Espruino 2v16 released

I'm pleased to announce Espruino 2v16

This one adds some really decent performance improvements:

Interpreter speed improvements

After some careful analysis of the assembly, I managed to make a few tweaks to the interpreter. It's now around 12% faster, and smaller too.

A simple 'mandelbrot' test that took 6.5s to execute on 2v15 now takes 5.8s on 2v16

Bangle.js

Fixes/Improvements

• Fixed hang at boot that could be caused is Storage was corrupted in just the wrong way
  
• Stopped the user breaking out of flash erase/compact commands - this should really help with corruption issues
  
• Added option in settings to allow for left-handed wearers
  
• Built-in touchscreen calibration in settings app
  
• Compass heading now reported in the correct direction (apps changed to account for this)
  
  

Performance

• Massive Bangle.js 2 graphics fill improvements (6-12x faster)
  
• LCD now updates 'in the background' while JS code is running
  
• Flash erase can use 64k/all clear command to erase blocks much faster
  
• support for Bangle.setUI({remove:...}) - Clocks/Launchers like the defaults that define this and implement it properly can now 'fast switch' to the launcher and back, which makes the experience of using a Bangle much snappier!
  
  

JIT interpreter improved and added to MDBT42Q/Pixl.js/Puck.js/Bangle.js 1 & 2

You can now tag functions with "jit" and they will be jit-compiled on the device. There's a relatively small subset of the language supported so it can't be used for everything, but it can really make a difference in some situations, especially if you just need to toggle some IO or munch through some data:

var data = new Uint8Array(1000);
for (var i=0;i<data.length;i++) data[i]=i;

// Normal JS
t=getTime();data.forEach(function (d) {
  digitalWrite(LED,d&1);
  digitalWrite(LED,d&2);
  digitalWrite(LED,d&4);
  digitalWrite(LED,d&8);
  digitalWrite(LED,d&16);
  digitalWrite(LED,d&32);
  digitalWrite(LED,d&64);
  digitalWrite(LED,d&128);
});print(getTime()-t); // 2.83 sec 2v15,  2.61 sec 2v16

// Compiled server-side with GCC
function writeLEDs(d) {"compiled"
  digitalWrite(LED,d&1);
  digitalWrite(LED,d&2);
  digitalWrite(LED,d&4);
  digitalWrite(LED,d&8);
  digitalWrite(LED,d&16);
  digitalWrite(LED,d&32);
  digitalWrite(LED,d&64);
  digitalWrite(LED,d&128);
}
t=getTime();data.forEach(writeLEDs);print(getTime()-t); // 1.30 sec

// New, JIT
t=getTime();data.forEach(function (d) {"jit"
  digitalWrite(LED,d&1);
  digitalWrite(LED,d&2);
  digitalWrite(LED,d&4);
  digitalWrite(LED,d&8);
  digitalWrite(LED,d&16);
  digitalWrite(LED,d&32);
  digitalWrite(LED,d&64);
  digitalWrite(LED,d&128);
});print(getTime()-t); // 0.95 sec - > 2.5x faster!

It's still early days so your mileage may vary, but it's another useful tool if you just need to output data quick or do some calculations.

Other changes

• Simple arrow functions like () => {...} now use one variable less than before
  
• E.HSBtoRGB can now be called with E.HSBtoRGB(h,s,b,16) to return a 16 bit value suitable for Bangle.js
  
• Many ESP32 Bluetooth LE central mode improvements - ESP32 can now scan and connect to other devices (for example with Nordic UART) using the exact same code/API as the offical Espruino BLE devices
  
  

Puck.js now has a 'minimal' build with more memory dedicated to Flash storage - This strips out the more niche features (like ESP8266 Wifi support) and allows you to use the storage freed for your data - great for data logging. This was released silently in 2v14, but it deserves a mention here!

... and there's more! Check out http://www.espruino.com/ChangeLog for more info!