/* * 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 <linux/sys.h> #include <asm/processor.h> #include <asm/errno.h> #include <asm/ppc_asm.h> .text /* * ip_fast_csum(buf, len) -- Optimized for IP header * len is in words and is always >= 5. */ _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 */ 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(saddr, daddr, len, proto, sum) */ _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 addze r0,r0 /* add in final carry */ 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) * * csum_partial(buff, len, sum) */ _GLOBAL(csum_partial) addic r0,r5,0 subi r3,r3,4 srwi. r6,r4,2 beq 3f /* if we're doing < 4 bytes */ andi. r5,r3,2 /* Align buffer to longword boundary */ beq+ 1f lhz r5,4(r3) /* do 2 bytes to get aligned */ addi r3,r3,2 subi r4,r4,2 addc r0,r0,r5 srwi. r6,r4,2 /* # words to do */ beq 3f 1: mtctr r6 2: lwzu r5,4(r3) /* the bdnz has zero overhead, so it should */ adde r0,r0,r5 /* be unnecessary to unroll this loop */ bdnz 2b andi. r4,r4,3 3: cmpwi 0,r4,2 blt+ 4f lhz r5,4(r3) addi r3,r3,2 subi r4,r4,2 adde r0,r0,r5 4: cmpwi 0,r4,1 bne+ 5f lbz r5,4(r3) slwi r5,r5,8 /* Upper byte of word */ adde r0,r0,r5 5: addze r3,r0 /* add in final carry */ 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. * * csum_partial_copy_generic(src, dst, len, sum, src_err, 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: srwi. r6,r5,4 /* # groups of 4 words to do */ beq 10f mtctr r6 71: lwz r6,4(r3) 72: lwz r9,8(r3) 73: lwz r10,12(r3) 74: lwzu r11,16(r3) adde r0,r0,r6 75: stw r6,4(r4) adde r0,r0,r9 76: stw r9,8(r4) adde r0,r0,r10 77: stw r10,12(r4) adde r0,r0,r11 78: stwu r11,16(r4) bdnz 71b 10: rlwinm. r6,r5,30,30,31 /* # words left to do */ beq 13f mtctr r6 82: lwzu r9,4(r3) 92: stwu r9,4(r4) adde r0,r0,r9 bdnz 82b 13: andi. r5,r5,3 3: cmpwi 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: cmpwi 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 */ blr /* These shouldn't go in the fixup section, since that would cause the ex_table addresses to get out of order. */ src_error_4: mfctr r6 /* update # bytes remaining from ctr */ rlwimi r5,r6,4,0,27 b 79f src_error_1: li r6,0 subi r5,r5,2 95: sth r6,4(r4) addi r4,r4,2 79: srwi. r6,r5,2 beq 3f mtctr r6 src_error_2: li r6,0 96: stwu r6,4(r4) bdnz 96b 3: andi. r5,r5,3 beq src_error src_error_3: li r6,0 mtctr r5 addi r4,r4,3 97: stbu r6,1(r4) bdnz 97b src_error: cmpwi 0,r7,0 beq 1f li r6,-EFAULT stw r6,0(r7) 1: addze r3,r0 blr dst_error: cmpwi 0,r8,0 beq 1f li r6,-EFAULT stw r6,0(r8) 1: addze r3,r0 blr .section __ex_table,"a" .long 81b,src_error_1 .long 91b,dst_error .long 71b,src_error_4 .long 72b,src_error_4 .long 73b,src_error_4 .long 74b,src_error_4 .long 75b,dst_error .long 76b,dst_error .long 77b,dst_error .long 78b,dst_error .long 82b,src_error_2 .long 92b,dst_error .long 83b,src_error_3 .long 93b,dst_error .long 84b,src_error_3 .long 94b,dst_error .long 95b,dst_error .long 96b,dst_error .long 97b,dst_error