243 строки
4.1 KiB
ArmAsm
243 строки
4.1 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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*/
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#include <asm/asm.h>
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#include <asm/regdef.h>
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#define ADDC(sum,reg) \
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addu sum, reg; \
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sltu v1, sum, reg; \
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addu sum, v1
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#define CSUM_BIGCHUNK(src, offset, sum, t0, t1, t2, t3) \
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lw t0, (offset + 0x00)(src); \
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lw t1, (offset + 0x04)(src); \
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lw t2, (offset + 0x08)(src); \
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lw t3, (offset + 0x0c)(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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lw t0, (offset + 0x10)(src); \
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lw t1, (offset + 0x14)(src); \
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lw t2, (offset + 0x18)(src); \
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lw t3, (offset + 0x1c)(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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/*
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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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/* unknown src alignment and < 8 bytes to go */
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small_csumcpy:
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move a1, ta2
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andi ta0, a1, 4
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beqz ta0, 1f
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andi ta0, a1, 2
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/* Still a full word to go */
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ulw ta1, (src)
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daddiu src, 4
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ADDC(sum, ta1)
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1: move ta1, zero
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beqz ta0, 1f
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andi ta0, a1, 1
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/* Still a halfword to go */
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ulhu ta1, (src)
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daddiu src, 2
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1: beqz ta0, 1f
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sll ta1, ta1, 16
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lbu ta2, (src)
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nop
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#ifdef __MIPSEB__
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sll ta2, ta2, 8
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#endif
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or ta1, ta2
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1: ADDC(sum, ta1)
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/* fold checksum */
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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 t3, 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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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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/* ------------------------------------------------------------------------- */
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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 t3, zero
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sltiu t8, a1, 0x8
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bnez t8, small_csumcpy /* < 8 bytes to copy */
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move ta2, a1
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beqz a1, out
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andi t3, src, 0x1 /* odd buffer? */
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hword_align:
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beqz t3, word_align
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andi t8, src, 0x2
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lbu ta0, (src)
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dsubu a1, a1, 0x1
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#ifdef __MIPSEL__
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sll ta0, ta0, 8
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#endif
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ADDC(sum, ta0)
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daddu src, src, 0x1
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andi t8, src, 0x2
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word_align:
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beqz t8, dword_align
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sltiu t8, a1, 56
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lhu ta0, (src)
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dsubu a1, a1, 0x2
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ADDC(sum, ta0)
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sltiu t8, a1, 56
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daddu src, src, 0x2
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dword_align:
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bnez t8, do_end_words
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move t8, a1
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andi t8, src, 0x4
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beqz t8, qword_align
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andi t8, src, 0x8
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lw ta0, 0x00(src)
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dsubu a1, a1, 0x4
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ADDC(sum, ta0)
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daddu src, src, 0x4
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andi t8, src, 0x8
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qword_align:
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beqz t8, oword_align
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andi t8, src, 0x10
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lw ta0, 0x00(src)
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lw ta1, 0x04(src)
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dsubu a1, a1, 0x8
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ADDC(sum, ta0)
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ADDC(sum, ta1)
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daddu src, src, 0x8
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andi t8, src, 0x10
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oword_align:
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beqz t8, begin_movement
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dsrl t8, a1, 0x7
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lw ta3, 0x08(src)
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lw t0, 0x0c(src)
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lw ta0, 0x00(src)
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lw ta1, 0x04(src)
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ADDC(sum, ta3)
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ADDC(sum, t0)
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ADDC(sum, ta0)
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ADDC(sum, ta1)
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dsubu a1, a1, 0x10
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daddu src, src, 0x10
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dsrl t8, a1, 0x7
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begin_movement:
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beqz t8, 1f
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andi ta2, a1, 0x40
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move_128bytes:
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CSUM_BIGCHUNK(src, 0x00, sum, ta0, ta1, ta3, t0)
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CSUM_BIGCHUNK(src, 0x20, sum, ta0, ta1, ta3, t0)
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CSUM_BIGCHUNK(src, 0x40, sum, ta0, ta1, ta3, t0)
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CSUM_BIGCHUNK(src, 0x60, sum, ta0, ta1, ta3, t0)
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dsubu t8, t8, 0x01
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bnez t8, move_128bytes
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daddu src, src, 0x80
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1:
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beqz ta2, 1f
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andi ta2, a1, 0x20
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move_64bytes:
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CSUM_BIGCHUNK(src, 0x00, sum, ta0, ta1, ta3, t0)
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CSUM_BIGCHUNK(src, 0x20, sum, ta0, ta1, ta3, t0)
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daddu src, src, 0x40
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1:
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beqz ta2, do_end_words
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andi t8, a1, 0x1c
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move_32bytes:
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CSUM_BIGCHUNK(src, 0x00, sum, ta0, ta1, ta3, t0)
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andi t8, a1, 0x1c
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daddu src, src, 0x20
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do_end_words:
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beqz t8, maybe_end_cruft
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dsrl t8, t8, 0x2
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end_words:
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lw ta0, (src)
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dsubu t8, t8, 0x1
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ADDC(sum, ta0)
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bnez t8, end_words
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daddu src, src, 0x4
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maybe_end_cruft:
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andi ta2, a1, 0x3
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small_memcpy:
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j small_csumcpy; move a1, ta2 /* XXX ??? */
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beqz t2, out
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move a1, ta2
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end_bytes:
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lb ta0, (src)
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dsubu a1, a1, 0x1
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bnez a2, end_bytes
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daddu src, src, 0x1
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out:
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jr ra
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move v0, sum
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END(csum_partial)
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