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/*
* 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 "../kernel/ppc_asm.tmpl"
.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: cmpi 0,r4,2
blt+ 4f
lhz r5,4(r3)
addi r3,r3,2
subi r4,r4,2
adde r0,r0,r5
4: cmpi 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: 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 */
blr
/* These shouldn't go in the fixup section, since that would
cause the ex_table addresses to get out of order. */
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
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:
cmpi 0,r7,0
beq 1f
li r6,-EFAULT
stw r6,0(r7)
1: addze r3,r0
blr
dst_error:
cmpi 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 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
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