| 1 | ; File name : AH2h_HRead.asm
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| 2 | ; Project name : IDE BIOS
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| 3 | ; Created date : 27.9.2007
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| 4 | ; Last update : 1.8.2010
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| 5 | ; Author : Tomi Tilli
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| 6 | ; Description : Int 13h function AH=2h, Read Disk Sectors.
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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 | ; Int 13h function AH=2h, Read Disk Sectors.
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| 13 | ;
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| 14 | ; AH2h_HandlerForReadDiskSectors
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| 15 | ; Parameters:
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| 16 | ; AH: Bios function 2h
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| 17 | ; AL: Number of sectors to read (1...255)
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| 18 | ; CH: Cylinder number, bits 7...0
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| 19 | ; CL: Bits 7...6: Cylinder number bits 9 and 8
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| 20 | ; Bits 5...0: Starting sector number (1...63)
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| 21 | ; DH: Starting head number (0...255)
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| 22 | ; DL: Drive number (8xh)
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| 23 | ; ES:BX: Pointer to buffer recieving data
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| 24 | ; Parameters loaded by Int13h_Jump:
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| 25 | ; DS: RAMVARS segment
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| 26 | ; Returns:
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| 27 | ; AH: Int 13h/40h floppy return status
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| 28 | ; AL: Burst error length if AH=11h, undefined otherwise
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| 29 | ; CF: 0 if successfull, 1 if error
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| 30 | ; IF: 1
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| 31 | ; Corrupts registers:
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| 32 | ; Flags
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| 33 | ;--------------------------------------------------------------------
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| 34 | ALIGN JUMP_ALIGN
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| 35 | AH2h_HandlerForReadDiskSectors:
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| 36 | test al, al ; Invalid sector count?
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| 37 | jz SHORT AH2h_ZeroCntErr ; If so, return with error
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| 38 |
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| 39 | ; Save registers
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| 40 | push dx
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| 41 | push cx
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| 42 | push bx
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| 43 | push ax
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| 44 |
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| 45 | ; Select sector or block mode command
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| 46 | call FindDPT_ForDriveNumber ; DS:DI now points to DPT
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| 47 | mov ah, HCMD_READ_SECT ; Load sector mode command
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| 48 | cmp BYTE [di+DPT.bSetBlock], 1 ; Block mode enabled?
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| 49 | jbe SHORT .XferData ; If not, jump to transfer
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| 50 | mov ah, HCMD_READ_MUL ; Load block mode command
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| 51 |
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| 52 | ; Transfer data
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| 53 | ALIGN JUMP_ALIGN
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| 54 | .XferData:
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| 55 | call HCommand_OutputCountAndLCHSandCommand
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| 56 | jc SHORT .Return ; Return if error
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| 57 | call HPIO_ReadBlock ; Read data from IDE-controller
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| 58 | .Return:
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| 59 | jmp Int13h_PopXRegsAndReturn
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| 60 |
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| 61 | ; Invalid sector count (also for AH=3h and AH=4h)
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| 62 | AH2h_ZeroCntErr:
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| 63 | mov ah, RET_HD_INVALID ; Invalid value passed
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| 64 | stc ; Set CF since error
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| 65 | jmp Int13h_StoreErrorCodeToBDAandPopDSDIandReturn
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