| 1 | ; $Id: pcibio32.asm 96407 2022-08-22 17:43:14Z vboxsync $
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| 2 | ;; @file
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| 3 | ; BIOS32 service directory and 32-bit PCI BIOS entry point
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 2006-2022 Oracle and/or its affiliates.
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| 8 | ;
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| 9 | ; This file is part of VirtualBox base platform packages, as
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| 10 | ; available from https://www.virtualbox.org.
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| 11 | ;
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| 12 | ; This program is free software; you can redistribute it and/or
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| 13 | ; modify it under the terms of the GNU General Public License
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| 14 | ; as published by the Free Software Foundation, in version 3 of the
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| 15 | ; License.
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| 16 | ;
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| 17 | ; This program is distributed in the hope that it will be useful, but
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| 18 | ; WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | ; General Public License for more details.
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| 21 | ;
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| 22 | ; You should have received a copy of the GNU General Public License
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| 23 | ; along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | ;
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| 25 | ; SPDX-License-Identifier: GPL-3.0-only
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| 26 | ; --------------------------------------------------------------------
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| 27 |
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| 28 |
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| 29 | ; Public symbols for debugging only
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| 30 | public pcibios32_entry
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| 31 | public bios32_service
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| 32 |
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| 33 | ; The BIOS32 service directory header must be located in the E0000h-FFFF0h
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| 34 | ; range on a paragraph boundary. Note that the actual 32-bit code need not
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| 35 | ; be located below 1MB at all.
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| 36 |
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| 37 | _DATA segment public 'DATA'
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| 38 |
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| 39 | align 16
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| 40 | bios32_directory:
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| 41 | db '_32_' ; ASCII signature
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| 42 | dw bios32_service ; Entry point address...
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| 43 | dw 000Fh ; ...hardcoded to F000 segment
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| 44 | db 0 ; Revision
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| 45 | db 1 ; Length in paras - must be 1
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| 46 | db 0 ; Checksum calculated later
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| 47 | db 5 dup(0) ; Unused, must be zero
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| 48 |
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| 49 | _DATA ends
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| 50 |
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| 51 | .386
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| 52 |
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| 53 | extrn _pci32_function:near
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| 54 |
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| 55 | BIOS32 segment public 'CODE' use32
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| 56 |
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| 57 | ;
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| 58 | ; The BIOS32 Service Directory - must be less than 4K in size (easy!).
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| 59 | ;
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| 60 | bios32_service proc far
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| 61 |
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| 62 | pushfd
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| 63 |
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| 64 | cmp bl, 0 ; Only function 0 supported
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| 65 | jnz b32_bad_func
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| 66 |
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| 67 | cmp eax, 'ICP$' ; "$PCI"
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| 68 | mov al, 80h ; Unknown service
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| 69 | jnz b32_done
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| 70 |
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| 71 | mov ebx, 000f0000h ; Base address (linear)
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| 72 | mov ecx, 0f000h ; Length of service
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| 73 | mov edx, pcibios32_entry ; Entry point offset from base
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| 74 | xor al, al ; Indicate success
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| 75 | b32_done:
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| 76 | popfd
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| 77 | retf
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| 78 |
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| 79 | b32_bad_func:
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| 80 | mov al, 81h ; Unsupported function
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| 81 | jmp b32_done
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| 82 |
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| 83 | bios32_service endp
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| 84 |
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| 85 | ;
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| 86 | ; The 32-bit PCI BIOS entry point - simply calls into C code.
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| 87 | ;
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| 88 | pcibios32_entry proc far
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| 89 |
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| 90 | pushfd ; Preserve flags
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| 91 | cld ; Just in case...
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| 92 |
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| 93 | push es ; Call into C implementation
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| 94 | pushad
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| 95 | call _pci32_function
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| 96 | popad
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| 97 | pop es
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| 98 |
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| 99 | popfd ; Restore flags and return
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| 100 | retf
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| 101 |
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| 102 | pcibios32_entry endp
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| 103 |
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| 104 |
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| 105 | BIOS32 ends
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| 106 |
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| 107 | end
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| 108 |
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