Teensy 3.2/3.6 using arm_neon.h

[GinDiamond]

Hello,

I've been poking around the libraries and hardware features of the teensy, and found that there's supposedly SIMD support https://forum.pjrc.com/threads/31285-SIMD-instructions-with-Teensy.

I looked deeper into this, and found that there's a library in the teensy folder called "arm_neon.h". I tried including it in a bare project but I'm getting this error upon compilation:

#include <arm_math.h>
#include <arm_neon.h>

int32x2_t i;

void setup() {

}

void loop() {
  
}

In file included from C:\Users\user\Documents\Arduino\teensy_math\teensy_math.ino:7:0:

c:\program files (x86)\arduino\hardware\tools\arm\lib\gcc\arm-none-eabi\5.4.1\include\arm_neon.h:31:2: error: #error You must enable NEON instructions (e.g. -mfloat-abi=softfp -mfpu=neon) to use arm_neon.h

 #error You must enable NEON instructions (e.g. -mfloat-abi=softfp -mfpu=neon) to use arm_neon.h

  ^

teensy_math:9: error: 'int32x2_t' does not name a type
 int32x2_t i;

 ^

'int32x2_t' does not name a type

How do I enable neon? Do I need to edit the build flags? If so, how do I do this?

 

[Frank B]

ARM NEON is single instruction - multiple data ("SIMD") for the ARM Cortex-A Series and R52.
Teensy 3.x is Cortex-M and does not support NEON. But it can do SIMD, with its DSP-Extensions. The audio-library for example uses these instructions.

 

[GinDiamond]

Ah, I see. My hopes are slightly dashed.

I was hoping for SIMD instructions that can do vector addition/multiplication like neon. I'll check out the audio library later tonight and see what I find.

Thanks!

 

[Frank B]

This is a better resource: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.100166_0001_00_en/ric1417449098079.html

 

[GinDiamond]

Thank you so much! Exactly what I was trying to find.