1 | ; File name : HDrvSel.asm |
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2 | ; Project name : IDE BIOS |
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3 | ; Created date : 25.2.2010 |
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4 | ; Last update : 13.4.2010 |
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5 | ; Author : Tomi Tilli |
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6 | ; Description : Functions for selecting Master or Slave drive. |
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7 | |
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8 | ; Section containing code |
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9 | SECTION .text |
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10 | |
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11 | ;-------------------------------------------------------------------- |
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12 | ; Selects Master or Slave drive for transferring data. |
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13 | ; This means that interrupts will be enabled if so configured in |
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14 | ; IDEVARS. This function returns after drive is ready to accept commands. |
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15 | ; |
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16 | ; HDrvSel_SelectDriveForDataTransfer |
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17 | ; Parameters: |
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18 | ; DS:DI: Ptr to DPT |
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19 | ; Returns: |
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20 | ; AH: BIOS Error code |
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21 | ; CF: 0 if drive selected successfully |
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22 | ; 1 if any error |
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23 | ; Corrupts registers: |
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24 | ; AL, BX |
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25 | ;-------------------------------------------------------------------- |
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26 | ALIGN JUMP_ALIGN |
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27 | HDrvSel_SelectDriveForDataTransfer: |
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28 | mov al, [di+DPT.bDrvCtrl] ; Load Device Control Byte |
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29 | ; Fall to HDrvSel_SelectDriveAndSetControlByte |
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30 | |
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31 | ;-------------------------------------------------------------------- |
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32 | ; Selects Master or Slave drive. |
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33 | ; Device Control Byte can be used to enable or disable interrupts. |
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34 | ; This function returns only after drive is ready to accept commands. |
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35 | ; |
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36 | ; HDrvSel_SelectDriveAndSetControlByte |
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37 | ; Parameters: |
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38 | ; AL: Device Control Byte (to enable/disable interrupts) |
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39 | ; DS:DI: Ptr to DPT |
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40 | ; Returns: |
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41 | ; AH: BIOS Error code |
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42 | ; CF: 0 if drive selected successfully |
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43 | ; 1 if any error |
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44 | ; Corrupts registers: |
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45 | ; AL, BX |
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46 | ;-------------------------------------------------------------------- |
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47 | ;ALIGN JUMP_ALIGN |
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48 | HDrvSel_SelectDriveAndSetControlByte: |
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49 | push dx |
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50 | push cx |
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51 | |
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52 | ; Output Device Control Register to enable/disable interrupts |
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53 | call HDrvSel_OutputDeviceControlByte |
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54 | |
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55 | ; Select Master or Slave drive |
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56 | mov dx, [RAMVARS.wIdeBase] |
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57 | add dx, BYTE REG_IDE_DRVHD |
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58 | mov al, [di+DPT.bDrvSel] ; Load Master/Slave selection byte |
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59 | out dx, al ; Select drive |
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60 | |
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61 | ; Wait until drive is ready to accept commands |
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62 | call SoftDelay_BeforePollingStatusRegister |
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63 | call HStatus_WaitRdyDefTime |
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64 | pop cx |
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65 | pop dx |
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66 | ret |
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67 | |
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68 | |
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69 | ;-------------------------------------------------------------------- |
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70 | ; Outputs Device Control Byte to Device Control Register. |
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71 | ; |
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72 | ; HDrvSel_OutputDeviceControlByte |
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73 | ; Parameters: |
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74 | ; AL: Device Control Byte |
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75 | ; DS:DI: Ptr to Disk Parameter Table |
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76 | ; Returns: |
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77 | ; DX: Device Control Register address |
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78 | ; Corrupts registers: |
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79 | ; BX |
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80 | ;-------------------------------------------------------------------- |
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81 | ALIGN JUMP_ALIGN |
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82 | HDrvSel_OutputDeviceControlByte: |
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83 | eMOVZX bx, BYTE [di+DPT.bIdeOff] ; CS:BX now points to IDEVARS |
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84 | mov dx, [cs:bx+IDEVARS.wPortCtrl] ; Load Control Block base address |
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85 | add dx, BYTE REGW_IDEC_CTRL ; Add offset to Device Control Register |
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86 | out dx, al ; Output Device Control byte |
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87 | ret |
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88 | |
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89 | |
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90 | ;-------------------------------------------------------------------- |
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91 | ; Selects Master or Slave drive and disables interrupts. Interrupts should |
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92 | ; be disabled for commands that do not transfer data. |
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93 | ; This function returns after drive is ready to accept commands. |
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94 | ; |
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95 | ; HDrvSel_SelectDriveAndDisableIRQ |
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96 | ; Parameters: |
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97 | ; DS:DI: Ptr to DPT |
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98 | ; Returns: |
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99 | ; AH: BIOS Error code |
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100 | ; CF: 0 if drive selected successfully |
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101 | ; 1 if any error |
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102 | ; Corrupts registers: |
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103 | ; AL |
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104 | ;-------------------------------------------------------------------- |
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105 | ALIGN JUMP_ALIGN |
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106 | HDrvSel_SelectDriveAndDisableIRQ: |
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107 | push bx |
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108 | mov al, [di+DPT.bDrvCtrl] ; Load Device Control Byte |
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109 | or al, FLG_IDE_CTRL_nIEN ; Disable interrupts |
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110 | call HDrvSel_SelectDriveAndSetControlByte |
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111 | pop bx |
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112 | ret |
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