Here is an example of limiting that same irq (44) to cpus 1024 to 1031:
-[root@moon 44]# echo 1024-1031 > smp_affinity
-[root@moon 44]# cat smp_affinity
+[root@moon 44]# echo 1024-1031 > smp_affinity_list
+[root@moon 44]# cat smp_affinity_list
1024-1031
Note that to do this with a bitmask would require 32 bitmasks of zero