mirror of https://gitee.com/openkylin/linux.git
757 lines
16 KiB
ArmAsm
757 lines
16 KiB
ArmAsm
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Quick'n'dirty IP checksum ...
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*
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* Copyright (C) 1998, 1999 Ralf Baechle
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* Copyright (C) 1999 Silicon Graphics, Inc.
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* Copyright (C) 2007 Maciej W. Rozycki
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*/
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#include <linux/errno.h>
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#include <asm/asm.h>
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#include <asm/asm-offsets.h>
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#include <asm/regdef.h>
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#ifdef CONFIG_64BIT
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/*
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* As we are sharing code base with the mips32 tree (which use the o32 ABI
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* register definitions). We need to redefine the register definitions from
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* the n64 ABI register naming to the o32 ABI register naming.
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*/
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#undef t0
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#undef t1
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#undef t2
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#undef t3
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#define t0 $8
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#define t1 $9
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#define t2 $10
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#define t3 $11
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#define t4 $12
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#define t5 $13
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#define t6 $14
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#define t7 $15
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#define USE_DOUBLE
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#endif
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#ifdef USE_DOUBLE
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#define LOAD ld
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#define ADD daddu
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#define NBYTES 8
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#else
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#define LOAD lw
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#define ADD addu
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#define NBYTES 4
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#endif /* USE_DOUBLE */
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#define UNIT(unit) ((unit)*NBYTES)
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#define ADDC(sum,reg) \
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.set push; \
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.set noat; \
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ADD sum, reg; \
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sltu v1, sum, reg; \
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ADD sum, v1; \
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.set pop
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#define CSUM_BIGCHUNK1(src, offset, sum, _t0, _t1, _t2, _t3) \
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LOAD _t0, (offset + UNIT(0))(src); \
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LOAD _t1, (offset + UNIT(1))(src); \
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LOAD _t2, (offset + UNIT(2))(src); \
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LOAD _t3, (offset + UNIT(3))(src); \
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ADDC(sum, _t0); \
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ADDC(sum, _t1); \
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ADDC(sum, _t2); \
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ADDC(sum, _t3)
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#ifdef USE_DOUBLE
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#define CSUM_BIGCHUNK(src, offset, sum, _t0, _t1, _t2, _t3) \
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CSUM_BIGCHUNK1(src, offset, sum, _t0, _t1, _t2, _t3)
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#else
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#define CSUM_BIGCHUNK(src, offset, sum, _t0, _t1, _t2, _t3) \
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CSUM_BIGCHUNK1(src, offset, sum, _t0, _t1, _t2, _t3); \
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CSUM_BIGCHUNK1(src, offset + 0x10, sum, _t0, _t1, _t2, _t3)
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#endif
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/*
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* a0: source address
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* a1: length of the area to checksum
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* a2: partial checksum
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*/
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#define src a0
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#define sum v0
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.text
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.set noreorder
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.align 5
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LEAF(csum_partial)
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move sum, zero
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move t7, zero
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sltiu t8, a1, 0x8
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bnez t8, .Lsmall_csumcpy /* < 8 bytes to copy */
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move t2, a1
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andi t7, src, 0x1 /* odd buffer? */
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.Lhword_align:
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beqz t7, .Lword_align
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andi t8, src, 0x2
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lbu t0, (src)
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LONG_SUBU a1, a1, 0x1
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#ifdef __MIPSEL__
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sll t0, t0, 8
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#endif
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ADDC(sum, t0)
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PTR_ADDU src, src, 0x1
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andi t8, src, 0x2
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.Lword_align:
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beqz t8, .Ldword_align
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sltiu t8, a1, 56
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lhu t0, (src)
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LONG_SUBU a1, a1, 0x2
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ADDC(sum, t0)
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sltiu t8, a1, 56
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PTR_ADDU src, src, 0x2
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.Ldword_align:
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bnez t8, .Ldo_end_words
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move t8, a1
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andi t8, src, 0x4
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beqz t8, .Lqword_align
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andi t8, src, 0x8
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lw t0, 0x00(src)
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LONG_SUBU a1, a1, 0x4
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ADDC(sum, t0)
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PTR_ADDU src, src, 0x4
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andi t8, src, 0x8
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.Lqword_align:
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beqz t8, .Loword_align
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andi t8, src, 0x10
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#ifdef USE_DOUBLE
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ld t0, 0x00(src)
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LONG_SUBU a1, a1, 0x8
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ADDC(sum, t0)
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#else
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lw t0, 0x00(src)
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lw t1, 0x04(src)
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LONG_SUBU a1, a1, 0x8
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ADDC(sum, t0)
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ADDC(sum, t1)
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#endif
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PTR_ADDU src, src, 0x8
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andi t8, src, 0x10
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.Loword_align:
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beqz t8, .Lbegin_movement
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LONG_SRL t8, a1, 0x7
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#ifdef USE_DOUBLE
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ld t0, 0x00(src)
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ld t1, 0x08(src)
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ADDC(sum, t0)
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ADDC(sum, t1)
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#else
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CSUM_BIGCHUNK1(src, 0x00, sum, t0, t1, t3, t4)
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#endif
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LONG_SUBU a1, a1, 0x10
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PTR_ADDU src, src, 0x10
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LONG_SRL t8, a1, 0x7
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.Lbegin_movement:
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beqz t8, 1f
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andi t2, a1, 0x40
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.Lmove_128bytes:
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CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
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CSUM_BIGCHUNK(src, 0x20, sum, t0, t1, t3, t4)
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CSUM_BIGCHUNK(src, 0x40, sum, t0, t1, t3, t4)
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CSUM_BIGCHUNK(src, 0x60, sum, t0, t1, t3, t4)
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LONG_SUBU t8, t8, 0x01
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.set reorder /* DADDI_WAR */
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PTR_ADDU src, src, 0x80
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bnez t8, .Lmove_128bytes
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.set noreorder
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1:
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beqz t2, 1f
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andi t2, a1, 0x20
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.Lmove_64bytes:
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CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
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CSUM_BIGCHUNK(src, 0x20, sum, t0, t1, t3, t4)
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PTR_ADDU src, src, 0x40
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1:
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beqz t2, .Ldo_end_words
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andi t8, a1, 0x1c
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.Lmove_32bytes:
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CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
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andi t8, a1, 0x1c
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PTR_ADDU src, src, 0x20
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.Ldo_end_words:
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beqz t8, .Lsmall_csumcpy
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andi t2, a1, 0x3
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LONG_SRL t8, t8, 0x2
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.Lend_words:
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lw t0, (src)
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LONG_SUBU t8, t8, 0x1
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ADDC(sum, t0)
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.set reorder /* DADDI_WAR */
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PTR_ADDU src, src, 0x4
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bnez t8, .Lend_words
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.set noreorder
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/* unknown src alignment and < 8 bytes to go */
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.Lsmall_csumcpy:
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move a1, t2
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andi t0, a1, 4
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beqz t0, 1f
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andi t0, a1, 2
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/* Still a full word to go */
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ulw t1, (src)
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PTR_ADDIU src, 4
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ADDC(sum, t1)
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1: move t1, zero
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beqz t0, 1f
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andi t0, a1, 1
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/* Still a halfword to go */
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ulhu t1, (src)
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PTR_ADDIU src, 2
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1: beqz t0, 1f
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sll t1, t1, 16
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lbu t2, (src)
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nop
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#ifdef __MIPSEB__
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sll t2, t2, 8
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#endif
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or t1, t2
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1: ADDC(sum, t1)
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/* fold checksum */
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.set push
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.set noat
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#ifdef USE_DOUBLE
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dsll32 v1, sum, 0
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daddu sum, v1
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sltu v1, sum, v1
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dsra32 sum, sum, 0
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addu sum, v1
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#endif
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sll v1, sum, 16
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addu sum, v1
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sltu v1, sum, v1
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srl sum, sum, 16
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addu sum, v1
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/* odd buffer alignment? */
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beqz t7, 1f
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nop
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sll v1, sum, 8
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srl sum, sum, 8
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or sum, v1
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andi sum, 0xffff
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.set pop
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1:
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.set reorder
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/* Add the passed partial csum. */
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ADDC(sum, a2)
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jr ra
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.set noreorder
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END(csum_partial)
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/*
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* checksum and copy routines based on memcpy.S
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*
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* csum_partial_copy_nocheck(src, dst, len, sum)
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* __csum_partial_copy_user(src, dst, len, sum, errp)
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*
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* See "Spec" in memcpy.S for details. Unlike __copy_user, all
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* function in this file use the standard calling convention.
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*/
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#define src a0
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#define dst a1
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#define len a2
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#define psum a3
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#define sum v0
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#define odd t8
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#define errptr t9
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/*
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* The exception handler for loads requires that:
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* 1- AT contain the address of the byte just past the end of the source
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* of the copy,
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* 2- src_entry <= src < AT, and
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* 3- (dst - src) == (dst_entry - src_entry),
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* The _entry suffix denotes values when __copy_user was called.
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*
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* (1) is set up up by __csum_partial_copy_from_user and maintained by
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* not writing AT in __csum_partial_copy
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* (2) is met by incrementing src by the number of bytes copied
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* (3) is met by not doing loads between a pair of increments of dst and src
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*
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* The exception handlers for stores stores -EFAULT to errptr and return.
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* These handlers do not need to overwrite any data.
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*/
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#define EXC(inst_reg,addr,handler) \
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9: inst_reg, addr; \
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.section __ex_table,"a"; \
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PTR 9b, handler; \
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.previous
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#ifdef USE_DOUBLE
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#define LOAD ld
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#define LOADL ldl
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#define LOADR ldr
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#define STOREL sdl
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#define STORER sdr
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#define STORE sd
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#define ADD daddu
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#define SUB dsubu
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#define SRL dsrl
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#define SLL dsll
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#define SLLV dsllv
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#define SRLV dsrlv
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#define NBYTES 8
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#define LOG_NBYTES 3
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#else
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#define LOAD lw
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#define LOADL lwl
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#define LOADR lwr
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#define STOREL swl
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#define STORER swr
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#define STORE sw
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#define ADD addu
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#define SUB subu
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#define SRL srl
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#define SLL sll
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#define SLLV sllv
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#define SRLV srlv
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#define NBYTES 4
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#define LOG_NBYTES 2
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#endif /* USE_DOUBLE */
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#ifdef CONFIG_CPU_LITTLE_ENDIAN
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#define LDFIRST LOADR
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#define LDREST LOADL
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#define STFIRST STORER
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#define STREST STOREL
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#define SHIFT_DISCARD SLLV
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#define SHIFT_DISCARD_REVERT SRLV
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#else
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#define LDFIRST LOADL
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#define LDREST LOADR
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#define STFIRST STOREL
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#define STREST STORER
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#define SHIFT_DISCARD SRLV
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#define SHIFT_DISCARD_REVERT SLLV
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#endif
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#define FIRST(unit) ((unit)*NBYTES)
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#define REST(unit) (FIRST(unit)+NBYTES-1)
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#define ADDRMASK (NBYTES-1)
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#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
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.set noat
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#else
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.set at=v1
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#endif
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LEAF(__csum_partial_copy_user)
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PTR_ADDU AT, src, len /* See (1) above. */
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#ifdef CONFIG_64BIT
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move errptr, a4
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#else
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lw errptr, 16(sp)
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#endif
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FEXPORT(csum_partial_copy_nocheck)
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move sum, zero
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move odd, zero
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/*
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* Note: dst & src may be unaligned, len may be 0
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* Temps
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*/
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/*
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* The "issue break"s below are very approximate.
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* Issue delays for dcache fills will perturb the schedule, as will
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* load queue full replay traps, etc.
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*
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* If len < NBYTES use byte operations.
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*/
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sltu t2, len, NBYTES
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and t1, dst, ADDRMASK
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bnez t2, .Lcopy_bytes_checklen
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and t0, src, ADDRMASK
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andi odd, dst, 0x1 /* odd buffer? */
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bnez t1, .Ldst_unaligned
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nop
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bnez t0, .Lsrc_unaligned_dst_aligned
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/*
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* use delay slot for fall-through
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* src and dst are aligned; need to compute rem
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*/
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.Lboth_aligned:
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SRL t0, len, LOG_NBYTES+3 # +3 for 8 units/iter
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beqz t0, .Lcleanup_both_aligned # len < 8*NBYTES
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nop
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SUB len, 8*NBYTES # subtract here for bgez loop
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.align 4
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1:
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EXC( LOAD t0, UNIT(0)(src), .Ll_exc)
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EXC( LOAD t1, UNIT(1)(src), .Ll_exc_copy)
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EXC( LOAD t2, UNIT(2)(src), .Ll_exc_copy)
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EXC( LOAD t3, UNIT(3)(src), .Ll_exc_copy)
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EXC( LOAD t4, UNIT(4)(src), .Ll_exc_copy)
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EXC( LOAD t5, UNIT(5)(src), .Ll_exc_copy)
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EXC( LOAD t6, UNIT(6)(src), .Ll_exc_copy)
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EXC( LOAD t7, UNIT(7)(src), .Ll_exc_copy)
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SUB len, len, 8*NBYTES
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ADD src, src, 8*NBYTES
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EXC( STORE t0, UNIT(0)(dst), .Ls_exc)
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ADDC(sum, t0)
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EXC( STORE t1, UNIT(1)(dst), .Ls_exc)
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ADDC(sum, t1)
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EXC( STORE t2, UNIT(2)(dst), .Ls_exc)
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ADDC(sum, t2)
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EXC( STORE t3, UNIT(3)(dst), .Ls_exc)
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ADDC(sum, t3)
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EXC( STORE t4, UNIT(4)(dst), .Ls_exc)
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ADDC(sum, t4)
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EXC( STORE t5, UNIT(5)(dst), .Ls_exc)
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ADDC(sum, t5)
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EXC( STORE t6, UNIT(6)(dst), .Ls_exc)
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ADDC(sum, t6)
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EXC( STORE t7, UNIT(7)(dst), .Ls_exc)
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ADDC(sum, t7)
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.set reorder /* DADDI_WAR */
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ADD dst, dst, 8*NBYTES
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bgez len, 1b
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.set noreorder
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ADD len, 8*NBYTES # revert len (see above)
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/*
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* len == the number of bytes left to copy < 8*NBYTES
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*/
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.Lcleanup_both_aligned:
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#define rem t7
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beqz len, .Ldone
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sltu t0, len, 4*NBYTES
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bnez t0, .Lless_than_4units
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and rem, len, (NBYTES-1) # rem = len % NBYTES
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/*
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* len >= 4*NBYTES
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*/
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EXC( LOAD t0, UNIT(0)(src), .Ll_exc)
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EXC( LOAD t1, UNIT(1)(src), .Ll_exc_copy)
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EXC( LOAD t2, UNIT(2)(src), .Ll_exc_copy)
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EXC( LOAD t3, UNIT(3)(src), .Ll_exc_copy)
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SUB len, len, 4*NBYTES
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ADD src, src, 4*NBYTES
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EXC( STORE t0, UNIT(0)(dst), .Ls_exc)
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ADDC(sum, t0)
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EXC( STORE t1, UNIT(1)(dst), .Ls_exc)
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ADDC(sum, t1)
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EXC( STORE t2, UNIT(2)(dst), .Ls_exc)
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ADDC(sum, t2)
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EXC( STORE t3, UNIT(3)(dst), .Ls_exc)
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ADDC(sum, t3)
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.set reorder /* DADDI_WAR */
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ADD dst, dst, 4*NBYTES
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beqz len, .Ldone
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.set noreorder
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.Lless_than_4units:
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/*
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* rem = len % NBYTES
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*/
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beq rem, len, .Lcopy_bytes
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nop
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1:
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EXC( LOAD t0, 0(src), .Ll_exc)
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ADD src, src, NBYTES
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SUB len, len, NBYTES
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EXC( STORE t0, 0(dst), .Ls_exc)
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ADDC(sum, t0)
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.set reorder /* DADDI_WAR */
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|
ADD dst, dst, NBYTES
|
|
bne rem, len, 1b
|
|
.set noreorder
|
|
|
|
/*
|
|
* src and dst are aligned, need to copy rem bytes (rem < NBYTES)
|
|
* A loop would do only a byte at a time with possible branch
|
|
* mispredicts. Can't do an explicit LOAD dst,mask,or,STORE
|
|
* because can't assume read-access to dst. Instead, use
|
|
* STREST dst, which doesn't require read access to dst.
|
|
*
|
|
* This code should perform better than a simple loop on modern,
|
|
* wide-issue mips processors because the code has fewer branches and
|
|
* more instruction-level parallelism.
|
|
*/
|
|
#define bits t2
|
|
beqz len, .Ldone
|
|
ADD t1, dst, len # t1 is just past last byte of dst
|
|
li bits, 8*NBYTES
|
|
SLL rem, len, 3 # rem = number of bits to keep
|
|
EXC( LOAD t0, 0(src), .Ll_exc)
|
|
SUB bits, bits, rem # bits = number of bits to discard
|
|
SHIFT_DISCARD t0, t0, bits
|
|
EXC( STREST t0, -1(t1), .Ls_exc)
|
|
SHIFT_DISCARD_REVERT t0, t0, bits
|
|
.set reorder
|
|
ADDC(sum, t0)
|
|
b .Ldone
|
|
.set noreorder
|
|
.Ldst_unaligned:
|
|
/*
|
|
* dst is unaligned
|
|
* t0 = src & ADDRMASK
|
|
* t1 = dst & ADDRMASK; T1 > 0
|
|
* len >= NBYTES
|
|
*
|
|
* Copy enough bytes to align dst
|
|
* Set match = (src and dst have same alignment)
|
|
*/
|
|
#define match rem
|
|
EXC( LDFIRST t3, FIRST(0)(src), .Ll_exc)
|
|
ADD t2, zero, NBYTES
|
|
EXC( LDREST t3, REST(0)(src), .Ll_exc_copy)
|
|
SUB t2, t2, t1 # t2 = number of bytes copied
|
|
xor match, t0, t1
|
|
EXC( STFIRST t3, FIRST(0)(dst), .Ls_exc)
|
|
SLL t4, t1, 3 # t4 = number of bits to discard
|
|
SHIFT_DISCARD t3, t3, t4
|
|
/* no SHIFT_DISCARD_REVERT to handle odd buffer properly */
|
|
ADDC(sum, t3)
|
|
beq len, t2, .Ldone
|
|
SUB len, len, t2
|
|
ADD dst, dst, t2
|
|
beqz match, .Lboth_aligned
|
|
ADD src, src, t2
|
|
|
|
.Lsrc_unaligned_dst_aligned:
|
|
SRL t0, len, LOG_NBYTES+2 # +2 for 4 units/iter
|
|
beqz t0, .Lcleanup_src_unaligned
|
|
and rem, len, (4*NBYTES-1) # rem = len % 4*NBYTES
|
|
1:
|
|
/*
|
|
* Avoid consecutive LD*'s to the same register since some mips
|
|
* implementations can't issue them in the same cycle.
|
|
* It's OK to load FIRST(N+1) before REST(N) because the two addresses
|
|
* are to the same unit (unless src is aligned, but it's not).
|
|
*/
|
|
EXC( LDFIRST t0, FIRST(0)(src), .Ll_exc)
|
|
EXC( LDFIRST t1, FIRST(1)(src), .Ll_exc_copy)
|
|
SUB len, len, 4*NBYTES
|
|
EXC( LDREST t0, REST(0)(src), .Ll_exc_copy)
|
|
EXC( LDREST t1, REST(1)(src), .Ll_exc_copy)
|
|
EXC( LDFIRST t2, FIRST(2)(src), .Ll_exc_copy)
|
|
EXC( LDFIRST t3, FIRST(3)(src), .Ll_exc_copy)
|
|
EXC( LDREST t2, REST(2)(src), .Ll_exc_copy)
|
|
EXC( LDREST t3, REST(3)(src), .Ll_exc_copy)
|
|
ADD src, src, 4*NBYTES
|
|
#ifdef CONFIG_CPU_SB1
|
|
nop # improves slotting
|
|
#endif
|
|
EXC( STORE t0, UNIT(0)(dst), .Ls_exc)
|
|
ADDC(sum, t0)
|
|
EXC( STORE t1, UNIT(1)(dst), .Ls_exc)
|
|
ADDC(sum, t1)
|
|
EXC( STORE t2, UNIT(2)(dst), .Ls_exc)
|
|
ADDC(sum, t2)
|
|
EXC( STORE t3, UNIT(3)(dst), .Ls_exc)
|
|
ADDC(sum, t3)
|
|
.set reorder /* DADDI_WAR */
|
|
ADD dst, dst, 4*NBYTES
|
|
bne len, rem, 1b
|
|
.set noreorder
|
|
|
|
.Lcleanup_src_unaligned:
|
|
beqz len, .Ldone
|
|
and rem, len, NBYTES-1 # rem = len % NBYTES
|
|
beq rem, len, .Lcopy_bytes
|
|
nop
|
|
1:
|
|
EXC( LDFIRST t0, FIRST(0)(src), .Ll_exc)
|
|
EXC( LDREST t0, REST(0)(src), .Ll_exc_copy)
|
|
ADD src, src, NBYTES
|
|
SUB len, len, NBYTES
|
|
EXC( STORE t0, 0(dst), .Ls_exc)
|
|
ADDC(sum, t0)
|
|
.set reorder /* DADDI_WAR */
|
|
ADD dst, dst, NBYTES
|
|
bne len, rem, 1b
|
|
.set noreorder
|
|
|
|
.Lcopy_bytes_checklen:
|
|
beqz len, .Ldone
|
|
nop
|
|
.Lcopy_bytes:
|
|
/* 0 < len < NBYTES */
|
|
#ifdef CONFIG_CPU_LITTLE_ENDIAN
|
|
#define SHIFT_START 0
|
|
#define SHIFT_INC 8
|
|
#else
|
|
#define SHIFT_START 8*(NBYTES-1)
|
|
#define SHIFT_INC -8
|
|
#endif
|
|
move t2, zero # partial word
|
|
li t3, SHIFT_START # shift
|
|
/* use .Ll_exc_copy here to return correct sum on fault */
|
|
#define COPY_BYTE(N) \
|
|
EXC( lbu t0, N(src), .Ll_exc_copy); \
|
|
SUB len, len, 1; \
|
|
EXC( sb t0, N(dst), .Ls_exc); \
|
|
SLLV t0, t0, t3; \
|
|
addu t3, SHIFT_INC; \
|
|
beqz len, .Lcopy_bytes_done; \
|
|
or t2, t0
|
|
|
|
COPY_BYTE(0)
|
|
COPY_BYTE(1)
|
|
#ifdef USE_DOUBLE
|
|
COPY_BYTE(2)
|
|
COPY_BYTE(3)
|
|
COPY_BYTE(4)
|
|
COPY_BYTE(5)
|
|
#endif
|
|
EXC( lbu t0, NBYTES-2(src), .Ll_exc_copy)
|
|
SUB len, len, 1
|
|
EXC( sb t0, NBYTES-2(dst), .Ls_exc)
|
|
SLLV t0, t0, t3
|
|
or t2, t0
|
|
.Lcopy_bytes_done:
|
|
ADDC(sum, t2)
|
|
.Ldone:
|
|
/* fold checksum */
|
|
.set push
|
|
.set noat
|
|
#ifdef USE_DOUBLE
|
|
dsll32 v1, sum, 0
|
|
daddu sum, v1
|
|
sltu v1, sum, v1
|
|
dsra32 sum, sum, 0
|
|
addu sum, v1
|
|
#endif
|
|
sll v1, sum, 16
|
|
addu sum, v1
|
|
sltu v1, sum, v1
|
|
srl sum, sum, 16
|
|
addu sum, v1
|
|
|
|
/* odd buffer alignment? */
|
|
beqz odd, 1f
|
|
nop
|
|
sll v1, sum, 8
|
|
srl sum, sum, 8
|
|
or sum, v1
|
|
andi sum, 0xffff
|
|
.set pop
|
|
1:
|
|
.set reorder
|
|
ADDC(sum, psum)
|
|
jr ra
|
|
.set noreorder
|
|
|
|
.Ll_exc_copy:
|
|
/*
|
|
* Copy bytes from src until faulting load address (or until a
|
|
* lb faults)
|
|
*
|
|
* When reached by a faulting LDFIRST/LDREST, THREAD_BUADDR($28)
|
|
* may be more than a byte beyond the last address.
|
|
* Hence, the lb below may get an exception.
|
|
*
|
|
* Assumes src < THREAD_BUADDR($28)
|
|
*/
|
|
LOAD t0, TI_TASK($28)
|
|
li t2, SHIFT_START
|
|
LOAD t0, THREAD_BUADDR(t0)
|
|
1:
|
|
EXC( lbu t1, 0(src), .Ll_exc)
|
|
ADD src, src, 1
|
|
sb t1, 0(dst) # can't fault -- we're copy_from_user
|
|
SLLV t1, t1, t2
|
|
addu t2, SHIFT_INC
|
|
ADDC(sum, t1)
|
|
.set reorder /* DADDI_WAR */
|
|
ADD dst, dst, 1
|
|
bne src, t0, 1b
|
|
.set noreorder
|
|
.Ll_exc:
|
|
LOAD t0, TI_TASK($28)
|
|
nop
|
|
LOAD t0, THREAD_BUADDR(t0) # t0 is just past last good address
|
|
nop
|
|
SUB len, AT, t0 # len number of uncopied bytes
|
|
/*
|
|
* Here's where we rely on src and dst being incremented in tandem,
|
|
* See (3) above.
|
|
* dst += (fault addr - src) to put dst at first byte to clear
|
|
*/
|
|
ADD dst, t0 # compute start address in a1
|
|
SUB dst, src
|
|
/*
|
|
* Clear len bytes starting at dst. Can't call __bzero because it
|
|
* might modify len. An inefficient loop for these rare times...
|
|
*/
|
|
.set reorder /* DADDI_WAR */
|
|
SUB src, len, 1
|
|
beqz len, .Ldone
|
|
.set noreorder
|
|
1: sb zero, 0(dst)
|
|
ADD dst, dst, 1
|
|
.set push
|
|
.set noat
|
|
#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
|
|
bnez src, 1b
|
|
SUB src, src, 1
|
|
#else
|
|
li v1, 1
|
|
bnez src, 1b
|
|
SUB src, src, v1
|
|
#endif
|
|
li v1, -EFAULT
|
|
b .Ldone
|
|
sw v1, (errptr)
|
|
|
|
.Ls_exc:
|
|
li v0, -1 /* invalid checksum */
|
|
li v1, -EFAULT
|
|
jr ra
|
|
sw v1, (errptr)
|
|
.set pop
|
|
END(__csum_partial_copy_user)
|