[squeak-dev] Building a linux/Pi library to call via FFI

tim Rowledge tim at rowledge.org
Fri Sep 11 01:55:55 UTC 2015


On 10-09-2015, at 12:33 PM, Eliot Miranda <eliot.miranda at gmail.com> wrote:
> But I think I may re-do it as a plugin today, not least because it seems that the ARM ffi interface has a problem with returning floats; they come back as Character null. I may not be a great IEEE floating point standard expert but that doesn’t seem quite right.
> 
> I'm sure this can be fixed.  Have you talked to Doug McPherson?

Yup. 

And after much head-scratching because I’ve completely forgotten how plugin building works, I finally have a plugin that takes 9 float values, does unspeakable things to them and spits out a four float quaternion answer. On a Pi2 it test at ~ 8 micro-sec per call, which isn’t bad for 270+ floating point operations including 150 divides. The next fun is feeding live IMU data to it and finding away to display something meaningful as a result.


tim
--
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Strange OpCodes: BOMB: Burn Out Memory Banks




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