[594] | 1 | ; Project name : XTIDE Universal BIOS |
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| 2 | ; Description : Int 13h handler that is used by MODULE_MFM_COMPATIBILITY. |
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[596] | 3 | ; It is placed between XUB Int 13h handler and system INT 13h handler |
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| 4 | ; to hide XUB from MFM controllers whose BIOS assumes they handle |
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[594] | 5 | ; all hard drives on the system. |
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| 6 | |
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| 7 | ; |
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| 8 | ; XTIDE Universal BIOS and Associated Tools |
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| 9 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team. |
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| 10 | ; |
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| 11 | ; This program is free software; you can redistribute it and/or modify |
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| 12 | ; it under the terms of the GNU General Public License as published by |
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| 13 | ; the Free Software Foundation; either version 2 of the License, or |
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| 14 | ; (at your option) any later version. |
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| 15 | ; |
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| 16 | ; This program is distributed in the hope that it will be useful, |
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| 17 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 18 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 19 | ; GNU General Public License for more details. |
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| 20 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
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| 21 | ; |
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| 22 | |
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| 23 | ; Section containing code |
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| 24 | SECTION .text |
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| 25 | |
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| 26 | |
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| 27 | ;-------------------------------------------------------------------- |
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| 28 | ; Int 13h software interrupt handler for MFM compatibility. |
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| 29 | ; |
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[596] | 30 | ; Some MFM controllers require that BDA drive count is what they have set. |
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[594] | 31 | ; The purpose for this handler is to restore BDA drive count to what MFM controller |
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| 32 | ; expects and then call MFM controller INT 13h. |
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| 33 | ; |
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| 34 | ; Int13hMFMcompatibilityHandler |
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| 35 | ; Parameters: |
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| 36 | ; Any INT 13h function and parameters |
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| 37 | ;-------------------------------------------------------------------- |
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| 38 | ALIGN JUMP_ALIGN |
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| 39 | Int13hMFMcompatibilityHandler: |
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| 40 | eENTER 6, 0 |
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| 41 | push es |
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| 42 | push ds |
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| 43 | push di |
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| 44 | |
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| 45 | LOAD_BDA_SEGMENT_TO es, di |
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| 46 | call RamVars_GetSegmentToDS |
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| 47 | |
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| 48 | ; Remove our drives from BDA drive count |
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| 49 | push ax |
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| 50 | mov al, [RAMVARS.bDrvCnt] |
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| 51 | mov [bp-2], al ; Store our drive count for later use |
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| 52 | sub [es:HDBDA.bHDCount], al |
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| 53 | pop ax |
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| 54 | |
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| 55 | ; Copy MFM controller INT 13h address to stack |
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| 56 | les di, [RAMVARS.fpMFMint13h] |
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| 57 | mov [bp-4], es |
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| 58 | mov [bp-6], di |
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| 59 | |
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| 60 | ; Restore registers so we can call MFM int 13h |
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| 61 | pop di |
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| 62 | pop ds |
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| 63 | pop es |
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| 64 | |
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| 65 | pushf ; Push flags to simulate INT |
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[596] | 66 | call FAR [bp-6] |
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[594] | 67 | |
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| 68 | ; Now we can restore BDA drive count |
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| 69 | push ds |
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| 70 | push ax |
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| 71 | lahf ; Get return flags to AH |
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| 72 | mov [bp-12], ah ; Store return flags to be popped by iret |
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| 73 | LOAD_BDA_SEGMENT_TO ds, ax |
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| 74 | mov al, [bp-2] |
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| 75 | add [HDBDA.bHDCount], al |
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| 76 | pop ax |
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| 77 | pop ds |
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| 78 | |
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| 79 | ; Return from this handler |
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| 80 | eLEAVE |
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| 81 | iret |
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