BIOS32: Difference between revisions
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Added structure for Service Directory Header |
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=== Interface === |
=== Interface === |
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==== Locating ==== |
==== Locating ==== |
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The BIOS32 ''Service Directory'' is located on a paragraph (16 Byte) boundary in the physical memory region 0xE0000-0xFFFFF. |
The BIOS32 ''Service Directory'' Header is located on a paragraph (16 Byte) boundary in the physical memory region 0xE0000-0xFFFFF. |
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It starts with a 4 byte signature of "_32_" (0x5F32335F) |
It starts with a 4 byte signature of "_32_" (0x5F32335F) |
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==== Structure ==== |
==== Structure ==== |
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{{ |
{{In Progress}} |
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{| {{wikitable}} |
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|+<b>Service Directory Header</b> |
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|<b>Offset || Size || Name || Description</b> |
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|0 || 4 bytes || Signature || ASCII signature "_32_" (0x5F32335F) |
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|4 || 4 bytes || Entry Point || 32 bit physical address (not CS:IP) of BIOS32 calling interface entry point. |
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|8 || 1 byte || Revision || Revision of BIOS32. Current 0h |
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|9 || 1 byte || Length || Length of structure, in paragraphs |
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|10 || 1 byte || Checksum || A summation checksum (1 byte granularity) |
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|11 || 5 bytes || Reserved || Reserved for future use, should be 0. |
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== See Also == |
== See Also == |
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=== On the Wiki === |
=== On the Wiki === |
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Revision as of 15:38, 26 August 2014
BIOS32
Introduction
BIOS32 is a method for calling BIOS services directly from 32 bit Protected Mode. It is mainly used for PNP and PCI services.
Interface
Locating
The BIOS32 Service Directory Header is located on a paragraph (16 Byte) boundary in the physical memory region 0xE0000-0xFFFFF. It starts with a 4 byte signature of "_32_" (0x5F32335F)
Structure
This page is a work in progress.
This page may thus be incomplete. Its content may be changed in the near future.
| Offset | Size | Name | Description |
| 0 | 4 bytes | Signature | ASCII signature "_32_" (0x5F32335F) |
| 4 | 4 bytes | Entry Point | 32 bit physical address (not CS:IP) of BIOS32 calling interface entry point. |
| 8 | 1 byte | Revision | Revision of BIOS32. Current 0h |
| 9 | 1 byte | Length | Length of structure, in paragraphs |
| 10 | 1 byte | Checksum | A summation checksum (1 byte granularity) |
| 11 | 5 bytes | Reserved | Reserved for future use, should be 0. |