1 | ; Project name : XTIDE Universal BIOS
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2 | ; Description : Int 13h function AH=Ch, Seek.
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3 |
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4 | ; Section containing code
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5 | SECTION .text
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6 |
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7 | ;--------------------------------------------------------------------
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8 | ; Int 13h function AH=Ch, Seek.
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9 | ;
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10 | ; AHCh_HandlerForSeek
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11 | ; Parameters:
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12 | ; AH: Bios function Ch
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13 | ; CH: Cylinder number, bits 7...0
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14 | ; CL: Bits 7...6: Cylinder number bits 9 and 8
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15 | ; Bits 5...0: Starting sector number (1...63)
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16 | ; DH: Starting head number (0...255)
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17 | ; DL: Drive number
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18 | ; Parameters loaded by Int13h_Jump:
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19 | ; DS: RAMVARS segment
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20 | ; Returns:
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21 | ; AH: BIOS Error code
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22 | ; CF: 0 if succesfull, 1 if error
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23 | ; IF: 1
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24 | ; Corrupts registers:
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25 | ; Flags
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26 | ;--------------------------------------------------------------------
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27 | ALIGN JUMP_ALIGN
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28 | AHCh_HandlerForSeek:
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29 | push dx
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30 | push cx
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31 | push bx
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32 | push ax
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33 | %ifndef USE_186
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34 | call AHCh_SeekToCylinder
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35 | jmp Int13h_PopXRegsAndReturn
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36 | %else
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37 | push Int13h_PopXRegsAndReturn
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38 | ; Fall through to AHCh_SeekToCylinder
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39 | %endif
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40 |
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41 |
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42 | ;--------------------------------------------------------------------
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43 | ; Seeks to a cylinder.
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44 | ;
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45 | ; AHCh_SeekToCylinder
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46 | ; Parameters:
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47 | ; CH: Cylinder number, bits 7...0
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48 | ; CL: Bits 7...6: Cylinder number bits 9 and 8
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49 | ; Bits 5...0: Starting sector number (1...63)
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50 | ; DH: Starting head number (0...255)
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51 | ; DL: Drive Number
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52 | ; DS: RAMVARS segment
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53 | ; Returns:
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54 | ; DS:DI: Ptr to DPT
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55 | ; AH: BIOS Error code
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56 | ; CF: 0 if succesfull, 1 if error
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57 | ; Corrupts registers:
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58 | ; AL, BX, CX, DX
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59 | ;--------------------------------------------------------------------
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60 | ALIGN JUMP_ALIGN
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61 | AHCh_SeekToCylinder:
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62 | call FindDPT_ForDriveNumber ; DS:DI now points to DPT
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63 | mov ax, HCMD_SEEK<<8 ; Load cmd to AH, AL=zero sector cnt
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64 | call HCommand_OutputCountAndLCHSandCommand
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65 | jc SHORT .Return ; Return if error
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66 | mov bx, di ; DS:BX now points to DPT
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67 | jmp HStatus_WaitIrqOrRdy ; Wait for IRQ or RDY
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68 | .Return:
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69 | ret
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