[PATCH] i386 mmx copying bug.

Odd, this is the missing half of the recent fix where we prefetched
too far. Not sure how this bit got dropped. Without it, we still prefetch
past the end of a range of memory.
Also small compiler hint microoptimisations

arch/i386/lib/mmx.c

@@ -31,7 +31,7 @@ void *_mmx_memcpy(void *to, const void *from, size_t len)
 	void *p;
 	int i;
 
-	if (in_interrupt())
+	if (unlikely(in_interrupt()))
 		return __memcpy(to, from, len);
 
 	p = to;
@@ -57,7 +57,7 @@ void *_mmx_memcpy(void *to, const void *from, size_t len)
 		: : "r" (from) );
 		
 	
-	for(; i>0; i--)
+	for(; i>5; i--)
 	{
 		__asm__ __volatile__ (
 		"1:  prefetch 320(%0)\n"
@@ -372,7 +372,7 @@ static void slow_zero_page(void * page)
  
 void mmx_clear_page(void * page)
 {
-	if(in_interrupt())
+	if(unlikely(in_interrupt()))
 		slow_zero_page(page);
 	else
 		fast_clear_page(page);
@@ -392,7 +392,7 @@ static void slow_copy_page(void *to, void *from)
 
 void mmx_copy_page(void *to, void *from)
 {
-	if(in_interrupt())
+	if(unlikely(in_interrupt()))
 		slow_copy_page(to, from);
 	else
 		fast_copy_page(to, from);