// file: lecture_18/example_00.cc
//
// a simple function that doesn't do much
//

// system include files
//
#include "example.h"

// function: my_function
//
// arguments:
//  long arg1: the first argument
//  long arg2: the second argument
//
// return: a bool indicating status
//
bool my_function(long argv1, long argv2) {

  // how many bytes is a long integer
  //
  fprintf(stdout, "a long integer is %d bytes\n", sizeof(argv1));
  fprintf(stdout, "an int integer is %d bytes\n", sizeof(int));
  fprintf(stdout, "a short integer is %d bytes\n", sizeof(short int));
  fprintf(stdout, "a float is %d bytes\n", sizeof(float));
  fprintf(stdout, "a double is %d bytes\n", sizeof(double));

  // convert the arguments to unsigned char:
  //  note this is dangerous because the range of a long is [-2^31,2^31-1]
  //  the range of a signed char is [-2^7,2^7-1]
  //
  signed char a = (signed char)argv1;
  signed char b = (signed char)argv2;
  fprintf(stdout, "a = %d (%ld)\n", a, argv1);

  // do some bit-level stuff
  //
  fprintf(stdout, "a = %d, b = %d\n", a, b);
  fprintf(stdout, "a & b = %d\n", a & b); 
  fprintf(stdout, "a | b = %d\n", a | b); 
  fprintf(stdout, "a ^ b = %d\n", a ^ b); 
  fprintf(stdout, "~a = %d\n", ~a);   
  fprintf(stdout, "a << 1 = %d\n", a << 1);
  fprintf(stdout, "a >> 1 = %d\n", a >> 1);

  // short integers
  //
  short int s = argv1;
  fprintf(stdout, "s << 1 = %d\n", s << 1);
  fprintf(stdout, "s >> 1 = %d\n", s >> 1);

  // can I bit-shift floats?
  //
  //float f = (float)argv1;
  float f = 27.2727;
  fprintf(stdout, "f << 1 = %d\n", (unsigned int)f << 1);
  fprintf(stdout, "f >> 1 = %d\n", (unsigned int)f >> 1);

  float* jp = &f;
  unsigned int* jpp = (unsigned int*)(void*)jp;
  fprintf(stdout, "jpp << 1 = %d\n", *jpp << 1);
  fprintf(stdout, "jpp >> 1 = %d\n", *jpp >> 1);

  // masking
  //
  unsigned char bbb = (unsigned int)argv1 & MYMASK;
  fprintf(stdout, "argv1 = %u, bbb = %d\n", (unsigned int)argv1, bbb);
  
  // short integers
  //
  /*
  short int ss = argv1 * argv2 & argv1;
  fprintf(stdout, "ss = %ld\n", ss);
  */

  // exit gracefully
  //
  return true;
}