[haiku-commits] Re: r38003 -=D=A haiku/trunk/src/system/boot/platform/bios_ia32
- From: François Revol <revol@xxxxxxx>
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Tue, 10 Aug 2010 19:18:54 +0200
Le 10 août 2010 à 18:35, Stephan Assmus a écrit :
> Hi,
>
> On 2010-08-10 at 14:14:48 [+0200], pulkomandy
> <pulkomandy@xxxxxxxxxxxxxxxxx> wrote:
>>> I believe QEMU might use unusual organization on the bits.
>>
>> Some video cards have a "16-bit" mode that is identical to
>> 15-bit with an unused bit (xRRRRRGGGGGBBBBB), others have
>> one extra green bit (RRRRRGGGGGGBBBBB). The unused bit may
>> also be elsewhere.
>
> If I am not mistaken, a 15 bit mode *always* has an unused bit somewhere.
> Didn't know it could be at different places, but it would surely explain
> unexpected weirdness. :-)
It can change with endianness and all...
It seems the VESA mode descriptors have info on the bit order, with a bitmask
and shift for all components, which can describe all possible ways. Maybe QEMU
uses unusual ordering and we ignore it.
François.
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