提交: f1f90523b1c49f05a4a8215ba1de23dda9bcd43b - evil_int (git)

Some kinds of integer abuse (bugs and vulnerabilities) that can be found in programs.

Commit MetaInfo

• 修订版: f1f90523b1c49f05a4a8215ba1de23dda9bcd43b (tree)
• 时间: 2020-11-13 20:24:59
• 作者: Joel Matthew Rees <joel.rees@gmai...>
• Commiter: Joel Matthew Rees

Log Message

intermediate state adding byte order simulation functions

更改概述

• modified: evil_int.c

差异

--- a/evil_int.c
+++ b/evil_int.c
@@ -1,234 +1,298 @@
-/* A little program to demonstrate a few of the dangers 
-** of aliasing pointers to different types of integers.
-**
-** To fully appreciate the effects,
-** compile and run this code on both LSB1st and MSB1st CPUs.
-**
-** Written in response to a thread on the TRS-80 Color Computer FB group.
-** 
-** Joel Rees, Amagasaki, Japan, November 2020.
-*/
-
-
-#include <stdlib.h>
-#include <limits.h>
-#include <stdio.h>
-
-
-typedef char * byteptr_t;
-typedef short * shortptr_t;
-typedef long * longptr_t;
-
-
-int main( int argc, char *argv[] )
-{
-  short int shorttest[ 3 ] = { 0, 0, 0 };
-  long int longtest[ 3 ] = { 0, 0, 0 };
-  shortptr_t shortptr;
-  longptr_t longptr;
-
-  printf( "Note that both\n"
-    "least significant first and most significant first\n"
-    "give unfortanate results.\n"
-    "Different, but both unfortunate.\n"
-    "Now that you know they do, see if you can figure out why.\n\n" );
-
-  printf( "Let's start with referring to a long as a short, all target bits clear.\n\n" );
-
-  shortptr = (short *) &longtest[ 1 ];
-
-  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "Test: ( * shortptr ) = 1 \n" );
-
-  ( * shortptr ) = 1;
-
-  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "We thought we wrote: %d. We actually wrote %ld between %ld and %ld.\n",
-    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ]  );
-  printf( "In hexadecimal,\n" );
-  printf( "We thought we wrote: %x. We actually wrote %lx between %lx and %lx.\n",
-    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ] );
-
-  printf( "\nAgain, setting all target bits,\n" );
-
-  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = -1;
-
-  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "Test: ( * shortptr ) = 1 \n" );
-
-  ( * shortptr ) = 1;
-
-  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "We thought we wrote: %d. We actually wrote %ld between %ld and %ld.\n",
-    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ]  );
-  printf( "In hexadecimal,\n" );
-  printf( "We thought we wrote: %x. We actually wrote %lx between %lx and %lx.\n",
-    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ] );
-
-  printf( "\n\nClearing all target bits,\n" );
-
-  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = 0;
-
-  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "Test: ( * shortptr ) = -1 \n" );
-
-  ( * shortptr ) = -1;
-
-  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "We thought we wrote: %d. We actually wrote %ld between %ld and %ld.\n",
-    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ]  );
-  printf( "In hexadecimal,\n" );
-  printf( "We thought we wrote: %x. We actually wrote %lx between %lx and %lx.\n",
-    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ] );
-
-  printf( "\nAgain, setting all target bits,\n" );
-
-  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = -1;
-
-  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "Test: ( * shortptr ) = -1 \n" );
-
-  ( * shortptr ) = -1;
-
-  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "We thought we wrote: %d. We actually wrote %ld between %ld and %ld.\n",
-    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ]  );
-  printf( "In hexadecimal,\n" );
-  printf( "We thought we wrote: %x. We actually wrote %lx between %lx and %lx.\n",
-    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ] );
-
-  printf( "\n\nTime for arithmetic on small integers.\n" );
-  printf( "Clearing ..." );
-  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = 0;
-  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "Test: ( * shortptr ) -= 1 (subtract 1)\n" );
-  ( * shortptr ) -= 1;
-  printf( "* shortptr sees %d (%x)\n", * shortptr, *shortptr );
-  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-
-  printf( "\nClearing ..." );
-  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = 0;
-  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-  printf( "Test: ( * shortptr ) += 1 (add 1)\n" );
-  ( * shortptr ) += 1;
-  printf( "* shortptr sees %d (%x)\n", * shortptr, *shortptr );
-  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
-    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
-
-
-/********/
-
-  printf( "\n\n\nNow let's refer to a short as a long.\n\n" );
-
-  longptr = (long *) &shorttest[ 1 ];
-
-  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
-  printf( "Test: ( * longptr ) = 1 \n" );
-
-  ( * longptr ) = 1;
-
-  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
-  printf( "We thought we wrote: %ld. We actually wrote %d between %d and %d.\n",
-    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
-  printf( "In hexadecimal,\n" );
-  printf( "We thought we wrote: %lx. We actually wrote %x between %x and %x.\n",
-    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
-
-  printf( "\nAgain, setting all target bits,\n" );
-
-  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = -1;
-
-  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
-  printf( "Test: ( * longptr ) = 1 \n" );
-
-  ( * longptr ) = 1;
-
-  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
-  printf( "We thought we wrote: %ld. We actually wrote %d between %d and %d.\n",
-    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
-  printf( "In hexadecimal,\n" );
-  printf( "We thought we wrote: %lx. We actually wrote %x between %x and %x.\n",
-    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
-
-
-  printf( "\n\nClearing all target bits,\n" );
-
-  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = 0;
-
-  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
-  printf( "Test: ( * longptr ) = -1 \n" );
-
-  ( * longptr ) = -1;
-
-  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
-  printf( "We thought we wrote: %ld. We actually wrote %d between %d and %d.\n",
-    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
-  printf( "In hexadecimal,\n" );
-  printf( "We thought we wrote: %lx. We actually wrote %x between %x and %x.\n",
-    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
-
-  printf( "\nAgain, setting all target bits,\n" );
-
-  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = -1;
-
-  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
-  printf( "Test: ( * longptr ) = -1 \n" );
-
-  ( * longptr ) = -1;
-
-  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
-  printf( "We thought we wrote: %ld. We actually wrote %d between %d and %d.\n",
-    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
-  printf( "In hexadecimal,\n" );
-  printf( "We thought we wrote: %lx. We actually wrote %x between %x and %x.\n",
-    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
-
-  printf( "\n\nTime for arithmetic on small integers.\n" );
-  printf( "Clearing ..." );
-  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = 0;
-  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ] );
-  printf( "Test: ( * longptr ) -= 1 (subtract 1)\n" );
-  ( * longptr ) -= 1;
-  printf( "* longptr sees %d (%x)\n", * shortptr, *shortptr );
-  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ] );
-
-  printf( "\nClearing ..." );
-  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = 0;
-  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ] );
-  printf( "Test: ( * longptr ) += 1 (add 1)\n" );
-  ( * longptr ) += 1;
-  printf( "* longptr sees %d (%x)\n", * shortptr, *shortptr );
-  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
-    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ] );
-
-  printf( "To get the full effect of this,\n"
-    "be sure to compile and run on both least significant first\n"
-    "and most significant first architectures.\n"
-    "Ask yourself, \n"
-    "on which architecture will you notice the effects more quickly?\n\n" );
-
-
-  return EXIT_SUCCESS;
-}
+/* A little program to demonstrate a few of the dangers 
+** of aliasing pointers to different types of integers.
+**
+** To fully appreciate the effects,
+** compile and run this code on both LSB1st and MSB1st CPUs.
+**
+** Written in response to a thread on the TRS-80 Color Computer FB group.
+** 
+** Joel Rees, Amagasaki, Japan, November 2020.
+*/
+
+
+#include <stdlib.h>
+#include <limits.h>
+#include <stdio.h>
+
+
+typedef unsigned char byte_t;
+typedef byte_t * byteptr_t;
+typedef short * shortptr_t;
+typedef long * longptr_t;
+
+
+#define writeMSB1st( type, val, ptr )	\
+void write##type##MSB1st( type val; type##ptr_t ptr )	\
+{	\
+  byteptr_t bytes = ( (byteptr_t) ptr ) + sizeof val;	\
+  for ( ;; ) 	\
+  {	\
+    * --bytes = (byte_t) ( val & UCHAR_MAX );	\
+    if ( bytes <= (byteptr_t) ptr ) break;	\
+    val >>= CHAR_BIT;	\
+  }	\
+}
+
+
+#define writeLSB1st( type )	\
+void write##type##LSB1st( type value; type##ptr_t memptr )	\
+{	\
+  byteptr_t bytes = ( (byteptr_t) memptr );	\
+  byteptr_t bound = bytes + sizeof value;	\
+  for ( ;; )	\
+  {	\
+    * bytes++ = (byte_t) ( value & UCHAR_MAX );	\
+    if ( bytes >= bound ) break;	\
+    value >>= CHAR_BIT;	\
+  }	\
+}
+
+
+long readlongMSB1st( longptr_t memptr )
+{
+  long value = 0;
+  byteptr_t bytes = ( (byteptr_t) memptr ) + sizeof value;
+  while ( bytes >= (byteptr_t) memptr )
+  {
+    value |= * --bytes;
+    value <<= CHAR_BIT;
+  }
+}
+
+
+long readlongLSB1st( longptr_t memptr )
+{
+  long value = 0;
+  byteptr_t bytes = (byteptr_t) memptr;
+  byteptr_t bound = bytes + sizeof value;
+  while ( bytes < bound )
+  {
+    value |= * bytes++;
+    value <<= CHAR_BIT;
+  }
+}
+
+
+writeMSB1st( long, value, memptr )
+
+writeMSB1st( short )
+
+writeLSB1st( long )
+
+writeLSB1st( short )
+
+
+
+int main( int argc, char *argv[] )
+{
+  short int shorttest[ 3 ] = { 0, 0, 0 };
+  long int longtest[ 3 ] = { 0, 0, 0 };
+  shortptr_t shortptr;
+  longptr_t longptr;
+
+  printf( "Note that both\n"
+    "least significant first and most significant first\n"
+    "give unfortanate results.\n"
+    "Different, but both unfortunate.\n"
+    "Now that you know they do, see if you can figure out why.\n\n" );
+
+  printf( "Let's start with referring to a long as a short, all target bits clear.\n\n" );
+
+  shortptr = (short *) &longtest[ 1 ];
+
+  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "Test: ( * shortptr ) = 1 \n" );
+
+  ( * shortptr ) = 1;
+
+  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "We thought we wrote: %d. We actually wrote %ld between %ld and %ld.\n",
+    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ]  );
+  printf( "In hexadecimal,\n" );
+  printf( "We thought we wrote: %x. We actually wrote %lx between %lx and %lx.\n",
+    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ] );
+
+  printf( "\nAgain, setting all target bits,\n" );
+
+  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = -1;
+
+  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "Test: ( * shortptr ) = 1 \n" );
+
+  ( * shortptr ) = 1;
+
+  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "We thought we wrote: %d. We actually wrote %ld between %ld and %ld.\n",
+    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ]  );
+  printf( "In hexadecimal,\n" );
+  printf( "We thought we wrote: %x. We actually wrote %lx between %lx and %lx.\n",
+    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ] );
+
+  printf( "\n\nClearing all target bits,\n" );
+
+  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = 0;
+
+  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "Test: ( * shortptr ) = -1 \n" );
+
+  ( * shortptr ) = -1;
+
+  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "We thought we wrote: %d. We actually wrote %ld between %ld and %ld.\n",
+    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ]  );
+  printf( "In hexadecimal,\n" );
+  printf( "We thought we wrote: %x. We actually wrote %lx between %lx and %lx.\n",
+    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ] );
+
+  printf( "\nAgain, setting all target bits,\n" );
+
+  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = -1;
+
+  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "Test: ( * shortptr ) = -1 \n" );
+
+  ( * shortptr ) = -1;
+
+  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "We thought we wrote: %d. We actually wrote %ld between %ld and %ld.\n",
+    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ]  );
+  printf( "In hexadecimal,\n" );
+  printf( "We thought we wrote: %x. We actually wrote %lx between %lx and %lx.\n",
+    * shortptr, longtest[ 1 ], longtest[ 0 ], longtest[ 2 ] );
+
+  printf( "\n\nTime for arithmetic on small integers.\n" );
+  printf( "Clearing ..." );
+  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = 0;
+  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "Test: ( * shortptr ) -= 1 (subtract 1)\n" );
+  ( * shortptr ) -= 1;
+  printf( "* shortptr sees %d (%x)\n", * shortptr, *shortptr );
+  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+
+  printf( "\nClearing ..." );
+  longtest[ 0 ] = longtest[ 1 ] = longtest[ 2 ] = 0;
+  printf( "longtest before: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+  printf( "Test: ( * shortptr ) += 1 (add 1)\n" );
+  ( * shortptr ) += 1;
+  printf( "* shortptr sees %d (%x)\n", * shortptr, *shortptr );
+  printf( "longtest after: %ld %ld %ld (hex: %lx %lx %lx)\n",
+    longtest[ 0 ], longtest[ 1 ], longtest[ 2 ], longtest[ 0 ], longtest[ 1 ], longtest[ 2 ] );
+
+
+/********/
+
+  printf( "\n\n\nNow let's refer to a short as a long.\n\n" );
+
+  longptr = (long *) &shorttest[ 1 ];
+
+  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
+  printf( "Test: ( * longptr ) = 1 \n" );
+
+  ( * longptr ) = 1;
+
+  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
+  printf( "We thought we wrote: %ld. We actually wrote %d between %d and %d.\n",
+    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
+  printf( "In hexadecimal,\n" );
+  printf( "We thought we wrote: %lx. We actually wrote %x between %x and %x.\n",
+    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
+
+  printf( "\nAgain, setting all target bits,\n" );
+
+  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = -1;
+
+  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
+  printf( "Test: ( * longptr ) = 1 \n" );
+
+  ( * longptr ) = 1;
+
+  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
+  printf( "We thought we wrote: %ld. We actually wrote %d between %d and %d.\n",
+    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
+  printf( "In hexadecimal,\n" );
+  printf( "We thought we wrote: %lx. We actually wrote %x between %x and %x.\n",
+    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
+
+
+  printf( "\n\nClearing all target bits,\n" );
+
+  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = 0;
+
+  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
+  printf( "Test: ( * longptr ) = -1 \n" );
+
+  ( * longptr ) = -1;
+
+  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
+  printf( "We thought we wrote: %ld. We actually wrote %d between %d and %d.\n",
+    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
+  printf( "In hexadecimal,\n" );
+  printf( "We thought we wrote: %lx. We actually wrote %x between %x and %x.\n",
+    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
+
+  printf( "\nAgain, setting all target bits,\n" );
+
+  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = -1;
+
+  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
+  printf( "Test: ( * longptr ) = -1 \n" );
+
+  ( * longptr ) = -1;
+
+  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ]  );
+  printf( "We thought we wrote: %ld. We actually wrote %d between %d and %d.\n",
+    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
+  printf( "In hexadecimal,\n" );
+  printf( "We thought we wrote: %lx. We actually wrote %x between %x and %x.\n",
+    * longptr, shorttest[ 1 ], shorttest[ 0 ], shorttest[ 2 ] );
+
+  printf( "\n\nTime for arithmetic on small integers.\n" );
+  printf( "Clearing ..." );
+  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = 0;
+  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ] );
+  printf( "Test: ( * longptr ) -= 1 (subtract 1)\n" );
+  ( * longptr ) -= 1;
+  printf( "* longptr sees %d (%x)\n", * shortptr, *shortptr );
+  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ] );
+
+  printf( "\nClearing ..." );
+  shorttest[ 0 ] = shorttest[ 1 ] = shorttest[ 2 ] = 0;
+  printf( "shorttest before: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ] );
+  printf( "Test: ( * longptr ) += 1 (add 1)\n" );
+  ( * longptr ) += 1;
+  printf( "* longptr sees %d (%x)\n", * shortptr, *shortptr );
+  printf( "shorttest after: %d %d %d (hex: %x %x %x)\n",
+    shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ], shorttest[ 0 ], shorttest[ 1 ], shorttest[ 2 ] );
+
+  printf( "To get the full effect of this,\n"
+    "be sure to compile and run on both least significant first\n"
+    "and most significant first architectures.\n"
+    "Ask yourself, \n"
+    "on which architecture will you notice the effects more quickly?\n\n" );
+
+
+  return EXIT_SUCCESS;
+}
+