/* Midterm practice #4.  Implement the following function according to
 * the specification.  Follow the C-assembly interface conventions of
 * the lab's compiler and assembler.
 *
 * In:  msg - null-terminated string
 * Out: <none>
 * Converts the lowercase letters of msg into uppercase letters.
 * Characters other than lowercase letters are not modified.
 * Note: 'A' is $41 in ASCII, while 'a' is $61.
 */
void yell(char * msg);