| 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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| 4 | ; Last update : 2.5.2010
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| 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 | jae SHORT .Int40hIsAlreadyInstalled
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| 28 | clc
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| 29 | ret
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| 30 | ALIGN JUMP_ALIGN
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| 31 | .Int40hIsAlreadyInstalled:
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| 32 | stc
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| 33 | ret
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| 34 |
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| 35 |
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| 36 | ;--------------------------------------------------------------------
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| 37 | ; Returns floppy drive type.
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| 38 | ; PC/XT system do not support AH=08h but FLOPPY_TYPE_525_OR_35_DD
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| 39 | ; is still returned for them.
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| 40 | ;
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| 41 | ; FloppyDrive_GetType
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| 42 | ; Parameters:
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| 43 | ; DL: Floppy Drive number
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| 44 | ; Returns:
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| 45 | ; BX: Floppy Drive Type:
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| 46 | ; FLOPPY_TYPE_525_OR_35_DD
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| 47 | ; FLOPPY_TYPE_525_DD
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| 48 | ; FLOPPY_TYPE_525_HD
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| 49 | ; FLOPPY_TYPE_35_DD
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| 50 | ; FLOPPY_TYPE_35_HD
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| 51 | ; FLOPPY_TYPE_35_ED
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| 52 | ; CF: Set if AH=08h not supported (XT systems) or error
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| 53 | ; Cleared if type read correctly (AT systems)
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| 54 | ; Corrupts registers:
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| 55 | ; AX, CX, DX, DI, ES
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| 56 | ;--------------------------------------------------------------------
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| 57 | ALIGN JUMP_ALIGN
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| 58 | FloppyDrive_GetType:
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| 59 | mov ah, 08h ; Get Drive Parameters
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| 60 | xor bx, bx ; FLOPPY_TYPE_525_OR_35_DD when function not supported
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| 61 | int INTV_FLOPPY_FUNC
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| 62 | ret
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| 63 |
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| 64 |
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| 65 | ;--------------------------------------------------------------------
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| 66 | ; Returns number of Floppy Drives in system.
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| 67 | ;
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| 68 | ; FloppyDrive_GetCount
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| 69 | ; Parameters:
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| 70 | ; Nothing
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| 71 | ; Returns:
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| 72 | ; CX: Number of Floppy Drives
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| 73 | ; Corrupts registers:
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| 74 | ; Nothing
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| 75 | ;--------------------------------------------------------------------
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| 76 | ALIGN JUMP_ALIGN
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| 77 | FloppyDrive_GetCount:
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| 78 | push es
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| 79 | call FloppyDrive_GetCountFromBIOS
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| 80 | jnc SHORT .CompareToUserMinimum
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| 81 | call FloppyDrive_GetCountFromBDA
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| 82 | ALIGN JUMP_ALIGN
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| 83 | .CompareToUserMinimum:
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| 84 | MAX_U cl, [cs:ROMVARS.bMinFddCnt]
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| 85 | xor ch, ch
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| 86 | pop es
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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 | ; Reads Floppy Drive Count from BIOS.
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| 92 | ; Does not work on most XT systems. Call FloppyDrive_GetCountFromBDA
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| 93 | ; if this function fails.
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| 94 | ;
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| 95 | ; FloppyDrive_GetCountFromBIOS
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| 96 | ; Parameters:
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| 97 | ; Nothing
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| 98 | ; Returns:
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| 99 | ; CL: Number of Floppy Drives
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| 100 | ; CF: Cleared if successfull
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| 101 | ; Set if BIOS function not supported
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| 102 | ; Corrupts registers:
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| 103 | ; CH, ES
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| 104 | ;--------------------------------------------------------------------
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| 105 | ALIGN JUMP_ALIGN
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| 106 | FloppyDrive_GetCountFromBIOS:
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| 107 | push di
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| 108 | push dx
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| 109 | push bx
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| 110 | push ax
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| 111 |
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| 112 | mov ah, 08h ; Get Drive Parameters
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| 113 | xor dx, dx ; Floppy Drive 00h
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| 114 | int INTV_FLOPPY_FUNC
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| 115 | mov cl, dl ; Number of Floppy Drives to CL
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| 116 |
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| 117 | pop ax
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| 118 | pop bx
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| 119 | pop dx
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| 120 | pop di
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| 121 | ret
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| 122 |
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| 123 |
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| 124 | ;--------------------------------------------------------------------
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| 125 | ; Reads Floppy Drive Count (0...4) from BIOS Data Area.
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| 126 | ; This function should be used only if FloppyDrive_GetCountFromBIOS fails.
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| 127 | ;
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| 128 | ; FloppyDrive_GetCountFromBDA
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| 129 | ; Parameters:
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| 130 | ; Nothing
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| 131 | ; Returns:
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| 132 | ; CL: Number of Floppy Drives
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| 133 | ; Corrupts registers:
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| 134 | ; CH, ES
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| 135 | ;--------------------------------------------------------------------
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| 136 | ALIGN JUMP_ALIGN
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| 137 | FloppyDrive_GetCountFromBDA:
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| 138 | LOAD_BDA_SEGMENT_TO es, cx
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| 139 | mov cl, [es:BDA.wEquipment] ; Load Equipment WORD low byte
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| 140 | mov ch, cl ; Copy it to CH
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| 141 | and cx, 0C001h ; Leave bits 15..14 and 0
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| 142 | eROL_IM ch, 2 ; EW low byte bits 7..6 to 1..0
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| 143 | add cl, ch ; CL = Floppy Drive count
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| 144 | ret
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