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/* $NetBSD: in_cksum_arm.S,v 1.2 2003/09/23 10:01:36 scw Exp $ */
/*-
* Copyright 2003 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Steve C. Woodford for Wasabi Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
/*
* Hand-optimised in_cksum() and in4_cksum() implementations for ARM/armv5e
*/
#include "opt_inet.h"
#include <machine/asm.h>
#include "assym.inc"
__FBSDID("$FreeBSD$");
.syntax unified
/*
* int in_cksum(struct mbuf *m, int len)
*
* Entry:
* r0 m
* r1 len
*
* NOTE: Assumes 'm' is *never* NULL.
*/
/* LINTSTUB: Func: int in_cksum(struct mbuf *, int) */
ENTRY(in_cksum)
stmfd sp!, {r4-r11,lr}
mov r8, #0x00
mov r9, r1
mov r10, #0x00
mov ip, r0
.Lin_cksum_loop:
ldr r1, [ip, #(M_LEN)]
ldr r0, [ip, #(M_DATA)]
ldr ip, [ip, #(M_NEXT)]
.Lin_cksum_entry4:
cmp r9, r1
movlt r1, r9
sub r9, r9, r1
eor r11, r10, r0
add r10, r10, r1
adds r2, r1, #0x00
blne _ASM_LABEL(L_cksumdata)
tst r11, #0x01
movne r2, r2, ror #8
adds r8, r8, r2
adc r8, r8, #0x00
cmp ip, #0x00
bne .Lin_cksum_loop
mov r1, #0xff
orr r1, r1, #0xff00
and r0, r8, r1
add r0, r0, r8, lsr #16
add r0, r0, r0, lsr #16
and r0, r0, r1
eor r0, r0, r1
ldmfd sp!, {r4-r11,pc}
END(in_cksum)
ENTRY(do_cksum)
stmfd sp!, {r4-r7, lr}
bl L_cksumdata
mov r0, r2
ldmfd sp!, {r4-r7, pc}
END(do_cksum)
/*
* The main in*_cksum() workhorse...
*
* Entry parameters:
* r0 Pointer to buffer
* r1 Buffer length
* lr Return address
*
* Returns:
* r2 Accumulated 32-bit sum
*
* Clobbers:
* r0-r7
*/
/* LINTSTUB: Ignore */
ASENTRY_NP(L_cksumdata)
pld [r0] /* Pre-fetch the start of the buffer */
mov r2, #0
/* We first have to word-align the buffer. */
ands r7, r0, #0x03
beq .Lcksumdata_wordaligned
rsb r7, r7, #0x04
cmp r1, r7 /* Enough bytes left to make it? */
blt .Lcksumdata_endgame
cmp r7, #0x02
ldrb r4, [r0], #0x01 /* Fetch 1st byte */
ldrbge r5, [r0], #0x01 /* Fetch 2nd byte */
movlt r5, #0x00
ldrbgt r6, [r0], #0x01 /* Fetch 3rd byte */
movle r6, #0x00
/* Combine the three bytes depending on endianness and alignment */
orreq r2, r4, r5, lsl #8
orreq r2, r2, r6, lsl #16
orrne r2, r5, r4, lsl #8
orrne r2, r2, r6, lsl #24
subs r1, r1, r7 /* Update length */
RETeq /* All done? */
/* Buffer is now word aligned */
.Lcksumdata_wordaligned:
cmp r1, #0x04 /* Less than 4 bytes left? */
blt .Lcksumdata_endgame /* Yup */
/* Now quad-align, if necessary */
ands r7, r0, #0x04
ldrne r7, [r0], #0x04
subne r1, r1, #0x04
subs r1, r1, #0x40
blt .Lcksumdata_bigloop_end /* Note: C flag clear if branch taken */
/*
* Buffer is now quad aligned. Sum 64 bytes at a time.
* Note: First ldrd is hoisted above the loop, together with
* setting r6 to zero to avoid stalling for results in the
* loop. (r7 is live, from above).
*/
ldrd r4, [r0], #0x08
mov r6, #0x00
.Lcksumdata_bigloop:
pld [r0, #0x18]
adds r2, r2, r6
adcs r2, r2, r7
ldrd r6, [r0], #0x08
adcs r2, r2, r4
adcs r2, r2, r5
ldrd r4, [r0], #0x08
adcs r2, r2, r6
adcs r2, r2, r7
ldrd r6, [r0], #0x08
adcs r2, r2, r4
adcs r2, r2, r5
ldrd r4, [r0], #0x08
adcs r2, r2, r6
adcs r2, r2, r7
pld [r0, #0x18]
ldrd r6, [r0], #0x08
adcs r2, r2, r4
adcs r2, r2, r5
ldrd r4, [r0], #0x08
adcs r2, r2, r6
adcs r2, r2, r7
ldrd r6, [r0], #0x08
adcs r2, r2, r4
adcs r2, r2, r5
adc r2, r2, #0x00
subs r1, r1, #0x40
ldrdge r4, [r0], #0x08
bge .Lcksumdata_bigloop
adds r2, r2, r6 /* r6/r7 still need summing */
.Lcksumdata_bigloop_end:
adcs r2, r2, r7
adc r2, r2, #0x00
adds r1, r1, #0x40
RETeq
cmp r1, #0x20
ldrdge r4, [r0], #0x08 /* Avoid stalling pld and result */
blt .Lcksumdata_less_than_32
pld [r0, #0x18]
ldrd r6, [r0], #0x08
adds r2, r2, r4
adcs r2, r2, r5
ldrd r4, [r0], #0x08
adcs r2, r2, r6
adcs r2, r2, r7
ldrd r6, [r0], #0x08
adcs r2, r2, r4
adcs r2, r2, r5
adcs r2, r2, r6 /* XXX: Unavoidable result stall */
adcs r2, r2, r7
adc r2, r2, #0x00
subs r1, r1, #0x20
RETeq
.Lcksumdata_less_than_32:
/* There are less than 32 bytes left */
and r3, r1, #0x18
rsb r4, r3, #0x18
sub r1, r1, r3
adds r4, r4, r4, lsr #1 /* Side effect: Clear carry flag */
addne pc, pc, r4
nop
/*
* Note: We use ldm here, even on armv5e, since the combined issue/result
* latencies for ldm and ldrd are the same. Using ldm avoids needless #ifdefs.
*/
/* At least 24 bytes remaining... */
ldmia r0!, {r4, r5}
adcs r2, r2, r4
adcs r2, r2, r5
/* At least 16 bytes remaining... */
ldmia r0!, {r4, r5}
adcs r2, r2, r4
adcs r2, r2, r5
/* At least 8 bytes remaining... */
ldmia r0!, {r4, r5}
adcs r2, r2, r4
adcs r2, r2, r5
/* Less than 8 bytes remaining... */
adc r2, r2, #0x00
subs r1, r1, #0x04
blt .Lcksumdata_lessthan4
ldr r4, [r0], #0x04
sub r1, r1, #0x04
adds r2, r2, r4
adc r2, r2, #0x00
/* Deal with < 4 bytes remaining */
.Lcksumdata_lessthan4:
adds r1, r1, #0x04
RETeq
/* Deal with 1 to 3 remaining bytes, possibly misaligned */
.Lcksumdata_endgame:
ldrb r3, [r0] /* Fetch first byte */
cmp r1, #0x02
ldrbge r4, [r0, #0x01] /* Fetch 2nd and 3rd as necessary */
movlt r4, #0x00
ldrbgt r5, [r0, #0x02]
movle r5, #0x00
/* Combine the three bytes depending on endianness and alignment */
tst r0, #0x01
orreq r3, r3, r4, lsl #8
orreq r3, r3, r5, lsl #16
orrne r3, r4, r3, lsl #8
orrne r3, r3, r5, lsl #24
adds r2, r2, r3
adc r2, r2, #0x00
RET
END(L_cksumdata)
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