TiCPU

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• analogRead resets pinMode to "input"

  @TiCPU started

  • 5 comments
  • 3,633 views

  @Gordon replied
• analogRead resets pinMode to "input"

  in General • 9 years, 1 month

  

  I'm trying to set-up an input_pullup and each time I do an analogRead on it, the pinMode resets from "input_pullup" to standard "input", I'm not sure this has always been to correct behaviour. I'm using the original Espruino board on latest version 1v75.

• Multi-threading?

  @TiCPU started

  • 13 comments
  • 6,673 views

  @Gordon replied
• Problems with JS implementation

  in JavaScript • 10 years, 2 months

  

  For the octal part, 019 gets me an non-octal SyntaxError in Firefox, however, Espruino doesn't handle exceptions at the moment, so I guess either it should stay as-is or output NaN.

  As for the 2 constants, I guess this is a normal behaviour in the case of how floats are implemented on hardware. It can not be more precise than the hardware itself.

• Multi-threading?

  in General • 10 years, 2 months

  

  And here is my final code for my needs, this won't stack overflow:

  nqsort: 425.1626749999999788087 (0.343325)

  // Non-nested quick sort
  Array.prototype.nqsort = function(depth) {
    var pivot, i=0, left, right;
    if (depth === undefined) {
      depth = parseInt(Math.floor(this.length/5), 10);
    }
    var begin = Uint16Array(depth);
    var end = Uint16Array(depth);
  
    begin[0] = 0;
    end[0] = this.length;
  
    while (i >= 0) {
      left = begin[i]; right = end[i]-1;
      if (left < right) {
        pivot = this[left];
        if (i === depth-1) return false;
        while (left < right) {
          while (this[right] >= pivot && left < right) right--;
          if (left < right) this[left++] = this[right];
          while (this[left] <= pivot && left < right) left++;
          if (left < right) this[right--] = this[left];
        }
        this[left] = pivot; begin[i+1] = left+1;
        end[i+1] = end[i]; end[i++] = left;
      } else i--;
    }
    return true;
  };
  Uint16Array.prototype.nqsort = Array.prototype.nqsort;
  

  References: http://alienryderflex.com/quicksort/

• Multi-threading?

  in General • 10 years, 2 months

  

  I tried optimizing the function, removing functions call seem to help quite a bit, and prevent stack overflows just a bit since it is easy to get one.

  qsort: 165526.5649749999865889 (0.398799999995389953255)

  swap and qsort_partition not needed anymore:

  // Quick sort
  Array.prototype.qsort = function (left, right) {
    var pivot, newPivot, pivotVal, tmp;
  
    if (left === undefined) {
      left = 0;
      right = this.length - 1;
    }
  
    if (left < right) {
      pivot = left + Math.ceil((right - left) / 2);
  
      // Partition
      pivotVal = this[pivot];
      newPivot = left;
      this[pivot] = this[right]; this[right] = pivotVal;
      for (var i = left; i < right; i++) {
        if (this[i] < pivotVal) {
          tmp = this[i]; this[newPivot++] = i; this[i] = tmp;
        }
      }
  
      this.qsort(left, newPivot - 1);
      this.qsort(newPivot + 1, right);
    }
  };
  Uint16Array.prototype.qsort = Array.prototype.qsort;
  

• Multi-threading?

  in General • 10 years, 2 months

  

  Attaching did not work, I'll just paste it inline:

  // Useful functions
  Array.prototype.median = function () {
    return this[Math.floor(this.length/2)];
  };
  Uint16Array.prototype.median = Array.prototype.median;
  
  Array.prototype.swap = function (left, right) {
    var tmp = this[left];
    
    this[left] = this[right];
    this[right] = tmp;
    
    return this;
  };
  Uint16Array.prototype.swap = Array.prototype.swap;
  
  Uint16Array.prototype.clear = function () {
    for (var i = 0; i < this.length; i++) this[i] = 0;
  };
  
  // Bubble sort
  Array.prototype.sort = function () {
    var len = this.length - 1;
  
    for (var i = 0; i < len; i++) {
      for (var j = 0, swapping, endIndex = len - i; j < endIndex; j++) {
        if (this[j] > this[j + 1]) {
          swapping = this[j];
          this[j] = this[j + 1];
          this[j + 1] = swapping;
        }
      }
    }
    return this;
  };
  Uint16Array.prototype.sort = Array.prototype.sort;
  
  // Quick sort
  Array.prototype.qsort_partition = function (pivot, left, right) {
    var tmp, storeIndex = left, pivotVal = this[pivot];
  
    this.swap(pivot, right);
    for (var i = left; i < right; i++) {
      if (this[i] < pivotVal) {
        this.swap(i, storeIndex);
        storeIndex++;
      }
    }
    this.swap(right, storeIndex);
  
    return storeIndex;
  };
  Uint16Array.prototype.qsort_partition = Array.prototype.qsort_partition;
  
  Array.prototype.qsort = function (left, right) {
    var pivot, newPivot;
  
    if (left === undefined) {
      left = 0;
      right = this.length - 1;
    }
  
    if (left < right) {
      pivot = left + Math.ceil((right - left) / 2);
      newPivot = this.qsort_partition(pivot, left, right);
      this.qsort(left, newPivot - 1);
      this.qsort(newPivot + 1, right);
    }
  
    return this;
  };
  Uint16Array.prototype.qsort = Array.prototype.qsort;
  
  // Tests
  var tQsort = new Uint16Array([5454,5449,5380,5412,5380,53­66,5344,5395,5398,5424,5422,5473,5420,54­32,5376,5354,5561,5288,5393,5388,5422,54­27,5476,5407,5385,5180,5363,5324,5395,53­93,5410,5405,5349,5361,5385,5412,5373,53­73,5478,5420,5446,5395,5339,5407,5420,53­56,5336,5427,5459,5378,5336,5349,5420,54­05,5434,5383,5446,5422,5349,5329,5405,54­34,5446,5336,5427,5473,5402,5170,5388,54­12,5456,123,456,789]);
  var tBsort = new Uint16Array([5454,5449,5380,5412,5380,53­66,5344,5395,5398,5424,5422,5473,5420,54­32,5376,5354,5561,5288,5393,5388,5422,54­27,5476,5407,5385,5180,5363,5324,5395,53­93,5410,5405,5349,5361,5385,5412,5373,53­73,5478,5420,5446,5395,5339,5407,5420,53­56,5336,5427,5459,5378,5336,5349,5420,54­05,5434,5383,5446,5422,5349,5329,5405,54­34,5446,5336,5427,5473,5402,5170,5388,54­12,5456,123,456,789]);
  
  var qsortTime, bsortTime, startTime = getTime();
  tQsort.qsort();
  qsortTime = getTime();
  tBsort.sort();
  bsortTime = getTime();
  
  print("start: " + startTime);
  print("qsort: " + qsortTime + " (" + (qsortTime-startTime) + ")");
  print("bsort: " + bsortTime + " (" + (bsortTime-qsortTime) + ")");
  

• Multi-threading?

  in General • 10 years, 2 months

  

  I forgot that you would need to instantiate a second parsing tree.

  I attached the tests I made with sorts. Here is the output:

  start: 162142.4207250000035855
  qsort: 162142.9275999999954365 (0.506874999991850927472)
  bsort: 162144.6809749999956693 (1.753375000000232830643)

• Multi-threading?

  in General • 10 years, 2 months

  

  Would it be possible for a function to have a point where it could "yield" the CPU for other functions to execute? I added a quick sort function to Uint16Array which takes about 15 seconds to execute which breaks some timings when setInterval() are too short.

  I take the "yield" expression from Lua which implements multi-threading as coroutines, see: http://lua-users.org/wiki/CoroutinesTuto­rial

• Solar Powered Espruino

  in General • 10 years, 2 months

  

  Thinking about this, is there a way to control when the Bluetooth radio is on? Or is there any Bluetooth LE module available? This is one of the rare thing that my RFduino has better than Espruino at the moment! Those RFduino are very very low power; maximum current is 18mA while transmitting on BLE with ultra low power modes down to 4uA. Not the same speed, features and size but its integrated BLE radio really rocks.