332 lines
6.7 KiB
ArmAsm
332 lines
6.7 KiB
ArmAsm
/*
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* linux/arch/arm/lib/csumpartialcopygeneric.S
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*
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* Copyright (C) 1995-2001 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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/*
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* unsigned int
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* csum_partial_copy_xxx(const char *src, char *dst, int len, int sum, )
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* r0 = src, r1 = dst, r2 = len, r3 = sum
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* Returns : r0 = checksum
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*
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* Note that 'tst' and 'teq' preserve the carry flag.
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*/
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src .req r0
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dst .req r1
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len .req r2
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sum .req r3
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.zero: mov r0, sum
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load_regs ea
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/*
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* Align an unaligned destination pointer. We know that
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* we have >= 8 bytes here, so we don't need to check
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* the length. Note that the source pointer hasn't been
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* aligned yet.
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*/
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.dst_unaligned: tst dst, #1
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beq .dst_16bit
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load1b ip
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sub len, len, #1
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adcs sum, sum, ip, put_byte_1 @ update checksum
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strb ip, [dst], #1
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tst dst, #2
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moveq pc, lr @ dst is now 32bit aligned
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.dst_16bit: load2b r8, ip
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sub len, len, #2
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adcs sum, sum, r8, put_byte_0
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strb r8, [dst], #1
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adcs sum, sum, ip, put_byte_1
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strb ip, [dst], #1
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mov pc, lr @ dst is now 32bit aligned
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/*
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* Handle 0 to 7 bytes, with any alignment of source and
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* destination pointers. Note that when we get here, C = 0
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*/
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.less8: teq len, #0 @ check for zero count
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beq .zero
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/* we must have at least one byte. */
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tst dst, #1 @ dst 16-bit aligned
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beq .less8_aligned
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/* Align dst */
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load1b ip
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sub len, len, #1
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adcs sum, sum, ip, put_byte_1 @ update checksum
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strb ip, [dst], #1
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tst len, #6
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beq .less8_byteonly
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1: load2b r8, ip
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sub len, len, #2
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adcs sum, sum, r8, put_byte_0
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strb r8, [dst], #1
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adcs sum, sum, ip, put_byte_1
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strb ip, [dst], #1
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.less8_aligned: tst len, #6
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bne 1b
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.less8_byteonly:
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tst len, #1
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beq .done
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load1b r8
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adcs sum, sum, r8, put_byte_0 @ update checksum
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strb r8, [dst], #1
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b .done
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FN_ENTRY
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mov ip, sp
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save_regs
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sub fp, ip, #4
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cmp len, #8 @ Ensure that we have at least
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blo .less8 @ 8 bytes to copy.
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adds sum, sum, #0 @ C = 0
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tst dst, #3 @ Test destination alignment
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blne .dst_unaligned @ align destination, return here
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/*
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* Ok, the dst pointer is now 32bit aligned, and we know
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* that we must have more than 4 bytes to copy. Note
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* that C contains the carry from the dst alignment above.
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*/
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tst src, #3 @ Test source alignment
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bne .src_not_aligned
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/* Routine for src & dst aligned */
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bics ip, len, #15
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beq 2f
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1: load4l r4, r5, r6, r7
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stmia dst!, {r4, r5, r6, r7}
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adcs sum, sum, r4
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adcs sum, sum, r5
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adcs sum, sum, r6
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adcs sum, sum, r7
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sub ip, ip, #16
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teq ip, #0
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bne 1b
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2: ands ip, len, #12
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beq 4f
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tst ip, #8
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beq 3f
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load2l r4, r5
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stmia dst!, {r4, r5}
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adcs sum, sum, r4
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adcs sum, sum, r5
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tst ip, #4
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beq 4f
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3: load1l r4
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str r4, [dst], #4
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adcs sum, sum, r4
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4: ands len, len, #3
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beq .done
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load1l r4
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tst len, #2
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mov r5, r4, get_byte_0
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beq .exit
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adcs sum, sum, r4, push #16
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strb r5, [dst], #1
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mov r5, r4, get_byte_1
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strb r5, [dst], #1
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mov r5, r4, get_byte_2
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.exit: tst len, #1
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strneb r5, [dst], #1
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andne r5, r5, #255
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adcnes sum, sum, r5, put_byte_0
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/*
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* If the dst pointer was not 16-bit aligned, we
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* need to rotate the checksum here to get around
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* the inefficient byte manipulations in the
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* architecture independent code.
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*/
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.done: adc r0, sum, #0
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ldr sum, [sp, #0] @ dst
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tst sum, #1
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movne r0, r0, ror #8
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load_regs ea
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.src_not_aligned:
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adc sum, sum, #0 @ include C from dst alignment
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and ip, src, #3
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bic src, src, #3
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load1l r5
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cmp ip, #2
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beq .src2_aligned
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bhi .src3_aligned
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mov r4, r5, pull #8 @ C = 0
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bics ip, len, #15
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beq 2f
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1: load4l r5, r6, r7, r8
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orr r4, r4, r5, push #24
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mov r5, r5, pull #8
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orr r5, r5, r6, push #24
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mov r6, r6, pull #8
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orr r6, r6, r7, push #24
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mov r7, r7, pull #8
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orr r7, r7, r8, push #24
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stmia dst!, {r4, r5, r6, r7}
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adcs sum, sum, r4
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adcs sum, sum, r5
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adcs sum, sum, r6
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adcs sum, sum, r7
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mov r4, r8, pull #8
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sub ip, ip, #16
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teq ip, #0
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bne 1b
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2: ands ip, len, #12
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beq 4f
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tst ip, #8
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beq 3f
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load2l r5, r6
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orr r4, r4, r5, push #24
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mov r5, r5, pull #8
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orr r5, r5, r6, push #24
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stmia dst!, {r4, r5}
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adcs sum, sum, r4
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adcs sum, sum, r5
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mov r4, r6, pull #8
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tst ip, #4
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beq 4f
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3: load1l r5
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orr r4, r4, r5, push #24
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str r4, [dst], #4
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adcs sum, sum, r4
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mov r4, r5, pull #8
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4: ands len, len, #3
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beq .done
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mov r5, r4, get_byte_0
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tst len, #2
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beq .exit
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adcs sum, sum, r4, push #16
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strb r5, [dst], #1
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mov r5, r4, get_byte_1
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strb r5, [dst], #1
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mov r5, r4, get_byte_2
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b .exit
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.src2_aligned: mov r4, r5, pull #16
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adds sum, sum, #0
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bics ip, len, #15
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beq 2f
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1: load4l r5, r6, r7, r8
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orr r4, r4, r5, push #16
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mov r5, r5, pull #16
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orr r5, r5, r6, push #16
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mov r6, r6, pull #16
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orr r6, r6, r7, push #16
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mov r7, r7, pull #16
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orr r7, r7, r8, push #16
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stmia dst!, {r4, r5, r6, r7}
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adcs sum, sum, r4
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adcs sum, sum, r5
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adcs sum, sum, r6
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adcs sum, sum, r7
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mov r4, r8, pull #16
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sub ip, ip, #16
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teq ip, #0
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bne 1b
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2: ands ip, len, #12
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beq 4f
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tst ip, #8
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beq 3f
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load2l r5, r6
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orr r4, r4, r5, push #16
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mov r5, r5, pull #16
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orr r5, r5, r6, push #16
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stmia dst!, {r4, r5}
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adcs sum, sum, r4
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adcs sum, sum, r5
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mov r4, r6, pull #16
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tst ip, #4
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beq 4f
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3: load1l r5
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orr r4, r4, r5, push #16
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str r4, [dst], #4
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adcs sum, sum, r4
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mov r4, r5, pull #16
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4: ands len, len, #3
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beq .done
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mov r5, r4, get_byte_0
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tst len, #2
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beq .exit
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adcs sum, sum, r4
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strb r5, [dst], #1
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mov r5, r4, get_byte_1
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strb r5, [dst], #1
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tst len, #1
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beq .done
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load1b r5
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b .exit
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.src3_aligned: mov r4, r5, pull #24
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adds sum, sum, #0
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bics ip, len, #15
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beq 2f
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1: load4l r5, r6, r7, r8
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orr r4, r4, r5, push #8
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mov r5, r5, pull #24
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orr r5, r5, r6, push #8
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mov r6, r6, pull #24
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orr r6, r6, r7, push #8
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mov r7, r7, pull #24
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orr r7, r7, r8, push #8
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stmia dst!, {r4, r5, r6, r7}
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adcs sum, sum, r4
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adcs sum, sum, r5
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adcs sum, sum, r6
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adcs sum, sum, r7
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mov r4, r8, pull #24
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sub ip, ip, #16
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teq ip, #0
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bne 1b
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2: ands ip, len, #12
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beq 4f
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tst ip, #8
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beq 3f
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load2l r5, r6
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orr r4, r4, r5, push #8
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mov r5, r5, pull #24
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orr r5, r5, r6, push #8
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stmia dst!, {r4, r5}
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adcs sum, sum, r4
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adcs sum, sum, r5
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mov r4, r6, pull #24
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tst ip, #4
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beq 4f
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3: load1l r5
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orr r4, r4, r5, push #8
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str r4, [dst], #4
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adcs sum, sum, r4
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mov r4, r5, pull #24
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4: ands len, len, #3
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beq .done
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mov r5, r4, get_byte_0
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tst len, #2
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beq .exit
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strb r5, [dst], #1
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adcs sum, sum, r4
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load1l r4
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mov r5, r4, get_byte_0
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strb r5, [dst], #1
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adcs sum, sum, r4, push #24
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mov r5, r4, get_byte_1
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b .exit
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