1 | ; Project name : XTIDE Universal BIOS |
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2 | ; Description : Functions for generating and accessing drive |
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3 | ; information to be displayed on boot menu. |
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4 | |
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5 | ; Section containing code |
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6 | SECTION .text |
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7 | |
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8 | ;-------------------------------------------------------------------- |
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9 | ; Creates new BOOTMENUINFO struct for detected hard disk. |
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10 | ; |
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11 | ; BootMenuInfo_CreateForHardDisk |
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12 | ; Parameters: |
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13 | ; DL: Drive number |
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14 | ; DS:DI: Ptr to Disk Parameter Table |
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15 | ; ES:SI: Ptr to 512-byte ATA information read from the drive |
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16 | ; Returns: |
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17 | ; ES:BX: Ptr to BOOTMENUINFO (if successful) |
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18 | ; Corrupts registers: |
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19 | ; AX, BX, CX, DX, DI |
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20 | ;-------------------------------------------------------------------- |
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21 | BootMenuInfo_CreateForHardDisk: |
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22 | call BootMenuInfo_ConvertDPTtoBX ; ES:BX now points to new BOOTMENUINFO |
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23 | push bx ; Preserve for return |
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24 | |
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25 | mov di, bx ; Starting pointer at beginning of structure |
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26 | |
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27 | ; Store Drive Name |
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28 | push ds ; Preserve RAMVARS |
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29 | push si |
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30 | |
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31 | push es ; ES copied to DS |
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32 | pop ds |
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33 | |
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34 | add si, BYTE ATA1.strModel ; DS:SI now points drive name |
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35 | lea di, [bx+BOOTMENUINFO.szDrvName] ; ES:DI now points to name destination |
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36 | mov cx, MAX_HARD_DISK_NAME_LENGTH / 2 ; Max number of WORDs allowed |
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37 | .CopyNextWord: |
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38 | lodsw |
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39 | xchg al, ah ; Change endianness |
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40 | stosw |
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41 | loop .CopyNextWord |
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42 | xor ax, ax ; Zero AX and clear CF |
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43 | stosw ; Terminate with NULL |
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44 | |
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45 | pop si |
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46 | pop ds |
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47 | pop bx |
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48 | |
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49 | ret |
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50 | |
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51 | |
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52 | ;-------------------------------------------------------------------- |
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53 | ; BootMenuInfo_GetTotalSectorCount |
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54 | ; Parameters: |
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55 | ; DS:DI: DPT Pointer |
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56 | ; Returns: |
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57 | ; BX:DX:AX: 48-bit sector count |
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58 | ; Corrupts registers: |
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59 | ; CX |
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60 | ;-------------------------------------------------------------------- |
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61 | ALIGN JUMP_ALIGN |
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62 | BootMenuInfo_GetTotalSectorCount: |
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63 | test BYTE [di+DPT.bFlagsLow], FLG_DRVNHEAD_LBA |
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64 | jnz SHORT .ReturnFullCapacity |
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65 | jmp AH15h_GetSectorCountToBXDXAX |
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66 | .ReturnFullCapacity: |
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67 | jmp AccessDPT_GetLbaSectorCountToBXDXAX |
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68 | |
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69 | |
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70 | ;-------------------------------------------------------------------- |
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71 | ; Returns offset to BOOTMENUINFO based on DPT pointer. |
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72 | ; |
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73 | ; BootMenuInfo_ConvertDPTtoBX |
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74 | ; Parameters: |
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75 | ; DS:DI: DPT Pointer |
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76 | ; Returns: |
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77 | ; BX: Offset to BOOTMENUINFO struct |
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78 | ; Corrupts registers: |
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79 | ; AX |
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80 | ;-------------------------------------------------------------------- |
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81 | ALIGN JUMP_ALIGN |
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82 | BootMenuInfo_ConvertDPTtoBX: |
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83 | mov ax, di |
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84 | sub ax, RAMVARS_size ; subtract off base of DPTs |
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85 | mov bl, DPT_BOOTMENUINFO_SIZE_MULTIPLIER ; BOOTMENUINFO's are a whole number multiple of DPT size |
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86 | mul bl |
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87 | add ax, BOOTVARS.rgBootNfo ; add base of BOOTMENUINFO |
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88 | xchg ax, bx |
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89 | ret |
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