[3] | 1 | ; File name : FloppyDrive.asm |
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| 2 | ; Project name : IDE BIOS |
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| 3 | ; Created date : 25.3.2010 |
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[27] | 4 | ; Last update : 28.7.2010 |
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[3] | 5 | ; Author : Tomi Tilli |
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| 6 | ; Description : Various floppy drive related functions that |
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| 7 | ; Boot Menu uses. |
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| 8 | |
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| 9 | ; Section containing code |
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| 10 | SECTION .text |
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| 11 | |
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| 12 | ;-------------------------------------------------------------------- |
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| 13 | ; Checks is floppy drive handler installed to interrupt vector 40h. |
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| 14 | ; |
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| 15 | ; FloppyDrive_IsInt40hInstalled |
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| 16 | ; Parameters: |
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| 17 | ; ES: BDA and Interrupt Vector segment (zero) |
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| 18 | ; Returns: |
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| 19 | ; CF: Set if INT 40h is installed |
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| 20 | ; Cleared if INT 40h is not installed |
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| 21 | ; Corrupts registers: |
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| 22 | ; BX, CX, DI |
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| 23 | ;-------------------------------------------------------------------- |
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| 24 | ALIGN JUMP_ALIGN |
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| 25 | FloppyDrive_IsInt40hInstalled: |
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| 26 | cmp WORD [es:INTV_FLOPPY_FUNC*4+2], 0C000h ; Any ROM segment? |
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[27] | 27 | cmc |
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[3] | 28 | ret |
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| 29 | |
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| 30 | |
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| 31 | ;-------------------------------------------------------------------- |
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| 32 | ; Returns floppy drive type. |
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| 33 | ; PC/XT system do not support AH=08h but FLOPPY_TYPE_525_OR_35_DD |
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| 34 | ; is still returned for them. |
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| 35 | ; |
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| 36 | ; FloppyDrive_GetType |
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| 37 | ; Parameters: |
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| 38 | ; DL: Floppy Drive number |
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| 39 | ; Returns: |
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| 40 | ; BX: Floppy Drive Type: |
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| 41 | ; FLOPPY_TYPE_525_OR_35_DD |
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| 42 | ; FLOPPY_TYPE_525_DD |
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| 43 | ; FLOPPY_TYPE_525_HD |
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| 44 | ; FLOPPY_TYPE_35_DD |
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| 45 | ; FLOPPY_TYPE_35_HD |
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| 46 | ; FLOPPY_TYPE_35_ED |
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| 47 | ; CF: Set if AH=08h not supported (XT systems) or error |
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| 48 | ; Cleared if type read correctly (AT systems) |
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| 49 | ; Corrupts registers: |
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| 50 | ; AX, CX, DX, DI, ES |
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| 51 | ;-------------------------------------------------------------------- |
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| 52 | ALIGN JUMP_ALIGN |
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| 53 | FloppyDrive_GetType: |
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| 54 | mov ah, 08h ; Get Drive Parameters |
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| 55 | xor bx, bx ; FLOPPY_TYPE_525_OR_35_DD when function not supported |
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| 56 | int INTV_FLOPPY_FUNC |
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| 57 | ret |
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| 58 | |
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| 59 | |
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| 60 | ;-------------------------------------------------------------------- |
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| 61 | ; Returns number of Floppy Drives in system. |
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| 62 | ; |
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| 63 | ; FloppyDrive_GetCount |
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| 64 | ; Parameters: |
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| 65 | ; Nothing |
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| 66 | ; Returns: |
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| 67 | ; CX: Number of Floppy Drives |
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| 68 | ; Corrupts registers: |
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| 69 | ; Nothing |
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| 70 | ;-------------------------------------------------------------------- |
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| 71 | ALIGN JUMP_ALIGN |
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| 72 | FloppyDrive_GetCount: |
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| 73 | push es |
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| 74 | call FloppyDrive_GetCountFromBIOS |
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| 75 | jnc SHORT .CompareToUserMinimum |
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| 76 | call FloppyDrive_GetCountFromBDA |
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| 77 | ALIGN JUMP_ALIGN |
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| 78 | .CompareToUserMinimum: |
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| 79 | MAX_U cl, [cs:ROMVARS.bMinFddCnt] |
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| 80 | xor ch, ch |
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| 81 | pop es |
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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 | ; Reads Floppy Drive Count from BIOS. |
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| 87 | ; Does not work on most XT systems. Call FloppyDrive_GetCountFromBDA |
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| 88 | ; if this function fails. |
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| 89 | ; |
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| 90 | ; FloppyDrive_GetCountFromBIOS |
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| 91 | ; Parameters: |
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| 92 | ; Nothing |
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| 93 | ; Returns: |
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| 94 | ; CL: Number of Floppy Drives |
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| 95 | ; CF: Cleared if successfull |
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| 96 | ; Set if BIOS function not supported |
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| 97 | ; Corrupts registers: |
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| 98 | ; CH, ES |
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| 99 | ;-------------------------------------------------------------------- |
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| 100 | ALIGN JUMP_ALIGN |
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| 101 | FloppyDrive_GetCountFromBIOS: |
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| 102 | push di |
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| 103 | push dx |
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| 104 | push bx |
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| 105 | push ax |
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| 106 | |
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| 107 | mov ah, 08h ; Get Drive Parameters |
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| 108 | xor dx, dx ; Floppy Drive 00h |
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| 109 | int INTV_FLOPPY_FUNC |
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| 110 | mov cl, dl ; Number of Floppy Drives to CL |
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| 111 | |
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| 112 | pop ax |
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| 113 | pop bx |
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| 114 | pop dx |
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| 115 | pop di |
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| 116 | ret |
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| 117 | |
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| 118 | |
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| 119 | ;-------------------------------------------------------------------- |
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| 120 | ; Reads Floppy Drive Count (0...4) from BIOS Data Area. |
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| 121 | ; This function should be used only if FloppyDrive_GetCountFromBIOS fails. |
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| 122 | ; |
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| 123 | ; FloppyDrive_GetCountFromBDA |
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| 124 | ; Parameters: |
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| 125 | ; Nothing |
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| 126 | ; Returns: |
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| 127 | ; CL: Number of Floppy Drives |
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| 128 | ; Corrupts registers: |
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| 129 | ; CH, ES |
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| 130 | ;-------------------------------------------------------------------- |
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| 131 | ALIGN JUMP_ALIGN |
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| 132 | FloppyDrive_GetCountFromBDA: |
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| 133 | LOAD_BDA_SEGMENT_TO es, cx |
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| 134 | mov cl, [es:BDA.wEquipment] ; Load Equipment WORD low byte |
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| 135 | mov ch, cl ; Copy it to CH |
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| 136 | and cx, 0C001h ; Leave bits 15..14 and 0 |
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| 137 | eROL_IM ch, 2 ; EW low byte bits 7..6 to 1..0 |
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| 138 | add cl, ch ; CL = Floppy Drive count |
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| 139 | ret |
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