[cairo] Regarding Cairo Optimization for ARM PXA320

Sandeep Agrawal sandeep.a at samsung.com
Sun Oct 28 22:01:24 PDT 2007


Actually I am unable to generate profiling data because of certain problems
with the platform I am working on. I don't have permissions to create a new
device and so opcontrol --init fails.

I am new to the text rendering field. Since Monahans does not have an FPU, I
made the assumption that the affine transformations happening in floating
point may be optimized to work in fixed point. Am I wrong in my assumption?

If so can you please give some hints as to where I can perform
optimizations? I am sure that it would be possible to do some processor
specific optimizations as well as Cairo has been written to cater to a large

Sandeep Agrawal,
Wireless Terminal Division,
Samsung India Software Operations.

-----Original Message-----
From: Dan Amelang [mailto:daniel.amelang at gmail.com] 
Sent: Saturday, October 27, 2007 12:46 AM
To: Sandeep Agrawal
Cc: cairo at cairographics.org
Subject: Re: [cairo] Regarding Cairo Optimization for ARM PXA320

On 10/26/07, Sandeep Agrawal <sandeep.a at samsung.com> wrote:
> I am currently optimizing text rendering in Cairo for the PXA320 Monahans
> processor.
> I just want to know that is it possible to convert the double computations
> (specifically affine) to 16.16 or 26.6 fixed point format (any chance of
> overflow or precision loss?)

Yes, there is a chance of overflow and precision loss.

> or do I have to go with processor specific
> assembly optimizations?

I don't see how this is an either/or situation. How did converting
doubles to fixed-point and using assembly optimizations become your
two options for text rendering improvement?

I assume that your profiles show that floating-point emulation is the
bottleneck? Can you share with us your data?


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