--- dip-3.3.7o/command.c.orig	Thu Jan 21 15:37:13 1999
+++ dip-3.3.7o/command.c	Thu Jan 21 15:45:04 1999
@@ -2585,6 +2585,92 @@
   return((~sum) & 0xffff);
 }
 
+#elif defined (__arm__)
+
+/*
+ *	This is a version of ip_compute_csum() optimized for IP headers,
+ *	which always checksum on 4 octet boundaries.
+ *
+ *	Converted and optimised for ARM by R. M. King.
+ *
+ *	Note: the order that the LDM registers are loaded with respect to
+ *	the adc's doesn't matter.
+ */
+static inline unsigned short
+ip_fast_csum(unsigned char * iph, unsigned int ihl)
+{
+	unsigned int sum, tmp1;
+
+    __asm__ __volatile__("
+	sub	%2, %2, #5
+	ldr	%0, [%1], #4
+	ldr	%3, [%1], #4
+	adds	%0, %0, %3
+	ldr	%3, [%1], #4
+	adcs	%0, %0, %3
+	ldr	%3, [%1], #4
+	adcs	%0, %0, %3
+1:	ldr	%3, [%1], #4
+	adcs	%0, %0, %3
+	tst	%2, #15
+	subne	%2, %2, #1
+	bne	1b
+	adc	%0, %0, #0
+	adds	%0, %0, %0, lsl #16
+	addcs	%0, %0, #0x10000
+	mvn	%0, %0
+	mov	%0, %0, lsr #16
+	"
+	: "=&r" (sum), "=&r" (iph), "=&r" (ihl), "=&r" (tmp1)
+	: "1" (iph), "2" (ihl));
+	return(sum);
+}
+
+/*
+ * 	Fold a partial checksum without adding pseudo headers
+ */
+static inline unsigned int
+csum_fold(unsigned int sum)
+{
+	__asm__("
+	adds	%0, %0, %0, lsl #16
+	addcs	%0, %0, #0x10000"
+	: "=r" (sum)
+	: "0" (sum));
+	return (~sum) >> 16;
+}
+
+static inline unsigned long
+csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
+		   unsigned short proto, unsigned int sum)
+{
+	__asm__("
+	adds	%0, %0, %1
+	adcs	%0, %0, %2
+	adcs	%0, %0, %3
+	adc	%0, %0, #0"
+	: "=&r"(sum)
+	: "r" (daddr), "r" (saddr), "r" ((ntohs(len)<<16)+proto*256), "0" (sum));
+	return sum;
+}	
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+static inline unsigned short int
+csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len,
+		  unsigned short proto, unsigned int sum)
+{
+	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
+}
+
+static unsigned short
+udp_check(struct udphdr *uh, int len,
+	unsigned long saddr, unsigned long daddr)
+{
+	return(csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, 0));
+}
+
 #else
 
 #error You need to write tcp/ip checksum routines for your architecture