; Returns: |
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| 65 | ; Never returns |
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| 66 | ;-------------------------------------------------------------------- |
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| 67 | ALIGN JUMP_ALIGN |
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| 68 | JumpToBootSector: |
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| 69 | push es ; Push boot sector segment |
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| 70 | push bx ; Push boot sector offset |
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| 71 | call ClearSegmentsForBoot |
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| 72 | retf |
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| [3] | 73 | |
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| [96] | 74 | |
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| [3] | 75 | ;-------------------------------------------------------------------- |
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| [95] | 76 | ; Int19hMenu_RomBoot |
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| [3] | 77 | ; Parameters: |
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| 78 | ; DS: RAMVARS segment |
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| 79 | ; Returns: |
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| [95] | 80 | ; Never returns |
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| [3] | 81 | ;-------------------------------------------------------------------- |
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| 82 | ALIGN JUMP_ALIGN |
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| [95] | 83 | Int19hMenu_RomBoot: |
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| [121] | 84 | SWITCH_BACK_TO_POST_STACK |
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| [96] | 85 | call ClearSegmentsForBoot |
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| [95] | 86 | int INTV_BOOT_FAILURE ; Never returns |
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| [96] | 87 | |
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| 88 | |
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| 89 | ;-------------------------------------------------------------------- |
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| 90 | ; ClearSegmentsForBoot |
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| 91 | ; Parameters: |
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| 92 | ; Nothing |
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| 93 | ; Returns: |
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| [121] | 94 | ; DX: Zero |
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| [96] | 95 | ; DS=ES: Zero |
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| 96 | ; Corrupts registers: |
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| [121] | 97 | ; Nothing |
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| [96] | 98 | ;-------------------------------------------------------------------- |
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| 99 | ALIGN JUMP_ALIGN |
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| 100 | ClearSegmentsForBoot: |
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| [121] | 101 | xor dx, dx ; Device supported by INT 13h |
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| 102 | mov ds, dx |
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| 103 | mov es, dx |
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| [96] | 104 | ret |
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