* [9fans] Nix/regen: multiboot flags
@ 2025-01-28 11:39 tlaronde
2025-01-28 15:30 ` Ron Minnich
2025-01-28 15:45 ` Paul Lalonde
0 siblings, 2 replies; 4+ messages in thread
From: tlaronde @ 2025-01-28 11:39 UTC (permalink / raw)
To: 9fans
In l32p.s, the multiboot flags in the the mbi are set as
$0x00010007
but I don't find flags definitions relative to the higher word,
neither in the multiboot v1 spec, nor in the enum in multiboot.c. They
are all limited to the two lowest bytes.
What is the purpose of the:
$0x00010007
^
Typo?
--
Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
http://www.kergis.com/
http://kertex.kergis.com/
Key fingerprint = 0FF7 E906 FBAF FE95 FD89 250D 52B1 AE95 6006 F40C
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [9fans] Nix/regen: multiboot flags
2025-01-28 11:39 [9fans] Nix/regen: multiboot flags tlaronde
@ 2025-01-28 15:30 ` Ron Minnich
2025-01-28 15:45 ` Paul Lalonde
1 sibling, 0 replies; 4+ messages in thread
From: Ron Minnich @ 2025-01-28 15:30 UTC (permalink / raw)
To: 9fans
all that does is set the lowest two bytes, which is fine.
On Tue, Jan 28, 2025 at 6:09 AM <tlaronde@kergis.com> wrote:
>
> In l32p.s, the multiboot flags in the the mbi are set as
>
> $0x00010007
>
> but I don't find flags definitions relative to the higher word,
> neither in the multiboot v1 spec, nor in the enum in multiboot.c. They
> are all limited to the two lowest bytes.
>
> What is the purpose of the:
>
> $0x00010007
> ^
>
> Typo?
> --
> Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
> http://www.kergis.com/
> http://kertex.kergis.com/
> Key fingerprint = 0FF7 E906 FBAF FE95 FD89 250D 52B1 AE95 6006 F40C
------------------------------------------
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [9fans] Nix/regen: multiboot flags
2025-01-28 11:39 [9fans] Nix/regen: multiboot flags tlaronde
2025-01-28 15:30 ` Ron Minnich
@ 2025-01-28 15:45 ` Paul Lalonde
2025-01-28 17:08 ` tlaronde
1 sibling, 1 reply; 4+ messages in thread
From: Paul Lalonde @ 2025-01-28 15:45 UTC (permalink / raw)
To: 9fans
[-- Attachment #1: Type: text/plain, Size: 1285 bytes --]
The multiboot specification says: If bit 16 in the ‘flags’ word is set,
then the fields at offsets 12-28 in the Multiboot header are valid, and the
boot loader should use them instead of the fields in the actual executable
header to calculate where to load the OS image.
I believe they are valid in this case. These include the load address for
the kernel and the bit depth of the display, found at l32p.s:37,44
Paul
On Tue, Jan 28, 2025 at 6:09 AM <tlaronde@kergis.com> wrote:
> In l32p.s, the multiboot flags in the the mbi are set as
>
> $0x00010007
>
> but I don't find flags definitions relative to the higher word,
> neither in the multiboot v1 spec, nor in the enum in multiboot.c. They
> are all limited to the two lowest bytes.
>
> What is the purpose of the:
>
> $0x00010007
> ^
>
> Typo?
> --
> Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
> http://www.kergis.com/
> http://kertex.kergis.com/
> Key fingerprint = 0FF7 E906 FBAF FE95 FD89 250D 52B1 AE95 6006 F40C
------------------------------------------
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [9fans] Nix/regen: multiboot flags
2025-01-28 15:45 ` Paul Lalonde
@ 2025-01-28 17:08 ` tlaronde
0 siblings, 0 replies; 4+ messages in thread
From: tlaronde @ 2025-01-28 17:08 UTC (permalink / raw)
To: 9fans
On Tue, Jan 28, 2025 at 07:45:02AM -0800, Paul Lalonde wrote:
> The multiboot specification says: If bit 16 in the ?flags? word is set,
> then the fields at offsets 12-28 in the Multiboot header are valid, and the
> boot loader should use them instead of the fields in the actual executable
> header to calculate where to load the OS image.
>
> I believe they are valid in this case. These include the load address for
> the kernel and the bit depth of the display, found at l32p.s:37,44
>
Thanks for the explanations!
> On Tue, Jan 28, 2025 at 6:09?AM <tlaronde@kergis.com> wrote:
>
> > In l32p.s, the multiboot flags in the the mbi are set as
> >
> > $0x00010007
> >
> > but I don't find flags definitions relative to the higher word,
> > neither in the multiboot v1 spec, nor in the enum in multiboot.c. They
> > are all limited to the two lowest bytes.
> >
> > What is the purpose of the:
> >
> > $0x00010007
> > ^
> >
> > Typo?
> > --
> > Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
> > http://www.kergis.com/
> > http://kertex.kergis.com/
> > Key fingerprint = 0FF7 E906 FBAF FE95 FD89 250D 52B1 AE95 6006 F40C
--
Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
http://www.kergis.com/
http://kertex.kergis.com/
Key fingerprint = 0FF7 E906 FBAF FE95 FD89 250D 52B1 AE95 6006 F40C
------------------------------------------
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2025-01-28 11:39 [9fans] Nix/regen: multiboot flags tlaronde
2025-01-28 15:30 ` Ron Minnich
2025-01-28 15:45 ` Paul Lalonde
2025-01-28 17:08 ` tlaronde
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