kernel-ark/arch/mn10300/lib/do_csum.S
David Howells b920de1b77 mn10300: add the MN10300/AM33 architecture to the kernel
Add architecture support for the MN10300/AM33 CPUs produced by MEI to the
kernel.

This patch also adds board support for the ASB2303 with the ASB2308 daughter
board, and the ASB2305.  The only processor supported is the MN103E010, which
is an AM33v2 core plus on-chip devices.

[akpm@linux-foundation.org: nuke cvs control strings]
Signed-off-by: Masakazu Urade <urade.masakazu@jp.panasonic.com>
Signed-off-by: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:30 -08:00

163 lines
2.9 KiB
ArmAsm

/* Optimised simple memory checksum
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <asm/cache.h>
.section .text
.balign L1_CACHE_BYTES
###############################################################################
#
# unsigned int do_csum(const unsigned char *buff, size_t len)
#
###############################################################################
.globl do_csum
.type do_csum,@function
do_csum:
movm [d2,d3],(sp)
mov d0,(12,sp)
mov d1,(16,sp)
mov d1,d2 # count
mov d0,a0 # buff
clr d1 # accumulator
cmp +0,d2
beq do_csum_done # return if zero-length buffer
# 4-byte align the buffer pointer
btst +3,a0
beq do_csum_now_4b_aligned
btst +1,a0
beq do_csum_addr_not_odd
movbu (a0),d0
inc a0
asl +8,d0
add d0,d1
addc +0,d1
add -1,d2
do_csum_addr_not_odd:
cmp +2,d2
bcs do_csum_fewer_than_4
btst +2,a0
beq do_csum_now_4b_aligned
movhu (a0+),d0
add d0,d1
addc +0,d1
add -2,d2
cmp +4,d2
bcs do_csum_fewer_than_4
do_csum_now_4b_aligned:
# we want to checksum as much as we can in chunks of 32 bytes
cmp +31,d2
bls do_csum_remainder # 4-byte aligned remainder
add -32,d2
mov +32,d3
do_csum_loop:
mov (a0+),d0
add d0,d1
mov (a0+),e0
addc e0,d1
mov (a0+),e1
addc e1,d1
mov (a0+),e3
addc e3,d1
mov (a0+),d0
addc d0,d1
mov (a0+),e0
addc e0,d1
mov (a0+),e1
addc e1,d1
mov (a0+),e3
addc e3,d1
addc +0,d1
sub d3,d2
bcc do_csum_loop
add d3,d2
beq do_csum_done
do_csum_remainder:
# cut 16-31 bytes down to 0-15
cmp +16,d2
bcs do_csum_fewer_than_16
mov (a0+),d0
add d0,d1
mov (a0+),e0
addc e0,d1
mov (a0+),e1
addc e1,d1
mov (a0+),e3
addc e3,d1
addc +0,d1
add -16,d2
beq do_csum_done
do_csum_fewer_than_16:
# copy the remaining whole words
cmp +4,d2
bcs do_csum_fewer_than_4
cmp +8,d2
bcs do_csum_one_word
cmp +12,d2
bcs do_csum_two_words
mov (a0+),d0
add d0,d1
addc +0,d1
do_csum_two_words:
mov (a0+),d0
add d0,d1
addc +0,d1
do_csum_one_word:
mov (a0+),d0
add d0,d1
addc +0,d1
do_csum_fewer_than_4:
and +3,d2
beq do_csum_done
xor_cmp d0,d0,+2,d2
bcs do_csum_fewer_than_2
movhu (a0+),d0
do_csum_fewer_than_2:
and +1,d2
beq do_csum_add_last_bit
movbu (a0),d3
add d3,d0
do_csum_add_last_bit:
add d0,d1
addc +0,d1
do_csum_done:
# compress the checksum down to 16 bits
mov +0xffff0000,d2
and d1,d2
asl +16,d1
add d2,d1,d0
addc +0xffff,d0
lsr +16,d0
# flip the halves of the word result if the buffer was oddly aligned
mov (12,sp),d1
and +1,d1
beq do_csum_not_oddly_aligned
swaph d0,d0 # exchange bits 15:8 with 7:0
do_csum_not_oddly_aligned:
ret [d2,d3],8
do_csum_end:
.size do_csum, do_csum_end-do_csum