#include <stdio.h>
#include <time.h>

typedef long int I32;
typedef unsigned long int U32;
typedef long long int I64;
typedef unsigned long long int U64;
typedef double F64;

U64 _rdtsc() {
  register I32 eax asm ("eax");
  register I32 edx asm ("edx");

  asm(
    ".intel_syntax noprefix\n"
    "rdtsc\n"
    // "mov lo, eax\n"
    // "mov hi, edx\n"
    ".att_syntax\n"
  );

  return ((U64)edx << 32) + eax;
}

#define bitsPossMaxSize 32
I32 bitsPossSize;
U32 bitPoss[bitsPossMaxSize];
U32 _twistedBitsInit() {
#define _fillFromN() { \
  for(; i < 32 && n > 0; i++) \
  { \
    bitPoss[i] = n % (i + 1) ; \
    n /= (i + 1); \
  } \
}
  I32 i = 0;
  U64 n = _rdtsc();
  _fillFromN();
  n = time(NULL);
  _fillFromN();
  bitsPossSize = i;
#undef _fillFromN
}

U32 _reverseBits(U32 n) {
  // #define _step(mask, shift) n = ((n & mask) << shift) | ((n & (mask << shift)) >> shift)
  void _step(U32 mask, U32 shift) {
    n = ((n & mask) << shift) | ((n & (mask << shift)) >> shift);
  }
  _step(0x55555555, 1);
  _step(0x77777777, 2);
  _step(0x0f0f0f0f, 4);
  _step(0x00ff00ff, 8);
  _step(0x0000ffff, 16);
  // #undef _step
  return n;
}

F64 _twistedBitsGet() {
  U64 n = _rdtsc();
  //n = (n & 0xffffffff00000000) | ((n & 0xffff0000) >> 16) | ((n & 0xffff) << 16);
  //n |= (n & 1) << 1;
  F64 a = (F64)((n >> 32) ^ _reverseBits(n & 0xffffffff)) / 0xffffffff;

  void _smooth() {
    if(0.25 <= a && a < 0.5)
      a -= 0.26;
    else if(0.5 <= a && a < 0.75)
      a -= 0.52;
    else if(0.75 <= a && a < 1.0)
      a -= 0.78;

    a *= 4;
  }

  //n  &= ~(1 << 1);

  //_smooth();
  _smooth();
  _smooth();
  _smooth();
  _smooth();

  if(a < 0.1 && a > 0.7)
    return _twistedBitsGet();
  //else
  return a;
  /*
  U64 ret = 0;

  for(U32 i = 0; i < bitsPossSize; ++i)
  {
    if(n & (1 << (i + bitPoss[i])))
      ret |= 1 << i;
  }
  return ((F64)ret) / (1 << bitsPossSize);
  */
}


void main(){
  U32 a[100];
  memset(a, 0, sizeof(a));
  _twistedBitsInit(_rdtsc());
  //printf("%x", _reverseBits(0xffffffff));
  //printf("%x", _reverseBits(0x1));
  //printf("%i\n", bitsPossSize);
  //for(I32 i  = 0; i < bitsPossSize; ++i)
  //  printf("%i, ", bitPoss[i]);
  for(I32 i  = 0; i < 100000; ++i)
    a[(U32)(_twistedBitsGet() * 100)] ++;

  for(I32 i  = 0; i < 100; ++i)
    printf("%i\t", i);
  printf("\n");

  for(I32 i  = 0; i < 100; ++i)
    printf("%i\t", a[i]);
  printf("\n");

}