diff --git a/src/os/hpux/hpux_sigar.c b/src/os/hpux/hpux_sigar.c
index f33e300e..e6cd308c 100644
--- a/src/os/hpux/hpux_sigar.c
+++ b/src/os/hpux/hpux_sigar.c
@@ -549,12 +549,6 @@ int sigar_file_system_list_get(sigar_t *sigar,
     return SIGAR_OK;
 }
 
-/* XXX this is exactly the same as linux and solaris is darn close */
-#include <sys/vfs.h>
-
-#define SIGAR_FS_BLOCKS_TO_BYTES(buf, f) \
-    (((sigar_uint64_t)buf.f * (buf.f_bsize / 512)) >> 1)
-
 static int create_fsdev_cache(sigar_t *sigar)
 {
     sigar_file_system_list_t fslist;
@@ -593,20 +587,30 @@ int sigar_disk_usage_get(sigar_t *sigar, const char *name,
     return SIGAR_ENOTIMPL;
 }
 
+/* XXX this is exactly the same as linux and solaris is darn close */
+#include <sys/vfs.h>
+
+#define SIGAR_FS_BLOCKS_TO_BYTES(val, bsize) ((val * bsize) >> 1)
+
 int sigar_file_system_usage_get(sigar_t *sigar,
                                 const char *dirname,
                                 sigar_file_system_usage_t *fsusage)
 {
     struct statfs buf;
     struct stat sb;
-
+    sigar_uint64_t val, bsize;
+    
     if (statfs(dirname, &buf) != 0) {
         return errno;
     }
 
-    fsusage->total = SIGAR_FS_BLOCKS_TO_BYTES(buf, f_blocks);
-    fsusage->free  = SIGAR_FS_BLOCKS_TO_BYTES(buf, f_bfree);
-    fsusage->avail = SIGAR_FS_BLOCKS_TO_BYTES(buf, f_bavail);
+    bsize = buf.f_bsize / 512;
+    val = buf.f_blocks;
+    fsusage->total = SIGAR_FS_BLOCKS_TO_BYTES(val, bsize);
+    val = buf.f_bfree;
+    fsusage->free  = SIGAR_FS_BLOCKS_TO_BYTES(val, bsize);
+    val = buf.f_bavail;
+    fsusage->avail = SIGAR_FS_BLOCKS_TO_BYTES(val, bsize);
     fsusage->used  = fsusage->total - fsusage->free;
     fsusage->files = buf.f_files;
     fsusage->free_files = buf.f_ffree;