[117] | 1 | ; Project name : XTIDE Universal BIOS
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[3] | 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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[148] | 12 | ; DL: Translated Drive number
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| 13 | ; DS:DI: Ptr to DPT (in RAMVARS segment)
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[150] | 14 | ; SS:BP: Ptr to IDEPACK
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| 15 | ; Returns with INTPACK:
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[3] | 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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[150] | 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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[3] | 30 |
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[148] | 31 | xor ah, ah
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[150] | 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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[148] | 34 | jmp Int13h_ReturnFromHandlerWithoutStoringErrorCode
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[150] | 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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[155] | 61 | call Address_ExtractLCHSparametersFromOldInt13hAddress
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[150] | 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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