🚀 go-pugleaf

In article <4rkkhn$54@natasha.rmii.com> underwoe@rmii.com "Edmond" writes:

>Lawrence Kirby <fred@genesis.demon.co.uk> wrote:
>
>>Certainly, they are 32 bit applications even running under DOS (they use
>>32 bit DOS extenders). Only things like disk I/O have o use 16 bit code
>>and CPU speed isn't particularly relevat there since it is waiting for the
>>disk most of the time.
>>
>
>32-bit doesn't mean that you are using a flat memory model.

In theory no. In practice with current OSs and extenders that is
exactly what is means.

> The latter is 
>just as important as using 32-bit registers for data.  Segmented memory 
>causes you to subvert the branch prediction model of the P-PRO which 
>causes all sorts of processor stalls apparently.  

That and register aliasing are the main things that have given the Ppro a
bad name for 16 bit apps. 32 bit code give you more flexibility in the
use of registers and until a 4GB address space ceases to be adequate
code can use a 'small' memory model.

>>>And wait for a 
>>>Pentium Pro built version of Quake for NT 4.0 with Xdirect video and 
>>>sound. 
>>
>>The only reason an NT version would run faster in normal play is if it
>>were able to use some of the features of the graphics/sound cards better.
>>This is relevant but not a 16 vs 32 bit code issue.
>
>Not exactly.  If the drivers and the graphics API are all fully 32-bit, 
>you'll get better performance from the 32-bit versions.  Win95 uses 16-bit 
>graphics (and some video/sound drivers are still 16-bit), so your doomed 
>to slowdom on a Pentium PRO.

Possibly for some of the control functions but those should have
insignificant overhead anyway. Access to the screen memory is 32 bit.
Under DOS I would expect it to deal with VGA modes directly, with
possibly some 16 bit calls for VESA modes.

> WinNT 4.0 would give you much superior 
>graphics performance under the PRO.  

I doubt whether the difference would be noticable, possibly not even
measurable except, as stated above, where it is able to take better
advantage of the graphics/sound card features.

-- 
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Lawrence Kirby | fred@genesis.demon.co.uk
Wilts, England | 70734.126@compuserve.com
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