Fixed cache invalidating

kern/mips/cache.S

@@ -3,10 +3,27 @@
 	/* FIXME: This should invalidate only part of memory.  */
 FUNCTION (grub_cpu_flush_cache)
 FUNCTION (grub_arch_sync_caches)
-repeat:
-	cache 1, 0($a0)
-	cache 0, 0($a0)
-	addiu $a0, $a0, 1
-	addiu $a1, $a1, 0xffff
-	bne $a1, $zero, repeat
-	j $31
+	move $t2, $a0
+	addu $t3, $a0, $a1
+	srl $t2, $t2, 5
+	sll $t2, $t2, 5
+	addu $t3, $t3, 0x1f
+	srl $t3, $t3, 5
+	sll $t3, $t3, 5
+	move $t0, $t2
+	subu $t1, $t3, $t2
+r1:
+	cache 1, 0($t0)
+	addiu $t0, $t0, 0x1
+	addiu $t1, $t1, 0xffff
+	bne $t1, $zero, r1
+	sync
+	move $t0, $t2
+	subu $t1, $t3, $t2
+r2:
+	cache 0, 0($t0)
+	addiu $t0, $t0, 0x1
+	addiu $t1, $t1, 0xffff
+	bne $t1, $zero, r2
+	sync
+	j $ra