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![Chris Metcalf](/assets/img/avatar_default.png)
The toolchain supports big-endian mode now, so add support for building the kernel to run big-endian as well. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
239 lines
5.5 KiB
C
239 lines
5.5 KiB
C
/*
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* Copyright 2011 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/module.h>
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/* EXPORT_SYMBOL() is in arch/tile/lib/exports.c since this should be asm. */
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/* Must be 8 bytes in size. */
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#define word_t uint64_t
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#if CHIP_L2_LINE_SIZE() != 64 && CHIP_L2_LINE_SIZE() != 128
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#error "Assumes 64 or 128 byte line size"
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#endif
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/* How many cache lines ahead should we prefetch? */
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#define PREFETCH_LINES_AHEAD 3
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/*
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* Provide "base versions" of load and store for the normal code path.
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* The kernel provides other versions for userspace copies.
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*/
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#define ST(p, v) (*(p) = (v))
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#define LD(p) (*(p))
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#ifndef USERCOPY_FUNC
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#define ST1 ST
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#define ST2 ST
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#define ST4 ST
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#define ST8 ST
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#define LD1 LD
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#define LD2 LD
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#define LD4 LD
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#define LD8 LD
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#define RETVAL dstv
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void *memcpy(void *__restrict dstv, const void *__restrict srcv, size_t n)
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#else
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/*
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* Special kernel version will provide implementation of the LDn/STn
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* macros to return a count of uncopied bytes due to mm fault.
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*/
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#define RETVAL 0
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int USERCOPY_FUNC(void *__restrict dstv, const void *__restrict srcv, size_t n)
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#endif
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{
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char *__restrict dst1 = (char *)dstv;
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const char *__restrict src1 = (const char *)srcv;
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const char *__restrict src1_end;
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const char *__restrict prefetch;
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word_t *__restrict dst8; /* 8-byte pointer to destination memory. */
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word_t final; /* Final bytes to write to trailing word, if any */
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long i;
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if (n < 16) {
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for (; n; n--)
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ST1(dst1++, LD1(src1++));
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return RETVAL;
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}
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/*
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* Locate the end of source memory we will copy. Don't
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* prefetch past this.
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*/
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src1_end = src1 + n - 1;
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/* Prefetch ahead a few cache lines, but not past the end. */
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prefetch = src1;
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for (i = 0; i < PREFETCH_LINES_AHEAD; i++) {
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__insn_prefetch(prefetch);
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prefetch += CHIP_L2_LINE_SIZE();
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prefetch = (prefetch > src1_end) ? prefetch : src1;
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}
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/* Copy bytes until dst is word-aligned. */
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for (; (uintptr_t)dst1 & (sizeof(word_t) - 1); n--)
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ST1(dst1++, LD1(src1++));
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/* 8-byte pointer to destination memory. */
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dst8 = (word_t *)dst1;
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if (__builtin_expect((uintptr_t)src1 & (sizeof(word_t) - 1), 0)) {
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/*
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* Misaligned copy. Copy 8 bytes at a time, but don't
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* bother with other fanciness.
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*
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* TODO: Consider prefetching and using wh64 as well.
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*/
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/* Create an aligned src8. */
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const word_t *__restrict src8 =
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(const word_t *)((uintptr_t)src1 & -sizeof(word_t));
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word_t b;
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word_t a = LD8(src8++);
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for (; n >= sizeof(word_t); n -= sizeof(word_t)) {
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b = LD8(src8++);
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a = __insn_dblalign(a, b, src1);
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ST8(dst8++, a);
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a = b;
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}
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if (n == 0)
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return RETVAL;
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b = ((const char *)src8 <= src1_end) ? *src8 : 0;
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/*
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* Final source bytes to write to trailing partial
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* word, if any.
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*/
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final = __insn_dblalign(a, b, src1);
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} else {
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/* Aligned copy. */
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const word_t* __restrict src8 = (const word_t *)src1;
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/* src8 and dst8 are both word-aligned. */
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if (n >= CHIP_L2_LINE_SIZE()) {
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/* Copy until 'dst' is cache-line-aligned. */
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for (; (uintptr_t)dst8 & (CHIP_L2_LINE_SIZE() - 1);
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n -= sizeof(word_t))
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ST8(dst8++, LD8(src8++));
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for (; n >= CHIP_L2_LINE_SIZE(); ) {
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__insn_wh64(dst8);
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/*
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* Prefetch and advance to next line
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* to prefetch, but don't go past the end
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*/
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__insn_prefetch(prefetch);
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prefetch += CHIP_L2_LINE_SIZE();
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prefetch = (prefetch > src1_end) ? prefetch :
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(const char *)src8;
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/*
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* Copy an entire cache line. Manually
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* unrolled to avoid idiosyncracies of
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* compiler unrolling.
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*/
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#define COPY_WORD(offset) ({ ST8(dst8+offset, LD8(src8+offset)); n -= 8; })
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COPY_WORD(0);
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COPY_WORD(1);
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COPY_WORD(2);
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COPY_WORD(3);
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COPY_WORD(4);
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COPY_WORD(5);
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COPY_WORD(6);
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COPY_WORD(7);
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#if CHIP_L2_LINE_SIZE() == 128
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COPY_WORD(8);
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COPY_WORD(9);
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COPY_WORD(10);
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COPY_WORD(11);
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COPY_WORD(12);
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COPY_WORD(13);
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COPY_WORD(14);
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COPY_WORD(15);
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#elif CHIP_L2_LINE_SIZE() != 64
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# error Fix code that assumes particular L2 cache line sizes
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#endif
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dst8 += CHIP_L2_LINE_SIZE() / sizeof(word_t);
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src8 += CHIP_L2_LINE_SIZE() / sizeof(word_t);
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}
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}
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for (; n >= sizeof(word_t); n -= sizeof(word_t))
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ST8(dst8++, LD8(src8++));
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if (__builtin_expect(n == 0, 1))
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return RETVAL;
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final = LD8(src8);
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}
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/* n != 0 if we get here. Write out any trailing bytes. */
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dst1 = (char *)dst8;
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#ifndef __BIG_ENDIAN__
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if (n & 4) {
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ST4((uint32_t *)dst1, final);
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dst1 += 4;
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final >>= 32;
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n &= 3;
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}
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if (n & 2) {
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ST2((uint16_t *)dst1, final);
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dst1 += 2;
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final >>= 16;
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n &= 1;
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}
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if (n)
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ST1((uint8_t *)dst1, final);
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#else
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if (n & 4) {
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ST4((uint32_t *)dst1, final >> 32);
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dst1 += 4;
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}
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else
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{
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final >>= 32;
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}
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if (n & 2) {
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ST2((uint16_t *)dst1, final >> 16);
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dst1 += 2;
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}
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else
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{
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final >>= 16;
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}
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if (n & 1)
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ST1((uint8_t *)dst1, final >> 8);
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#endif
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return RETVAL;
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}
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#ifdef USERCOPY_FUNC
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#undef ST1
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#undef ST2
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#undef ST4
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#undef ST8
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#undef LD1
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#undef LD2
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#undef LD4
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#undef LD8
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#undef USERCOPY_FUNC
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#endif
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