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Index > OS Construction > Will bios call change segment registers?

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l4m2



Joined: 15 Jan 2015
Posts: 661
l4m2
If they change, even pushed and later poped back, their meanings may be different
Post 19 Jan 2021, 02:29
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 18115
Location: In your JS exploiting you and your system
revolution
l4m2 wrote:
Will bios call change segment registers?
No.
Post 19 Jan 2021, 04:47
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sinsi



Joined: 10 Aug 2007
Posts: 729
Location: Adelaide
sinsi
Yes, if a BIOS function returns values in a segment register Smile
IIRC some BIOSes used "unreal mode" for the move extended memory function.
Post 19 Jan 2021, 05:11
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bitshifter



Joined: 04 Dec 2007
Posts: 786
Location: Massachusetts, USA
bitshifter
my 512 byte multi tasking micro kernel exposed bug where bios was not restoring my DS reg, it was leaving it at 0x40 BIOS data segment area

_________________
Coding a 3D game engine with fasm is like trying to eat an elephant,
you just have to keep focused and take it one 'byte' at a time.


Last edited by bitshifter on 18 Feb 2021, 12:23; edited 1 time in total
Post 16 Feb 2021, 09:58
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 18115
Location: In your JS exploiting you and your system
revolution
bitshifter wrote:
... bug where bios was not restoring my DS reg, it was leaving it at 0x40 BIOS data segment area
Which BIOS? Which function?
Post 17 Feb 2021, 06:08
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bitshifter



Joined: 04 Dec 2007
Posts: 786
Location: Massachusetts, USA
bitshifter

_________________
Coding a 3D game engine with fasm is like trying to eat an elephant,
you just have to keep focused and take it one 'byte' at a time.
Post 17 Feb 2021, 16:18
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