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/* $Id: csum_partial.S,v 1.1 1998/05/04 09:12:52 ralf Exp $
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1998 Ralf Baechle
*/
#include <asm/asm.h>
#include <asm/regdef.h>
#define ADDC(sum,reg) \
addu sum, reg; \
sltu v1, sum, reg; \
addu sum, v1
#define CSUM_BIGCHUNK(src, offset, sum, t0, t1, t2, t3) \
lw t0, (offset + 0x00)(src); \
lw t1, (offset + 0x04)(src); \
lw t2, (offset + 0x08)(src); \
lw t3, (offset + 0x0c)(src); \
ADDC(sum, t0); \
ADDC(sum, t1); \
ADDC(sum, t2); \
ADDC(sum, t3); \
lw t0, (offset + 0x10)(src); \
lw t1, (offset + 0x14)(src); \
lw t2, (offset + 0x18)(src); \
lw t3, (offset + 0x1c)(src); \
ADDC(sum, t0); \
ADDC(sum, t1); \
ADDC(sum, t2); \
ADDC(sum, t3); \
/*
* a0: source address
* a1: length of the area to checksum
* a2: partial checksum
*/
#define src a0
#define dest a1
#define sum v0
.text
.set noreorder
/* unknown src alignment and < 8 bytes to go */
small_csumcpy:
move a1, t2
andi t0, a1, 4
beqz t0, 1f
andi t0, a1, 2
/* Still a full word to go */
ulw t1, (src)
addiu src, 4
ADDC(sum, t1)
1: move t1, zero
beqz t0, 1f
andi t0, a1, 1
/* Still a halfword to go */
ulhu t1, (src)
addiu src, 2
1: beqz t0, 1f
sll t1, t1, 16
lbu t2, (src)
nop
#ifdef __MIPSEB__
sll t2, t2, 8
#endif
or t1, t2
1: ADDC(sum, t1)
/* fold checksum */
sll v1, sum, 16
addu sum, v1
sltu v1, sum, v1
srl sum, sum, 16
addu sum, v1
/* odd buffer alignment? */
beqz t7, 1f
nop
sll v1, sum, 8
srl sum, sum, 8
or sum, v1
andi sum, 0xffff
1:
.set reorder
/* Add the passed partial csum. */
ADDC(sum, a2)
jr ra
.set noreorder
/* ------------------------------------------------------------------------- */
.align 5
LEAF(csum_partial)
move sum, zero
move t7, zero
sltiu t8, a1, 0x8
bnez t8, small_csumcpy /* < 8 bytes to copy */
move t2, a1
beqz a1, out
andi t7, src, 0x1 /* odd buffer? */
hword_align:
beqz t7, word_align
andi t8, src, 0x2
lbu t0, (src)
subu a1, a1, 0x1
#ifdef __MIPSEL__
sll t0, t0, 8
#endif
ADDC(sum, t0)
addu src, src, 0x1
andi t8, src, 0x2
word_align:
beqz t8, dword_align
sltiu t8, a1, 56
lhu t0, (src)
subu a1, a1, 0x2
ADDC(sum, t0)
sltiu t8, a1, 56
addu src, src, 0x2
dword_align:
bnez t8, do_end_words
move t8, a1
andi t8, src, 0x4
beqz t8, qword_align
andi t8, src, 0x8
lw t0, 0x00(src)
subu a1, a1, 0x4
ADDC(sum, t0)
addu src, src, 0x4
andi t8, src, 0x8
qword_align:
beqz t8, oword_align
andi t8, src, 0x10
lw t0, 0x00(src)
lw t1, 0x04(src)
subu a1, a1, 0x8
ADDC(sum, t0)
ADDC(sum, t1)
addu src, src, 0x8
andi t8, src, 0x10
oword_align:
beqz t8, begin_movement
srl t8, a1, 0x7
lw t3, 0x08(src)
lw t4, 0x0c(src)
lw t0, 0x00(src)
lw t1, 0x04(src)
ADDC(sum, t3)
ADDC(sum, t4)
ADDC(sum, t0)
ADDC(sum, t1)
subu a1, a1, 0x10
addu src, src, 0x10
srl t8, a1, 0x7
begin_movement:
beqz t8, 1f
andi t2, a1, 0x40
move_128bytes:
CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
CSUM_BIGCHUNK(src, 0x20, sum, t0, t1, t3, t4)
CSUM_BIGCHUNK(src, 0x40, sum, t0, t1, t3, t4)
CSUM_BIGCHUNK(src, 0x60, sum, t0, t1, t3, t4)
subu t8, t8, 0x01
bnez t8, move_128bytes
addu src, src, 0x80
1:
beqz t2, 1f
andi t2, a1, 0x20
move_64bytes:
CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
CSUM_BIGCHUNK(src, 0x20, sum, t0, t1, t3, t4)
addu src, src, 0x40
1:
beqz t2, do_end_words
andi t8, a1, 0x1c
move_32bytes:
CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
andi t8, a1, 0x1c
addu src, src, 0x20
do_end_words:
beqz t8, maybe_end_cruft
srl t8, t8, 0x2
end_words:
lw t0, (src)
subu t8, t8, 0x1
ADDC(sum, t0)
bnez t8, end_words
addu src, src, 0x4
maybe_end_cruft:
andi t2, a1, 0x3
small_memcpy:
j small_csumcpy; move a1, t2
beqz t2, out
move a1, t2
end_bytes:
lb t0, (src)
subu a1, a1, 0x1
bnez a2, end_bytes
addu src, src, 0x1
out:
jr ra
move v0, sum
END(csum_partial)
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