| 1 | ; File name : AH2h_HRead.asm
|
|---|
| 2 | ; Project name : IDE BIOS
|
|---|
| 3 | ; Created date : 27.9.2007
|
|---|
| 4 | ; Last update : 12.4.2010
|
|---|
| 5 | ; Author : Tomi Tilli
|
|---|
| 6 | ; Description : Int 13h function AH=2h, Read Disk Sectors.
|
|---|
| 7 |
|
|---|
| 8 | ; Section containing code
|
|---|
| 9 | SECTION .text
|
|---|
| 10 |
|
|---|
| 11 | ;--------------------------------------------------------------------
|
|---|
| 12 | ; Int 13h function AH=2h, Read Disk Sectors.
|
|---|
| 13 | ;
|
|---|
| 14 | ; AH2h_HandlerForReadDiskSectors
|
|---|
| 15 | ; Parameters:
|
|---|
| 16 | ; AH: Bios function 2h
|
|---|
| 17 | ; AL: Number of sectors to read (1...255)
|
|---|
| 18 | ; CH: Cylinder number, bits 7...0
|
|---|
| 19 | ; CL: Bits 7...6: Cylinder number bits 9 and 8
|
|---|
| 20 | ; Bits 5...0: Starting sector number (1...63)
|
|---|
| 21 | ; DH: Starting head number (0...255)
|
|---|
| 22 | ; DL: Drive number (8xh)
|
|---|
| 23 | ; ES:BX: Pointer to buffer recieving data
|
|---|
| 24 | ; Parameters loaded by Int13h_Jump:
|
|---|
| 25 | ; DS: RAMVARS segment
|
|---|
| 26 | ; Returns:
|
|---|
| 27 | ; AH: Int 13h/40h floppy return status
|
|---|
| 28 | ; AL: Burst error length if AH=11h, undefined otherwise
|
|---|
| 29 | ; CF: 0 if successfull, 1 if error
|
|---|
| 30 | ; IF: 1
|
|---|
| 31 | ; Corrupts registers:
|
|---|
| 32 | ; Flags
|
|---|
| 33 | ;--------------------------------------------------------------------
|
|---|
| 34 | ALIGN JUMP_ALIGN
|
|---|
| 35 | AH2h_HandlerForReadDiskSectors:
|
|---|
| 36 | test al, al ; Invalid sector count?
|
|---|
| 37 | jz SHORT AH2h_ZeroCntErr ; If so, return with error
|
|---|
| 38 |
|
|---|
| 39 | ; Save registers
|
|---|
| 40 | push dx
|
|---|
| 41 | push cx
|
|---|
| 42 | push bx
|
|---|
| 43 | push ax
|
|---|
| 44 |
|
|---|
| 45 | ; Select sector or block mode command
|
|---|
| 46 | call FindDPT_ForDriveNumber ; DS:DI now points to DPT
|
|---|
| 47 | mov ah, HCMD_READ_SECT ; Load sector mode command
|
|---|
| 48 | cmp BYTE [di+DPT.bSetBlock], 1 ; Block mode enabled?
|
|---|
| 49 | jbe SHORT .XferData ; If not, jump to transfer
|
|---|
| 50 | mov ah, HCMD_READ_MUL ; Load block mode command
|
|---|
| 51 |
|
|---|
| 52 | ; Transfer data
|
|---|
| 53 | ALIGN JUMP_ALIGN
|
|---|
| 54 | .XferData:
|
|---|
| 55 | call HCommand_OutputCountAndLCHSandCommand
|
|---|
| 56 | jc SHORT .Return ; Return if error
|
|---|
| 57 | call HPIO_ReadBlock ; Read data from IDE-controller
|
|---|
| 58 | .Return:
|
|---|
| 59 | jmp Int13h_PopXRegsAndReturn
|
|---|
| 60 |
|
|---|
| 61 | ; Invalid sector count (also for AH=3h and AH=4h)
|
|---|
| 62 | AH2h_ZeroCntErr:
|
|---|
| 63 | mov ah, RET_HD_INVALID ; Invalid value passed
|
|---|
| 64 | stc ; Set CF since error
|
|---|
| 65 | jmp Int13h_PopDiDsAndReturn
|
|---|
