C / C++ / MFC

void ByteSwap2_c(int n, short *a)
{
  
  int i;
  
  for (i=0; i<n; ++i) {
     
    short int tmp=a[i];
    short int pmt;
    ((char*)(&pmt))[1]=((char*)(&tmp))[0];
    ((char*)(&pmt))[0]=((char*)(&tmp))[1]; 
	//printf("%x\n",a[i]);
    a[i]=pmt;
  }
}

#include "stdio.h"

void ByteSwap2_c(int n, short int *a);
void ByteSwap2_asm(int n, short int *a);

void ByteSwap2(int n, short int *a)
{
  int i;
  short *b = (char *) malloc ( n * sizeof(short int));
  for (i=0; i<n; ++i) 
	  b[i]=a[i];

 //ByteSwap2_asm(n,a);
 ByteSwap2_c(n,b);

  for (i=0; i<n; ++i) {
    if (a[i] != b[i]) {
		
      printf("a[%d] (0x%04X) != b[%d] (0x%04X)\n",i,a[i],i,b[i]);
      exit(1);
    }
  }

  free(b);
}

void test2(int n, short int *a, short int *b)
{
  int i;
  ByteSwap2(n,a);
  for (i=0; i<n; ++i) {
    if (a[i] != b[i]) {
      printf("a[%d] (0x%04X) != b[%d] (0x%04X)\n",i,a[i],i,b[i]);
      exit(1);
    }
  }
}

int main()
{
  static short int a[4]={0x0304, 0x8999, 0xef12, 0x5678};
  static short int b[4]={0x0403, 0x9989, 0x12ef, 0x7856};

  test2(4,a,b);

  printf("all tests pass\n");
}