3 ms·

Does anyone have any recs to learn about what goes into a basic BIOS? The TinyBIOS source is super easy to read but I'm looking more for something like xv6 whic

Does anyone have any recs to learn about what goes into a basic BIOS? The TinyBIOS source is super easy to read but I'm looking more for something like xv6 which is both fun to read and also pedagogic (a tall order I'm asking for free, I know ;)

hakfoo 4y ago
There are at least three "real" 8086 BIOSes-- "real" as in they can work on actual hardware rather than just emulators-- available in source form, which might be worth examining. https://www.phatcode.net/downloads.php?id=101 https://www.phatcode.net/downloads.php?id=101 -- this is a respin of code that apparently originated in the 1980s in sketchy Taiwanese clones, so I think some of the docs are reverse engineered http://glabios.org/ http://glabios.org/ is an all-new-still-under-development project, but it works well enough for my hobby usage. https://github.com/skiselev/8088_bios https://github.com/skiselev/8088_bios These are more targeted towards some specific hardware projects (Xi8088/Micro8088) Obviously, being for a simple 8086 mrans they don't have some of the complex chipset config used in a modern PC, and even stuff like "hard disc support" is outsourced (for that, you might consider stuff like the XT-IDE Universal BIOS)
- snvzz 4y ago
  Glabios is GPL3, although unfortunately based upon MASM (non-free and quite old-fashioned assembler). The other two are sketchy and no license (i.e. unusable), respectively.
  - tssva 4y ago
    Sergey's XT BIOS does have a license. It is GPL3. There is no license file in the repo but each source file contains the copyright and license information.
    - snvzz 4y ago
      I see. GPL-3. And it uses NASM, so I'm also happy about it. I guess I now have a large amount of code to read. Oh well.
snvzz 4y ago
IBM's documentation for the original PC includes its BIOS source code. Not sure if in its entirely, or a good portion thereof.

hakfoo 4y ago

There are at least three "real" 8086 BIOSes-- "real" as in they can work on actual hardware rather than just emulators-- available in source form, which might be worth examining. https://www.phatcode.net/downloads.php?id=101 https://www.phatcode.net/downloads.php?id=101 -- this is a respin of code that apparently originated in the 1980s in sketchy Taiwanese clones, so I think some of the docs are reverse engineered http://glabios.org/ http://glabios.org/ is an all-new-still-under-development project, but it works well enough for my hobby usage. https://github.com/skiselev/8088_bios https://github.com/skiselev/8088_bios These are more targeted towards some specific hardware projects (Xi8088/Micro8088) Obviously, being for a simple 8086 mrans they don't have some of the complex chipset config used in a modern PC, and even stuff like "hard disc support" is outsourced (for that, you might consider stuff like the XT-IDE Universal BIOS)

snvzz 4y ago
Glabios is GPL3, although unfortunately based upon MASM (non-free and quite old-fashioned assembler). The other two are sketchy and no license (i.e. unusable), respectively.
- tssva 4y ago
  Sergey's XT BIOS does have a license. It is GPL3. There is no license file in the repo but each source file contains the copyright and license information.
  - snvzz 4y ago
    I see. GPL-3. And it uses NASM, so I'm also happy about it. I guess I now have a large amount of code to read. Oh well.

snvzz 4y ago

IBM's documentation for the original PC includes its BIOS source code. Not sure if in its entirely, or a good portion thereof.