| 1 | ; Project name : XTIDE Universal BIOS
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| 2 | ; Description : Functions for selecting Master or Slave drive.
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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 | ; Selects Master or Slave drive for transferring data.
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| 9 | ; This means that interrupts will be enabled if so configured in
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| 10 | ; IDEVARS. This function returns after drive is ready to accept commands.
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| 11 | ;
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| 12 | ; HDrvSel_SelectDriveForDataTransfer
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| 13 | ; Parameters:
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| 14 | ; DS:DI: Ptr to DPT
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| 15 | ; Returns:
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| 16 | ; AH: BIOS Error code
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| 17 | ; CF: 0 if drive selected successfully
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| 18 | ; 1 if any error
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| 19 | ; Corrupts registers:
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| 20 | ; AL, BX
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| 21 | ;--------------------------------------------------------------------
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| 22 | ALIGN JUMP_ALIGN
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| 23 | HDrvSel_SelectDriveForDataTransfer:
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| 24 | mov al, [di+DPT.bDrvCtrl] ; Load Device Control Byte
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| 25 | ; Fall to HDrvSel_SelectDriveAndSetControlByte
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| 26 |
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| 27 | ;--------------------------------------------------------------------
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| 28 | ; Selects Master or Slave drive.
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| 29 | ; Device Control Byte can be used to enable or disable interrupts.
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| 30 | ; This function returns only after drive is ready to accept commands.
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| 31 | ;
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| 32 | ; HDrvSel_SelectDriveAndSetControlByte
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| 33 | ; Parameters:
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| 34 | ; AL: Device Control Byte (to enable/disable interrupts)
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| 35 | ; DS:DI: Ptr to DPT
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| 36 | ; Returns:
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| 37 | ; AH: BIOS Error code
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| 38 | ; CF: 0 if drive selected successfully
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| 39 | ; 1 if any error
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| 40 | ; Corrupts registers:
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| 41 | ; AL, BX
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| 42 | ;--------------------------------------------------------------------
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| 43 | ;ALIGN JUMP_ALIGN
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| 44 | HDrvSel_SelectDriveAndSetControlByte:
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| 45 | push dx
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| 46 | push cx
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| 47 |
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| 48 | ; Output Device Control Register to enable/disable interrupts
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| 49 | call HDrvSel_OutputDeviceControlByte
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| 50 |
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| 51 | ; Select Master or Slave drive
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| 52 | mov dx, [RAMVARS.wIdeBase]
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| 53 | add dx, BYTE REG_IDE_DRVHD
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| 54 | mov al, [di+DPT.bDrvSel] ; Load Master/Slave selection byte
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| 55 | out dx, al ; Select drive
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| 56 |
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| 57 | ; Wait until drive is ready to accept commands
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| 58 | call HStatus_WaitRdyDefTime
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| 59 | pop cx
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| 60 | pop dx
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| 61 | ret
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| 62 |
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| 63 |
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| 64 | ;--------------------------------------------------------------------
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| 65 | ; Outputs Device Control Byte to Device Control Register.
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| 66 | ;
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| 67 | ; HDrvSel_OutputDeviceControlByte
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| 68 | ; Parameters:
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| 69 | ; AL: Device Control Byte
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| 70 | ; DS:DI: Ptr to Disk Parameter Table
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| 71 | ; Returns:
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| 72 | ; DX: Device Control Register address
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| 73 | ; Corrupts registers:
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| 74 | ; BX
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| 75 | ;--------------------------------------------------------------------
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| 76 | ALIGN JUMP_ALIGN
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| 77 | HDrvSel_OutputDeviceControlByte:
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| 78 | eMOVZX bx, BYTE [di+DPT.bIdeOff] ; CS:BX now points to IDEVARS
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| 79 | mov dx, [cs:bx+IDEVARS.wPortCtrl] ; Load Control Block base address
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| 80 | add dx, BYTE REGW_IDEC_CTRL ; Add offset to Device Control Register
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| 81 | out dx, al ; Output Device Control byte
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| 82 | ret
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| 83 |
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| 84 |
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| 85 | ;--------------------------------------------------------------------
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| 86 | ; Selects Master or Slave drive and disables interrupts. Interrupts should
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| 87 | ; be disabled for commands that do not transfer data.
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| 88 | ; This function returns after drive is ready to accept commands.
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| 89 | ;
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| 90 | ; HDrvSel_SelectDriveAndDisableIRQ
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| 91 | ; Parameters:
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| 92 | ; DS:DI: Ptr to DPT
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| 93 | ; Returns:
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| 94 | ; AH: BIOS Error code
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| 95 | ; CF: 0 if drive selected successfully
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| 96 | ; 1 if any error
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| 97 | ; Corrupts registers:
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| 98 | ; AL
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| 99 | ;--------------------------------------------------------------------
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| 100 | ALIGN JUMP_ALIGN
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| 101 | HDrvSel_SelectDriveAndDisableIRQ:
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| 102 | push bx
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| 103 | mov al, [di+DPT.bDrvCtrl] ; Load Device Control Byte
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| 104 | or al, FLG_IDE_CTRL_nIEN ; Disable interrupts
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| 105 | call HDrvSel_SelectDriveAndSetControlByte
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| 106 | pop bx
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| 107 | ret
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