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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [m68k/] [lib/] [checksum.c] - Rev 1782
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/* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * IP/TCP/UDP checksumming routines * * Authors: Jorge Cwik, <jorge@laser.satlink.net> * Arnt Gulbrandsen, <agulbra@nvg.unit.no> * Tom May, <ftom@netcom.com> * Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de> * Lots of code moved from tcp.c and ip.c; see those files * for more names. * * 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek: * Fixed some nasty bugs, causing some horrible crashes. * A: At some points, the sum (%0) was used as * length-counter instead of the length counter * (%1). Thanks to Roman Hodek for pointing this out. * B: GCC seems to mess up if one uses too many * data-registers to hold input values and one tries to * specify d0 and d1 as scratch registers. Letting gcc choose these * registers itself solves the problem. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <net/checksum.h> /* * computes a partial checksum, e.g. for TCP/UDP fragments */ unsigned int csum_partial (const unsigned char *buff, int len, unsigned int sum) { unsigned long tmp1, tmp2; /* * Experiments with ethernet and slip connections show that buff * is aligned on either a 2-byte or 4-byte boundary. */ __asm__("movel %2,%3\n\t" "btst #1,%3\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\t" "addw %2@+,%0\n\t" /* add first word to sum */ "clrl %3\n\t" "addxl %3,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%3\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "dbra %1,1b\n\t" "clrl %4\n\t" "addxl %4,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %3,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%3\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%3\n\t" "subqw #1,%3\n" "3:\t" /* loop for rest longs */ "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "dbra %3,3b\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %4\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "movew %2@+,%4\n\t" /* have rest >= 2: get word */ "swap %4\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\t" "moveb %2@,%4\n\t" /* have odd rest: get byte */ "lslw #8,%4\n\t" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %4,%0\n\t" /* now add rest long to sum */ "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "7:\t" : "=d" (sum), "=d" (len), "=a" (buff), "=&d" (tmp1), "=&d" (tmp2) : "0" (sum), "1" (len), "2" (buff) ); return(sum); } /* * copy from fs while checksumming, otherwise like csum_partial */ unsigned int csum_partial_copy_fromuser(const char *src, char *dst, int len, int sum) { unsigned long tmp1, tmp2; __asm__("movel %2,%4\n\t" "btst #1,%4\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\t" "movesw %2@+,%4\n\t" /* add first word to sum */ "addw %4,%0\n\t" "movew %4,%3@+\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%4\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %1,1b\n\t" "clrl %5\n\t" "addxl %5,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %4,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%4\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%4\n\t" "subqw #1,%4\n" "3:\t" /* loop for rest longs */ "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %4,3b\n\t" "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %5\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "movesw %2@+,%5\n\t" /* have rest >= 2: get word */ "movew %5,%3@+\n\t" "swap %5\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\t" "movesb %2@,%5\n\t" /* have odd rest: get byte */ "moveb %5,%3@+\n\t" "lslw #8,%5\n\t" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %5,%0\n\t" /* now add rest long to sum */ "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "7:\t" : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst), "=&d" (tmp1), "=&d" (tmp2) : "0" (sum), "1" (len), "2" (src), "3" (dst) ); return(sum); } /* * copy from ds while checksumming, otherwise like csum_partial */ unsigned int csum_partial_copy(const char *src, char *dst, int len, int sum) { unsigned long tmp1, tmp2; __asm__("movel %2,%4\n\t" "btst #1,%4\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\t" "movew %2@+,%4\n\t" /* add first word to sum */ "addw %4,%0\n\t" "movew %4,%3@+\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%4\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %1,1b\n\t" "clrl %5\n\t" "addxl %5,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %4,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%4\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%4\n\t" "subqw #1,%4\n" "3:\t" /* loop for rest longs */ "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %4,3b\n\t" "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %5\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "movew %2@+,%5\n\t" /* have rest >= 2: get word */ "movew %5,%3@+\n\t" "swap %5\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\t" "moveb %2@,%5\n\t" /* have odd rest: get byte */ "moveb %5,%3@+\n\t" "lslw #8,%5\n" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %5,%0\n\t" /* now add rest long to sum */ "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "7:\t" : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst), "=&d" (tmp1), "=&d" (tmp2) : "0" (sum), "1" (len), "2" (src), "3" (dst) ); return(sum); }