Any beginner-level tutorials on NEON assembly programming?

[Andrei Krishkevich]

Hello all,

I'm stuck implementing a very CPU-hungry DSP algorithm and compiler
flags for NEON usage do improve performance, but I think I actually
have to write some Assembly to squeeze all performance I can out of
the processor and call that my benchmark.

I'm not particularly versed in Assembly, and most of the documentation
available online concerning programming ARM processors is given in
context of the RVCT compiler (produced by ARM). As far as I
understand, syntax and compiler flags differ for RVCT and GCC (Gas),
so I have no solid starting point for learning about this stuff.

Assembly language itself is not the big deal for me, I had to learn a
ton of new languages over the years; it's the specific context of ARM
NEON Assembly code to fed into a GNU assembler that seems to be the
nearly undocumented, vague portion of the learning. Are there any good
tutorials out there? If not specifically on this topic, where do I
start?

Cheers! = )

[mic _]

This page lists the expected instruction format for each NEON intrinsic: http://gcc.gnu.org/onlinedocs/gcc/ARM-NEON-Intrinsics.html

/Michael

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[Dave Butcher]

Hi,

These might be useful:

http://blogs.arm.com/software-enablement/161-coding-for-neon-part-1-load-and-stores/
http://blogs.arm.com/software-enablement/196-coding-for-neon-part-2-dealing-with-leftovers/
http://blogs.arm.com/software-enablement/241-coding-for-neon-part-3-matrix-multiplication/
http://blogs.arm.com/software-enablement/277-coding-for-neon-part-4-shifting-left-and-right/

Dave.

[Andrei Krishkevich]

Thanks. These are all very useful.

On Jun 21, 5:03 am, Dave Butcher <djb....@googlemail.com> wrote:
> Hi,
>
> These might be useful:
>

> http://blogs.arm.com/software-enablement/161-coding-for-neon-part-1-l...http://blogs.arm.com/software-enablement/196-coding-for-neon-part-2-d...http://blogs.arm.com/software-enablement/241-coding-for-neon-part-3-m...http://blogs.arm.com/software-enablement/277-coding-for-neon-part-4-s...
>
>   Dave.

[Kirill Kornyakov]

And here is our list:

ARM/NEON optimization¶

• ARM GCC compiler options: http://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html
  
• Full GCC intrinsics reference: http://gcc.gnu.org/onlinedocs/gcc/ARM-NEON-Intrinsics.html
  • arm_neon.h http://code.google.com/p/leaflabs/source/browse/trunk/maple/build/linux/dist/tools/arm/lib/gcc/arm-none-eabi/4.4.1/include/arm_neon.h?r=86
• Nice manual full of links: http://pixhawk.ethz.ch/wiki/omap/optimization/arm_cortex_a8
  • Nice whitepaper with beginner and advanced tips: http://pixhawk.ethz.ch/wiki/_media/software/optimization/neon_support_in_the_arm_compiler.pdf
• NEON and VFP Programming - instructions reference
• gcc builtins - prefetch, etc

• Instruction Set Quick Reference Cards
  • Thumb 16-bit
  • ARM and Thumb-2
  • Vector Floating Point

• Instructions timings
  • Cycle timings of integer instructions on Cortex-A9 processors
  • Floating-Point Unit Definitions of throughput and latency
  • Cortex-A9 NEON Media Processing Engine Instruction timing tables

• http://www.shervinemami.info/armAssembly.html

• Coding for NEON - Part 1: Load and Stores
• Coding for NEON - Part 2: Dealing With Leftovers
• Coding for NEON - Part 3: Matrix Multiplication
• Coding for NEON - Part 4: Shifting Left and Right

• Condition Codes 1: Condition Flags and Codes
• Condition Codes 2: Conditional Execution
• Condition Codes 3: Conditional Execution in Thumb-2
• Condition Codes 4: Floating-Point Comparisons Using VFP

[Thimmarayaswamy Krishnappa]

Updated links on ARM NEON Basic Tutorials:

https://community.arm.com/groups/android-community/blog/2015/03/27/arm-neon-programming-quick-reference
https://community.arm.com/groups/processors/blog/2010/03/17/coding-for-neon--part-1-load-and-stores

https://community.arm.com/groups/processors/blog/2010/05/10/coding-for-neon--part-2-dealing-with-leftovers

https://community.arm.com/groups/processors/blog/2010/06/28/coding-for-neon--part-3-matrix-multiplication

https://community.arm.com/groups/processors/blog/2010/09/01/coding-for-neon--part-4-shifting-left-and-right

https://community.arm.com/groups/processors/blog/2012/03/13/coding-for-neon--part-5-rearranging-vectors