cuda-samples/Samples/simpleAtomicIntrinsics/simpleAtomicIntrinsics_cpu.cpp

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#include <math.h>
#include <stdio.h>

#define min(a, b) (a) < (b) ? (a) : (b)
#define max(a, b) (a) > (b) ? (a) : (b)

////////////////////////////////////////////////////////////////////////////////
// export C interface
extern "C" int computeGold(int *gpuData, const int len);

////////////////////////////////////////////////////////////////////////////////
//! Compute reference data set
//! Each element is multiplied with the number of threads / array length
//! @param reference  reference data, computed but preallocated
//! @param idata      input data as provided to device
//! @param len        number of elements in reference / idata
////////////////////////////////////////////////////////////////////////////////
int computeGold(int *gpuData, const int len) {
  int val = 0;

  for (int i = 0; i < len; ++i) {
    val += 10;
  }

  if (val != gpuData[0]) {
    printf("atomicAdd failed\n");
    return false;
  }

  val = 0;

  for (int i = 0; i < len; ++i) {
    val -= 10;
  }

  if (val != gpuData[1]) {
    printf("atomicSub failed\n");
    return false;
  }

  bool found = false;

  for (int i = 0; i < len; ++i) {
    // third element should be a member of [0, len)
    if (i == gpuData[2]) {
      found = true;
      break;
    }
  }

  if (!found) {
    printf("atomicExch failed\n");
    return false;
  }

  val = -(1 << 8);

  for (int i = 0; i < len; ++i) {
    // fourth element should be len-1
    val = max(val, i);
  }

  if (val != gpuData[3]) {
    printf("atomicMax failed\n");
    return false;
  }

  val = 1 << 8;

  for (int i = 0; i < len; ++i) {
    val = min(val, i);
  }

  if (val != gpuData[4]) {
    printf("atomicMin failed\n");
    return false;
  }

  int limit = 17;
  val = 0;

  for (int i = 0; i < len; ++i) {
    val = (val >= limit) ? 0 : val + 1;
  }

  if (val != gpuData[5]) {
    printf("atomicInc failed\n");
    return false;
  }

  limit = 137;
  val = 0;

  for (int i = 0; i < len; ++i) {
    val = ((val == 0) || (val > limit)) ? limit : val - 1;
  }

  if (val != gpuData[6]) {
    printf("atomicDec failed\n");
    return false;
  }

  found = false;

  for (int i = 0; i < len; ++i) {
    // eighth element should be a member of [0, len)
    if (i == gpuData[7]) {
      found = true;
      break;
    }
  }

  if (!found) {
    printf("atomicCAS failed\n");
    return false;
  }

  val = 0xff;

  for (int i = 0; i < len; ++i) {
    // 9th element should be 1
    val &= (2 * i + 7);
  }

  if (val != gpuData[8]) {
    printf("atomicAnd failed\n");
    return false;
  }

  val = 0;

  for (int i = 0; i < len; ++i) {
    // 10th element should be 0xff
    val |= (1 << i);
  }

  if (val != gpuData[9]) {
    printf("atomicOr failed\n");
    return false;
  }

  val = 0xff;

  for (int i = 0; i < len; ++i) {
    // 11th element should be 0xff
    val ^= i;
  }

  if (val != gpuData[10]) {
    printf("atomicXor failed\n");
    return false;
  }

  return true;
}