// Float is 32-bit (4 bytes)
function hex2float(num) {
var sign = (num & 0x80000000) ? -1 : 1; // 1 bit. To check the sign bit on most left
var exponent = ((num >> 23) & 0xff) - 127; // 8 bits. 8 right bits. -127 to 128
var mantissa = 1 + ((num & 0x7fffff) / 0x7fffff); // 23 bits
return parseFloat((sign * mantissa * Math.pow(2, exponent)).toFixed(3));
}

// Double is 64-bit (8 bytes)
function hex2double(left, right) {
var sign = (left & 0x80000000) ? -1 : 1; // 1 bit. To check the sign bit on most left
var e = (left >> 52 - 32 & 0x7ff) - 1023
return (left & 0xfffff | 0x100000) * 1.0 / Math.pow(2,52-32) * Math.pow(2, e) + right * 1.0 / Math.pow(2, 52) * Math.pow(2, e)
}

// For UPLINK packets
function Decode(fPort, bytes, variables) {
  // bytes[0] is payload version. Can ignore it
  // To check length: bytes.length > x
  // If > 12 bytes, must set AT+DWELLT=0
  
  // To start from bytes[1]
  // Float (4 bytes)
  var float1=hex2float(bytes[1] << 24 | bytes[2] << 16 | bytes[3] << 8 | bytes[4]);
  
  // Double (8 bytes)
  var left2=bytes[5] << 24 | bytes[6] << 16 | bytes[7] << 8 | bytes[8];
  var right2=bytes[9] << 24 | bytes[10] << 16 | bytes[11] << 8 | bytes[12];
  var double2=hex2double(left2, right2);
  
  // Simple float number (2 bytes), xx.x 
  var simple_float3=(bytes[13] << 8 | bytes[14]) / 10;
  
  // Unsigned integer (2 bytes), xx
  var unsigned_int4=bytes[15] << 8 | bytes[16];
  
  // Unsigned long (4 bytes), xx
  var unsigned_long5=bytes[17] << 24 | bytes[18] << 16 | bytes[19] << 8 | bytes[20];
  
  return {"float1": float1, "double2": double2, "simple_float3": simple_float3,
	"unsigned_int4":unsigned_int4, "unsigned_long5": unsigned_long5};
}