diff --git a/library/timing.c b/library/timing.c
index 8322411..c8fa653 100644
--- a/library/timing.c
+++ b/library/timing.c
@@ -25,6 +25,13 @@
 
 #include "polarssl/config.h"
 
+#if defined(POLARSSL_SELF_TEST) && defined(POLARSSL_PLATFORM_C)
+#include "polarssl/platform.h"
+#else
+#include <stdio.h>
+#define polarssl_printf     printf
+#endif
+
 #if defined(POLARSSL_TIMING_C) && !defined(POLARSSL_TIMING_ALT)
 
 #include "polarssl/timing.h"
@@ -254,7 +261,7 @@
     Sleep( milliseconds );
 }
 
-#else
+#else /* _WIN32 && !EFIX64 && !EFI32 */
 
 unsigned long get_timer( struct hr_time *val, int reset )
 {
@@ -282,7 +289,7 @@
     usleep( milliseconds * 1000 );
 }
 
-#else
+#else /* INTEGRITY */
 
 static void sighandler( int signum )
 {
@@ -308,6 +315,120 @@
 }
 #endif /* INTEGRITY */
 
-#endif
+#endif /* _WIN32 && !EFIX64 && !EFI32 */
 
-#endif
+#if defined(POLARSSL_SELF_TEST)
+
+/*
+ * Checkup routine
+ */
+int timing_self_test( int verbose )
+{
+    unsigned long cycles, ratio;
+    unsigned long millisecs, secs;
+    int hardfail;
+    struct hr_time hires;
+
+    if( verbose != 0)
+        polarssl_printf( "  TIMING tests warning: will take some time!\n" );
+
+    if( verbose != 0 )
+        polarssl_printf( "  TIMING test #1 (m_sleep   / get_timer): " );
+
+    for( secs = 1; secs <= 3; secs++ )
+    {
+        (void) get_timer( &hires, 1 );
+
+        m_sleep( 1000 * secs );
+
+        millisecs = get_timer( &hires, 0 );
+
+        if( millisecs < 900 * secs || millisecs > 1100 * secs )
+        {
+            if( verbose != 0 )
+                polarssl_printf( "failed\n" );
+
+            return( 1 );
+        }
+    }
+
+    if( verbose != 0 )
+        polarssl_printf( "passed\n" );
+
+    if( verbose != 0 )
+        polarssl_printf( "  TIMING test #2 (set_alarm / get_timer): " );
+
+    for( secs = 1; secs <= 3; secs++ )
+    {
+        (void) get_timer( &hires, 1 );
+
+        set_alarm( secs );
+        while( !alarmed )
+            ;
+
+        millisecs = get_timer( &hires, 0 );
+
+        if( millisecs < 900 * secs || millisecs > 1100 * secs )
+        {
+            if( verbose != 0 )
+                polarssl_printf( "failed\n" );
+
+            return( 1 );
+        }
+    }
+
+    if( verbose != 0 )
+        polarssl_printf( "passed\n" );
+
+    if( verbose != 0 )
+        polarssl_printf( "  TIMING test #3 (hardclock / m_sleep  ): " );
+
+    /*
+     * Allow one failure for possible counter wrapping.
+     * On a 4Ghz 32-bit machine the cycle counter wraps about once per second;
+     * since the whole test is about 10ms, it shouldn't happen twice in a row.
+     */
+    hardfail = 0;
+
+hard_test:
+    if( hardfail > 1 )
+    {
+        if( verbose != 0 )
+            polarssl_printf( "failed\n" );
+
+        return( 1 );
+    }
+
+    /* Get a reference ratio cycles/ms */
+    cycles = hardclock();
+    m_sleep( 1 );
+    cycles = hardclock() - cycles;
+    ratio = cycles / 1;
+
+    for( millisecs = 2; millisecs <= 4; millisecs++ )
+    {
+        cycles = hardclock();
+        m_sleep( millisecs );
+        cycles = hardclock() - cycles;
+
+        /* Allow variation up to 20% */
+        if( cycles / millisecs < ratio - ratio / 5 ||
+            cycles / millisecs > ratio + ratio / 5 )
+        {
+            hardfail++;
+            goto hard_test;
+        }
+    }
+
+    if( verbose != 0 )
+        polarssl_printf( "passed\n" );
+
+    if( verbose != 0 )
+        polarssl_printf( "\n" );
+
+    return( 0 );
+}
+
+#endif /* POLARSSL_SELF_TEST */
+
+#endif /* POLARSSL_TIMING_C && !POLARSSL_TIMING_ALT */