diff --git a/p4src/checksum_diff.p4 b/p4src/checksum_diff.p4
index b5f7def..5d5b3c9 100644
--- a/p4src/checksum_diff.p4
+++ b/p4src/checksum_diff.p4
@@ -624,37 +624,37 @@ Echo or Echo Reply Message
         bit<16> localsum = 0;
 
         localsum = localsum + hdr.ipv4.src[15:0];              // 16 bit
-        localsum += hdr.ipv4.src[31:16];             // 16 bit
-        localsum += hdr.ipv4.dst[15:0];              // 16 bit
-        localsum += hdr.ipv4.dst[31:16];             // 16 bit
+        localsum = localsum + hdr.ipv4.src[31:16];             // 16 bit
+        localsum = localsum + hdr.ipv4.dst[15:0];              // 16 bit
+        localsum = localsum + hdr.ipv4.dst[31:16];             // 16 bit
 
-        localsum += hdr.ipv4.totalLen -20;           // 16 bit
-        localsum += (bit<16>) hdr.ipv4.protocol;     // 8 bit
+        localsum = localsum + hdr.ipv4.totalLen -20;           // 16 bit
+        localsum = localsum + (bit<16>) hdr.ipv4.protocol;     // 8 bit
     }
 
     action v6sum() {
         bit<16> localsum = 0;
 
-        localsum += hdr.ipv6.src[15:0];              // 16 bit
-        localsum += hdr.ipv6.src[31:16];             // 16 bit
-        localsum += hdr.ipv6.src[47:32];             // 16 bit
-        localsum += hdr.ipv6.src[63:48];             // 16 bit
-        localsum += hdr.ipv6.src[79:64];             // 16 bit
-        localsum += hdr.ipv6.src[95:80];             // 16 bit
-        localsum += hdr.ipv6.src[111:96];            // 16 bit
-        localsum += hdr.ipv6.src[127:112];           // 16 bit
+        localsum = localsum + hdr.ipv6.src[15:0];              // 16 bit
+        localsum = localsum + hdr.ipv6.src[31:16];             // 16 bit
+        localsum = localsum + hdr.ipv6.src[47:32];             // 16 bit
+        localsum = localsum + hdr.ipv6.src[63:48];             // 16 bit
+        localsum = localsum + hdr.ipv6.src[79:64];             // 16 bit
+        localsum = localsum + hdr.ipv6.src[95:80];             // 16 bit
+        localsum = localsum + hdr.ipv6.src[111:96];            // 16 bit
+        localsum = localsum + hdr.ipv6.src[127:112];           // 16 bit
 
-        localsum += hdr.ipv6.dst[15:0];              // 16 bit
-        localsum += hdr.ipv6.dst[31:16];             // 16 bit
-        localsum += hdr.ipv6.dst[47:32];             // 16 bit
-        localsum += hdr.ipv6.dst[63:48];             // 16 bit
-        localsum += hdr.ipv6.dst[79:64];             // 16 bit
-        localsum += hdr.ipv6.dst[95:80];             // 16 bit
-        localsum += hdr.ipv6.dst[111:96];            // 16 bit
-        localsum += hdr.ipv6.dst[127:112];           // 16 bit
+        localsum = localsum + hdr.ipv6.dst[15:0];              // 16 bit
+        localsum = localsum + hdr.ipv6.dst[31:16];             // 16 bit
+        localsum = localsum + hdr.ipv6.dst[47:32];             // 16 bit
+        localsum = localsum + hdr.ipv6.dst[63:48];             // 16 bit
+        localsum = localsum + hdr.ipv6.dst[79:64];             // 16 bit
+        localsum = localsum + hdr.ipv6.dst[95:80];             // 16 bit
+        localsum = localsum + hdr.ipv6.dst[111:96];            // 16 bit
+        localsum = localsum + hdr.ipv6.dst[127:112];           // 16 bit
 
-        localsum += hdr.ipv6.payload_length;         // 16 bit
-        localsum += (bit<16>) hdr.ipv6.next_header;  // 8 bit
+        localsum = localsum + hdr.ipv6.payload_length;         // 16 bit
+        localsum = localsum + (bit<16>) hdr.ipv6.next_header;  // 8 bit
     }
 
 	/********************** APPLYING TABLES ***********************************/