--- src/checksum.c.orig	2003-09-20 22:40:44.000000000 +0200
+++ src/checksum.c	2004-11-02 20:36:59.290981656 +0100
@@ -29,6 +29,7 @@
 	movl 16(%esp),%ecx	# Function arg: int len
         movl 12(%esp),%esi	# Function arg: u_char *buff*/
 
+"	push %%ebx						\n"
 "	testl $2, %%esi						\n"		
 "	jz 2f							\n"			
 "	subl $2, %%ecx						\n"		
@@ -84,10 +85,10 @@
 "5:	movb (%%esi),%%cl					\n"
 "6:	addl %%ecx,%%eax					\n"
 "	adcl $0, %%eax						\n"
-"7: 								\n"
+"7: 	pop %%ebx						\n"
        : "=a"(sum)
        : "0"(sum), "c"(len), "S"(buff)
-       : "bx", "dx");
+       : "dx");
 
   return (sum);
 }