i386/linux/linux-2.3.21/include/asm-m68k/checksum.h

   1 #ifndef _M68K_CHECKSUM_H
   2 #define _M68K_CHECKSUM_H
   3
   4 /*
   5  * computes the checksum of a memory block at buff, length len,
   6  * and adds in "sum" (32-bit)
   7  *
   8  * returns a 32-bit number suitable for feeding into itself
   9  * or csum_tcpudp_magic
  10  *
  11  * this function must be called with even lengths, except
  12  * for the last fragment, which may be odd
  13  *
  14  * it's best to have buff aligned on a 32-bit boundary
  15  */
  16 unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
  17
  18 /*
  19  * the same as csum_partial, but copies from src while it
  20  * checksums
  21  *
  22  * here even more important to align src and dst on a 32-bit (or even
  23  * better 64-bit) boundary
  24  */
  25
  26 unsigned int csum_partial_copy(const char *src, char *dst, int len, int sum);
  27
  28
  29 /*
  30  * the same as csum_partial_copy, but copies from user space.
  31  *
  32  * here even more important to align src and dst on a 32-bit (or even
  33  * better 64-bit) boundary
  34  */
  35
  36 extern unsigned int csum_partial_copy_from_user(const char *src, char *dst,
  37                                                 int len, int sum, int *csum_err);
  38
  39 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  40         csum_partial_copy((src), (dst), (len), (sum))
  41
  42 /*
  43  *      This is a version of ip_compute_csum() optimized for IP headers,
  44  *      which always checksum on 4 octet boundaries.
  45  *
  46  */
  47 static inline unsigned short
  48 ip_fast_csum(unsigned char *iph, unsigned int ihl)
  49 {
  50         unsigned int sum = 0;
  51
  52         __asm__ ("subqw #1,%2\n"
  53                  "1:\t"
  54                  "movel %1@+,%/d0\n\t"
  55                  "addxl %/d0,%0\n\t"
  56                  "dbra  %2,1b\n\t"
  57                  "movel %0,%/d0\n\t"
  58                  "swap  %/d0\n\t"
  59                  "addxw %/d0,%0\n\t"
  60                  "clrw  %/d0\n\t"
  61                  "addxw %/d0,%0\n\t"
  62                  : "=d" (sum), "=a" (iph), "=d" (ihl)
  63                  : "0" (sum), "1" (iph), "2" (ihl)
  64                  : "d0");
  65         return ~sum;
  66 }
  67
  68 /*
  69  *      Fold a partial checksum
  70  */
  71
  72 static inline unsigned int csum_fold(unsigned int sum)
  73 {
  74         unsigned int tmp = sum;
  75         __asm__("swap %1\n\t"
  76                 "addw %1, %0\n\t"
  77                 "clrw %1\n\t"
  78                 "addxw %1, %0"
  79                 : "=&d" (sum), "=&d" (tmp)
  80                 : "0" (sum), "1" (sum));
  81         return ~sum;
  82 }
  83
  84
  85 /*
  86  * computes the checksum of the TCP/UDP pseudo-header
  87  * returns a 16-bit checksum, already complemented
  88  */
  89
  90 static inline unsigned int
  91 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
  92                   unsigned short proto, unsigned int sum)
  93 {
  94         __asm__ ("addl  %1,%0\n\t"
  95                  "addxl %4,%0\n\t"
  96                  "addxl %5,%0\n\t"
  97                  "clrl %1\n\t"
  98                  "addxl %1,%0"
  99                  : "=&d" (sum), "=&d" (saddr)
 100                  : "0" (daddr), "1" (saddr), "d" (len + proto),
 101                    "d"(sum));
 102         return sum;
 103 }
 104
 105 static inline unsigned short int
 106 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len,
 107                   unsigned short proto, unsigned int sum)
 108 {
 109         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 110 }
 111
 112 /*
 113  * this routine is used for miscellaneous IP-like checksums, mainly
 114  * in icmp.c
 115  */
 116
 117 static inline unsigned short
 118 ip_compute_csum(unsigned char * buff, int len)
 119 {
 120         return csum_fold (csum_partial(buff, len, 0));
 121 }
 122
 123 #define _HAVE_ARCH_IPV6_CSUM
 124 static __inline__ unsigned short int
 125 csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr,
 126                 __u16 len, unsigned short proto, unsigned int sum)
 127 {
 128         register unsigned long tmp;
 129         __asm__("addl %2@,%0\n\t"
 130                 "movel %2@(4),%1\n\t"
 131                 "addxl %1,%0\n\t"
 132                 "movel %2@(8),%1\n\t"
 133                 "addxl %1,%0\n\t"
 134                 "movel %2@(12),%1\n\t"
 135                 "addxl %1,%0\n\t"
 136                 "movel %3@,%1\n\t"
 137                 "addxl %1,%0\n\t"
 138                 "movel %3@(4),%1\n\t"
 139                 "addxl %1,%0\n\t"
 140                 "movel %3@(8),%1\n\t"
 141                 "addxl %1,%0\n\t"
 142                 "movel %3@(12),%1\n\t"
 143                 "addxl %1,%0\n\t"
 144                 "addxl %4,%0\n\t"
 145                 "clrl %1\n\t"
 146                 "addxl %1,%0"
 147                 : "=&d" (sum), "=&d" (tmp)
 148                 : "a" (saddr), "a" (daddr), "d" ((__u32) len + proto),
 149                   "0" (sum));
 150
 151         return csum_fold(sum);
 152 }
 153
 154 #endif /* _M68K_CHECKSUM_H */