diff -uNp ish201a5.orig/crc32.c ish201a5/crc32.c
--- ish201a5.orig/crc32.c	Wed Apr 20 14:23:00 1994
+++ ish201a5/crc32.c	Tue Dec 20 18:56:44 2011
@@ -78,6 +78,7 @@ unsigned char *arg;
 int len;
 unsigned long crc;
 {
+    crc &= 0xffffffffU;
     while(--len >= 0) {
 	crc = crc >> 8 ^ crctbl[(crc & 0xff) ^ *arg++];
     }
diff -uNp ish201a5.orig/mvol.c ish201a5/mvol.c
--- ish201a5.orig/mvol.c	Sun Jan  7 19:47:17 1996
+++ ish201a5/mvol.c	Tue Dec 20 20:07:46 2011
@@ -248,7 +248,7 @@ unsigned char    *p;
     }
     close(id);
     close(od);
-    crc32 = ~crc32;
+    crc32 = ~crc32 & 0xffffffffU;
     crc16 = ~crc16;
     if (crc32 == ncrc32 && crc16 == ncrc16) {
 	/* checksum OK */