// shift right fourteen places
// uses byte pointers to long integers.

// starting value 0x7dedbeef should become 0x1f7b6;
// starting value 0x7ff02468 should become 0x1ffc0;

long source = 0x7ff02468;
//long source = 0x7dedbeef;
long destn = 0;
long sPad = 0;

//
// byte pointers to low order byte of source,
// destination and scratchpad.
// byte pointer+1 is next byte
// and so on.
byte *src = (byte*)(&source);
byte *dst = (byte*)(&destn);
byte *scrPad = (byte*)(&sPad);

void setup() {
  Serial.begin(115200);
  Serial.print(source, HEX);
  Serial.print(" becomes ");
  // this sequence takes appprox. ?? cycles
  // wipe low eight bits
  /*scrPad[0] = src[1];
    scrPad[1] = src[2];
    scrPad[2] = src[3];
  */
  for (byte i = 0; i < 3; i++) {
    scrPad[i] = src[i + 1];
  }

  // multiplying by four left shifts two bits, the upper
  // bytes are used as the result
  // this is faster than shifting right six bits
  sPad = sPad * 4; // asm - generates a sequence of four adds to accomplish
  // a single shift and the sequence is executed two times

  //Serial.println(sPad, HEX);
  // copy remaining three upper bytes to low three bytes of destn
  dst[0] = scrPad[1];
  dst[1] = scrPad[2];
  dst[2] = scrPad[3];
  Serial.println(destn, HEX);

  /* scrPad[0]=src[1];
    destn=source>>14;
    Serial.println(destn,HEX);
  */
}

void loop() {
  // put your main code here, to run repeatedly:

}