TestIntrinsics.c

#include <winpr/crt.h>
#include <winpr/sysinfo.h>
#include <winpr/windows.h>
 
#include <winpr/intrin.h>
 
static BOOL g_LZCNT = FALSE;
 
static INLINE UINT32 lzcnt_s(UINT32 x)
{
  if (!x)
    return 32;
 
  if (!g_LZCNT)
  {
    UINT32 y = 0;
    int n = 32;
    y = x >> 16;
    if (y != 0)
    {
      n = n - 16;
      x = y;
    }
    y = x >> 8;
    if (y != 0)
    {
      n = n - 8;
      x = y;
    }
    y = x >> 4;
    if (y != 0)
    {
      n = n - 4;
      x = y;
    }
    y = x >> 2;
    if (y != 0)
    {
      n = n - 2;
      x = y;
    }
    y = x >> 1;
    if (y != 0)
      return n - 2;
    return n - x;
  }
 
  return __lzcnt(x);
}
 
static int test_lzcnt(void)
{
  if (lzcnt_s(0x1) != 31)
  {
    (void)fprintf(stderr, "__lzcnt(0x1) != 31: %" PRIu32 "\n", __lzcnt(0x1));
    return -1;
  }
 
  if (lzcnt_s(0xFF) != 24)
  {
    (void)fprintf(stderr, "__lzcnt(0xFF) != 24\n");
    return -1;
  }
 
  if (lzcnt_s(0xFFFF) != 16)
  {
    (void)fprintf(stderr, "__lzcnt(0xFFFF) != 16\n");
    return -1;
  }
 
  if (lzcnt_s(0xFFFFFF) != 8)
  {
    (void)fprintf(stderr, "__lzcnt(0xFFFFFF) != 8\n");
    return -1;
  }
 
  if (lzcnt_s(0xFFFFFFFF) != 0)
  {
    (void)fprintf(stderr, "__lzcnt(0xFFFFFFFF) != 0\n");
    return -1;
  }
 
  return 0;
}
 
static int test_lzcnt16(void)
{
  if (__lzcnt16(0x1) != 15)
  {
    (void)fprintf(stderr, "__lzcnt16(0x1) != 15\n");
    return -1;
  }
 
  if (__lzcnt16(0xFF) != 8)
  {
    (void)fprintf(stderr, "__lzcnt16(0xFF) != 8\n");
    return -1;
  }
 
  if (__lzcnt16(0xFFFF) != 0)
  {
    (void)fprintf(stderr, "__lzcnt16(0xFFFF) != 0\n");
    return -1;
  }
 
  return 0;
}
 
int TestIntrinsics(int argc, char* argv[])
{
 
  WINPR_UNUSED(argc);
  WINPR_UNUSED(argv);
 
  g_LZCNT = IsProcessorFeaturePresentEx(PF_EX_LZCNT);
 
  printf("LZCNT available: %" PRId32 "\n", g_LZCNT);
 
  // test_lzcnt16();
  return test_lzcnt();
}