1 | ; Project name : XTIDE Universal BIOS
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2 | ; Description : Int 13h function AH=15h, Read Disk Drive Size.
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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 | ; Int 13h function AH=15h, Read Disk Drive Size.
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9 | ;
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10 | ; AH15h_HandlerForReadDiskDriveSize
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11 | ; Parameters:
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12 | ; DL: Translated Drive number
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13 | ; DS:DI: Ptr to DPT (in RAMVARS segment)
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14 | ; SS:BP: Ptr to IDEPACK
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15 | ; Returns with INTPACK:
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16 | ; If succesfull:
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17 | ; AH: 3 (Hard disk accessible)
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18 | ; CX:DX: Total number of sectors
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19 | ; CF: 0
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20 | ; If failed:
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21 | ; AH: 0 (Drive not present)
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22 | ; CX:DX: 0
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23 | ; CF: 1
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24 | ;--------------------------------------------------------------------
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25 | ALIGN JUMP_ALIGN
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26 | AH15h_HandlerForReadDiskDriveSize:
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27 | call AH15h_GetSectorCountToDXAX
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28 | mov [bp+IDEPACK.intpack+INTPACK.cx], dx ; HIWORD to CX
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29 | mov [bp+IDEPACK.intpack+INTPACK.dx], ax ; LOWORD to DX
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30 |
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31 | xor ah, ah
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32 | call Int13h_SetErrorCodeToIntpackInSSBPfromAH ; Store success to BDA and CF
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33 | mov BYTE [bp+IDEPACK.intpack+INTPACK.ah], 3 ; Type code = Hard disk
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34 | jmp Int13h_ReturnFromHandlerWithoutStoringErrorCode
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35 |
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36 |
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37 | ;--------------------------------------------------------------------
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38 | ; AH15h_GetSectorCountFromForeignDriveToDXAX:
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39 | ; AH15h_GetSectorCountToDXAX:
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40 | ; Parameters:
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41 | ; DL: Drive number
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42 | ; DS: RAMVARS segment
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43 | ; DS:DI: Ptr to DPT (AH15h_GetSectorCount only)
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44 | ; Returns:
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45 | ; DX:AX: Total sector count
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46 | ; BX: Zero
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47 | ; Corrupts registers:
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48 | ; CX
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49 | ;--------------------------------------------------------------------
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50 | AH15h_GetSectorCountFromForeignDriveToDXAX:
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51 | mov ah, GET_DRIVE_PARAMETERS
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52 | call Int13h_CallPreviousInt13hHandler
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53 | jmp SHORT ConvertAH08hReturnValuesToSectorCount
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54 |
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55 | ALIGN JUMP_ALIGN
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56 | AH15h_GetSectorCountToDXAX:
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57 | call AH8h_GetDriveParameters
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58 | ; Fall to ConvertAH08hReturnValuesToSectorCount
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59 |
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60 | ConvertAH08hReturnValuesToSectorCount:
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61 | call Address_ExtractLCHSparametersFromOldInt13hAddress
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62 | xor ax, ax ; Zero AX
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63 | inc cx ; Max cylinder number to cylinder count
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64 | xchg al, bh ; AX=Max head number, BX=Sectors per track
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65 | inc ax ; AX=Head count
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66 | mul bx ; AX=Head count * Sectors per track
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67 | mul cx ; DX:AX = Total sector count
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68 | xor bx, bx ; Zero BX for 48-bit sector count (and clear CF)
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69 | ret
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