danlark1

#include <cinttypes>

#include <atomic>
#include <memory>
#include <type_traits>

//start 00:20

// genius idea https://en.wikipedia.org/wiki/Tagged_pointer
template <class T>

danlark1

// Installation.
// Abseil, compile with -labseil
// Libdivide as header.
// GMP as header, compile with -lgmp
// Change the private constructor of absl::uin128 to public in order to use public inheritance.
// GMOCK, GUNIT, compile it.
#include "absl/numeric/int128.h"

#include <random>

danlark1

struct GmpDiv {
  uint64_t operator()(uint64_t u1, uint64_t u0, uint64_t v, du_int* r) const {
    mp_limb_t q[2] = {u0, u1};
    mp_limb_t result[2] = {0, 0};
    *r = mpn_divrem_1(result, 0, q, 2, v);
    return result[0];
  }
};

danlark1

// dividend / divisor, remainder is stored in rem.
uint128 __udivmodti4(uint128 dividend, uint128 divisor, uint128* rem) {
  if (divisor > dividend) {
    if (rem)
      *rem = dividend;
    return 0;
  }
  // 64 bit divisor implementation
  ...
  // end

danlark1

#if defined(__x86_64__)
inline uint64_t Divide128Div64To64(uint64_t high, uint64_t low,
                                   uint64_t divisor, uint64_t* remainder) {
  uint64_t result;
  __asm__("divq %[v]"
          : "=a"(result), "=d"(*remainder) // Ouput parametrs, =a for rax, =d for rdx, [v] is an
                                           // alias for divisor, input paramters "a" and "d" for low and high.
          : [v] "r"(divisor), "a"(low), "d"(high));
  return result;
}

danlark1

#if defined(__x86_64__)
inline uint64_t Divide128Div64To64(uint64_t high, uint64_t low,
                                   uint64_t divisor, uint64_t* remainder) {
  uint64_t result;
  __asm__("divq %[v]"
          : "=a"(result), "=d"(*remainder) // Output parametrs, =a for rax, =d for rdx, [v] is an
                                           // alias for divisor, input paramters "a" and "d" for low and high.
          : [v] "r"(divisor), "a"(low), "d"(high));
  return result;
}

danlark1

#include <cinttypes>

uint64_t div(uint64_t u1, uint64_t u0, uint64_t v) {
  uint64_t result;
  uint64_t remainder;
  __asm__("divq %[v]" : "=a"(result), "=d"(remainder) : [v] "r"(v), "a"(u0), "d"(u1));
  return result;
}

int main() {

danlark1

// dividend / divisor, remainder is stored in rem.
uint128 __udivmodti4(uint128 dividend, uint128 divisor, uint128* rem) {
  if (divisor > dividend) {
    if (rem)
      *rem = dividend;
    return 0;
  }
   // Calculate the distance between most significant bits, 128 > shift >= 0.
  int shift = Distance(dividend, divisor);
  divisor <<= shift;

danlark1

#include "int_lib.h"

/*
typedef      int si_int;
typedef unsigned su_int;

typedef          long long di_int;
typedef unsigned long long du_int;

typedef int ti_int __attribute__((mode(TI))); // 128 signed

danlark1

int main() {
    long a = 3;
    long b = 2;
    long c = a + b;
    a = 4;
}