/* * This file contains assembly-language implementations * of IP-style 1's complement checksum routines. * * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) * * 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. * * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au). */ #include #include #include #include .text /* * ip_fast_csum(r3=buf, r4=len) -- Optimized for IP header * len is in words and is always >= 5. * * In practice len == 5, but this is not guaranteed. So this code does not * attempt to use doubleword instructions. */ _GLOBAL(ip_fast_csum) lwz r0,0(r3) lwzu r5,4(r3) addic. r4,r4,-2 addc r0,r0,r5 mtctr r4 blelr- 1: lwzu r4,4(r3) adde r0,r0,r4 bdnz 1b addze r0,r0 /* add in final carry */ rldicl r4,r0,32,0 /* fold two 32-bit halves together */ add r0,r0,r4 srdi r0,r0,32 rlwinm r3,r0,16,0,31 /* fold two halves together */ add r3,r0,r3 not r3,r3 srwi r3,r3,16 blr /* * Compute checksum of TCP or UDP pseudo-header: * csum_tcpudp_magic(r3=saddr, r4=daddr, r5=len, r6=proto, r7=sum) * No real gain trying to do this specially for 64 bit, but * the 32 bit addition may spill into the upper bits of * the doubleword so we still must fold it down from 64. */ _GLOBAL(csum_tcpudp_magic) rlwimi r5,r6,16,0,15 /* put proto in upper half of len */ addc r0,r3,r4 /* add 4 32-bit words together */ adde r0,r0,r5 adde r0,r0,r7 rldicl r4,r0,32,0 /* fold 64 bit value */ add r0,r4,r0 srdi r0,r0,32 rlwinm r3,r0,16,0,31 /* fold two halves together */ add r3,r0,r3 not r3,r3 srwi r3,r3,16 blr /* * Computes the checksum of a memory block at buff, length len, * and adds in "sum" (32-bit). * * This code assumes at least halfword alignment, though the length * can be any number of bytes. The sum is accumulated in r5. * * csum_partial(r3=buff, r4=len, r5=sum) */ _GLOBAL(csum_partial) subi r3,r3,8 /* we'll offset by 8 for the loads */ srdi. r6,r4,3 /* divide by 8 for doubleword count */ addic r5,r5,0 /* clear carry */ beq 3f /* if we're doing < 8 bytes */ andi. r0,r3,2 /* aligned on a word boundary already? */ beq+ 1f lhz r6,8(r3) /* do 2 bytes to get aligned */ addi r3,r3,2 subi r4,r4,2 addc r5,r5,r6 srdi. r6,r4,3 /* recompute number of doublewords */ beq 3f /* any left? */ 1: mtctr r6 2: ldu r6,8(r3) /* main sum loop */ adde r5,r5,r6 bdnz 2b andi. r4,r4,7 /* compute bytes left to sum after doublewords */ 3: cmpi 0,r4,4 /* is at least a full word left? */ blt 4f lwz r6,8(r3) /* sum this word */ addi r3,r3,4 subi r4,r4,4 adde r5,r5,r6 4: cmpi 0,r4,2 /* is at least a halfword left? */ blt+ 5f lhz r6,8(r3) /* sum this halfword */ addi r3,r3,2 subi r4,r4,2 adde r5,r5,r6 5: cmpi 0,r4,1 /* is at least a byte left? */ bne+ 6f lbz r6,8(r3) /* sum this byte */ slwi r6,r6,8 /* this byte is assumed to be the upper byte of a halfword */ adde r5,r5,r6 6: addze r5,r5 /* add in final carry */ rldicl r4,r5,32,0 /* fold two 32-bit halves together */ add r3,r4,r5 srdi r3,r3,32 blr /* * Computes the checksum of a memory block at src, length len, * and adds in "sum" (32-bit), while copying the block to dst. * If an access exception occurs on src or dst, it stores -EFAULT * to *src_err or *dst_err respectively, and (for an error on * src) zeroes the rest of dst. * * This code needs to be reworked to take advantage of 64 bit sum+copy. * However, due to tokenring halfword alignment problems this will be very * tricky. For now we'll leave it until we instrument it somehow. * * csum_partial_copy_generic(r3=src, r4=dst, r5=len, r6=sum, r7=src_err, r8=dst_err) */ _GLOBAL(csum_partial_copy_generic) addic r0,r6,0 subi r3,r3,4 subi r4,r4,4 srwi. r6,r5,2 beq 3f /* if we're doing < 4 bytes */ andi. r9,r4,2 /* Align dst to longword boundary */ beq+ 1f 81: lhz r6,4(r3) /* do 2 bytes to get aligned */ addi r3,r3,2 subi r5,r5,2 91: sth r6,4(r4) addi r4,r4,2 addc r0,r0,r6 srwi. r6,r5,2 /* # words to do */ beq 3f 1: mtctr r6 82: lwzu r6,4(r3) /* the bdnz has zero overhead, so it should */ 92: stwu r6,4(r4) /* be unnecessary to unroll this loop */ adde r0,r0,r6 bdnz 82b andi. r5,r5,3 3: cmpi 0,r5,2 blt+ 4f 83: lhz r6,4(r3) addi r3,r3,2 subi r5,r5,2 93: sth r6,4(r4) addi r4,r4,2 adde r0,r0,r6 4: cmpi 0,r5,1 bne+ 5f 84: lbz r6,4(r3) 94: stb r6,4(r4) slwi r6,r6,8 /* Upper byte of word */ adde r0,r0,r6 5: addze r3,r0 /* add in final carry (unlikely with 64-bit regs) */ rldicl r4,r3,32,0 /* fold 64 bit value */ add r3,r4,r3 srdi r3,r3,32 blr /* These shouldn't go in the fixup section, since that would cause the ex_table addresses to get out of order. */ .globl src_error_1 src_error_1: li r6,0 subi r5,r5,2 95: sth r6,4(r4) addi r4,r4,2 srwi. r6,r5,2 beq 3f mtctr r6 .globl src_error_2 src_error_2: li r6,0 96: stwu r6,4(r4) bdnz 96b 3: andi. r5,r5,3 beq src_error .globl src_error_3 src_error_3: li r6,0 mtctr r5 addi r4,r4,3 97: stbu r6,1(r4) bdnz 97b .globl src_error src_error: cmpi 0,r7,0 beq 1f li r6,-EFAULT stw r6,0(r7) 1: addze r3,r0 blr .globl dst_error dst_error: cmpi 0,r8,0 beq 1f li r6,-EFAULT stw r6,0(r8) 1: addze r3,r0 blr .section __ex_table,"a" .align 3 .llong 81b,src_error_1 .llong 91b,dst_error .llong 82b,src_error_2 .llong 92b,dst_error .llong 83b,src_error_3 .llong 93b,dst_error .llong 84b,src_error_3 .llong 94b,dst_error .llong 95b,dst_error .llong 96b,dst_error .llong 97b,dst_error