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 BootMenu_DisplayAndReturnSelection |
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56 | call DriveXlate_ToOrBack ; Translate drive number |
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57 | call Int19h_TryToLoadBootSectorFromDL |
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58 | jnc SHORT Int19hMenu_ProcessMenuSelectionsUntilBootable ; Boot failure, show menu again |
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59 | call BootVars_SwitchBackToPostStack |
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60 | jmp Int19h_JumpToBootSector |
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61 | |
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62 | |
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63 | ;-------------------------------------------------------------------- |
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64 | ; Int19hMenu_RomBoot |
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65 | ; Parameters: |
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66 | ; DS: RAMVARS segment |
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67 | ; Returns: |
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68 | ; Never returns |
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69 | ;-------------------------------------------------------------------- |
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70 | ALIGN JUMP_ALIGN |
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71 | Int19hMenu_RomBoot: |
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72 | call BootVars_SwitchBackToPostStack |
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73 | call Int19h_ClearSegmentsForBoot |
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74 | int INTV_BOOT_FAILURE ; Never returns |
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