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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
434 lines
11 KiB
ArmAsm
434 lines
11 KiB
ArmAsm
/* Optimized version of the standard memcpy() function.
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This file is part of the GNU C Library.
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Copyright (C) 2000-2021 Free Software Foundation, Inc.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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/* Return: dest
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Inputs:
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in0: dest
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in1: src
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in2: byte count
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An assembly implementation of the algorithm used by the generic C
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version from glibc. The case when source and sest are aligned is
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treated separately, for extra performance.
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In this form, memcpy assumes little endian mode. For big endian mode,
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sh1 must be computed using an extra instruction: sub sh1 = 64, sh1
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and the order of r[MEMLAT] and r[MEMLAT+1] must be reverted in the
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shrp instruction. */
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#define USE_LFETCH
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#define USE_FLP
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#include <sysdep.h>
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#undef ret
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#define LFETCH_DIST 500
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#define ALIGN_UNROLL_no 4 // no. of elements
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#define ALIGN_UNROLL_sh 2 // (shift amount)
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#define MEMLAT 8
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#define Nrot ((4*(MEMLAT+2) + 7) & ~7)
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#define OP_T_THRES 16
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#define OPSIZ 8
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#define loopcnt r14
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#define elemcnt r15
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#define saved_pr r16
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#define saved_lc r17
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#define adest r18
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#define dest r19
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#define asrc r20
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#define src r21
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#define len r22
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#define tmp2 r23
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#define tmp3 r24
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#define tmp4 r25
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#define ptable r26
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#define ploop56 r27
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#define loopaddr r28
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#define sh1 r29
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#define ptr1 r30
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#define ptr2 r31
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#define movi0 mov
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#define p_scr p6
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#define p_xtr p7
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#define p_nxtr p8
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#define p_few p9
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#if defined(USE_FLP)
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#define load ldf8
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#define store stf8
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#define tempreg f6
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#define the_r fr
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#define the_s fs
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#define the_t ft
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#define the_q fq
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#define the_w fw
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#define the_x fx
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#define the_y fy
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#define the_z fz
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#elif defined(USE_INT)
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#define load ld8
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#define store st8
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#define tempreg tmp2
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#define the_r r
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#define the_s s
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#define the_t t
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#define the_q q
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#define the_w w
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#define the_x x
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#define the_y y
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#define the_z z
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#endif
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#ifdef GAS_ALIGN_BREAKS_UNWIND_INFO
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/* Manually force proper loop-alignment. Note: be sure to
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double-check the code-layout after making any changes to
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this routine! */
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# define ALIGN(n) { nop 0 }
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#else
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# define ALIGN(n) .align n
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#endif
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#if defined(USE_LFETCH)
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#define LOOP(shift) \
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ALIGN(32); \
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.loop##shift##: \
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{ .mmb \
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(p[0]) ld8.nt1 r[0] = [asrc], 8 ; \
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(p[0]) lfetch.nt1 [ptr1], 16 ; \
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nop.b 0 ; \
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} { .mib \
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(p[MEMLAT+1]) st8 [dest] = tmp3, 8 ; \
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(p[MEMLAT]) shrp tmp3 = r[MEMLAT], s[MEMLAT+1], shift ; \
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nop.b 0 ;; \
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} { .mmb \
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(p[0]) ld8.nt1 s[0] = [asrc], 8 ; \
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(p[0]) lfetch.nt1 [ptr2], 16 ; \
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nop.b 0 ; \
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} { .mib \
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(p[MEMLAT+1]) st8 [dest] = tmp4, 8 ; \
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(p[MEMLAT]) shrp tmp4 = s[MEMLAT], r[MEMLAT], shift ; \
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br.ctop.sptk.many .loop##shift \
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;; } \
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{ .mib \
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br.cond.sptk.many .copy_bytes ; /* deal with the remaining bytes */ \
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}
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#else
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#define LOOP(shift) \
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ALIGN(32); \
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.loop##shift##: \
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{ .mmb \
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(p[0]) ld8.nt1 r[0] = [asrc], 8 ; \
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nop.b 0 ; \
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} { .mib \
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(p[MEMLAT+1]) st8 [dest] = tmp3, 8 ; \
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(p[MEMLAT]) shrp tmp3 = r[MEMLAT], s[MEMLAT+1], shift ; \
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nop.b 0 ;; \
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} { .mmb \
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(p[0]) ld8.nt1 s[0] = [asrc], 8 ; \
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nop.b 0 ; \
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} { .mib \
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(p[MEMLAT+1]) st8 [dest] = tmp4, 8 ; \
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(p[MEMLAT]) shrp tmp4 = s[MEMLAT], r[MEMLAT], shift ; \
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br.ctop.sptk.many .loop##shift \
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;; } \
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{ .mib \
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br.cond.sptk.many .copy_bytes ; /* deal with the remaining bytes */ \
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}
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#endif
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ENTRY(memcpy)
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{ .mmi
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.prologue
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alloc r2 = ar.pfs, 3, Nrot - 3, 0, Nrot
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.rotr r[MEMLAT+1], s[MEMLAT+2], q[MEMLAT+1], t[MEMLAT+1]
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.rotp p[MEMLAT+2]
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.rotf fr[MEMLAT+1], fq[MEMLAT+1], fs[MEMLAT+1], ft[MEMLAT+1]
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mov ret0 = in0 // return tmp2 = dest
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.save pr, saved_pr
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movi0 saved_pr = pr // save the predicate registers
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} { .mmi
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and tmp4 = 7, in0 // check if destination is aligned
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mov dest = in0 // dest
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mov src = in1 // src
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;; }
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{ .mii
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cmp.eq p_scr, p0 = in2, r0 // if (len == 0)
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.save ar.lc, saved_lc
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movi0 saved_lc = ar.lc // save the loop counter
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.body
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cmp.ge p_few, p0 = OP_T_THRES, in2 // is len <= OP_T_THRESH
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} { .mbb
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mov len = in2 // len
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(p_scr) br.cond.dpnt.few .restore_and_exit // Branch no. 1: return dest
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(p_few) br.cond.dpnt.many .copy_bytes // Branch no. 2: copy byte by byte
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;; }
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{ .mmi
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#if defined(USE_LFETCH)
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lfetch.nt1 [dest] //
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lfetch.nt1 [src] //
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#endif
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shr.u elemcnt = len, 3 // elemcnt = len / 8
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} { .mib
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cmp.eq p_scr, p0 = tmp4, r0 // is destination aligned?
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sub loopcnt = 7, tmp4 //
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(p_scr) br.cond.dptk.many .dest_aligned
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;; }
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{ .mmi
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ld1 tmp2 = [src], 1 //
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sub len = len, loopcnt, 1 // reduce len
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movi0 ar.lc = loopcnt //
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} { .mib
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cmp.ne p_scr, p0 = 0, loopcnt // avoid loading beyond end-point
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;; }
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.l0: // ---------------------------- // L0: Align src on 8-byte boundary
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{ .mmi
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st1 [dest] = tmp2, 1 //
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(p_scr) ld1 tmp2 = [src], 1 //
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} { .mib
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cmp.lt p_scr, p0 = 1, loopcnt // avoid load beyond end-point
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add loopcnt = -1, loopcnt
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br.cloop.dptk.few .l0 //
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;; }
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.dest_aligned:
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{ .mmi
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and tmp4 = 7, src // ready for alignment check
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shr.u elemcnt = len, 3 // elemcnt = len / 8
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;; }
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{ .mib
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cmp.ne p_scr, p0 = tmp4, r0 // is source also aligned
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tbit.nz p_xtr, p_nxtr = src, 3 // prepare a separate move if src
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} { .mib // is not 16B aligned
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add ptr2 = LFETCH_DIST, dest // prefetch address
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add ptr1 = LFETCH_DIST, src
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(p_scr) br.cond.dptk.many .src_not_aligned
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;; }
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// The optimal case, when dest, and src are aligned
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.both_aligned:
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{ .mmi
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.pred.rel "mutex",p_xtr,p_nxtr
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(p_xtr) cmp.gt p_scr, p0 = ALIGN_UNROLL_no+1, elemcnt // Need N + 1 to qualify
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(p_nxtr) cmp.gt p_scr, p0 = ALIGN_UNROLL_no, elemcnt // Need only N to qualify
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movi0 pr.rot = 1 << 16 // set rotating predicates
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} { .mib
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(p_scr) br.cond.dpnt.many .copy_full_words
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;; }
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{ .mmi
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(p_xtr) load tempreg = [src], 8
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(p_xtr) add elemcnt = -1, elemcnt
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movi0 ar.ec = MEMLAT + 1 // set the epilog counter
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;; }
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{ .mmi
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(p_xtr) add len = -8, len //
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add asrc = 16, src // one bank apart (for USE_INT)
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shr.u loopcnt = elemcnt, ALIGN_UNROLL_sh // cater for unrolling
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;;}
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{ .mmi
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add loopcnt = -1, loopcnt
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(p_xtr) store [dest] = tempreg, 8 // copy the "extra" word
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nop.i 0
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;; }
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{ .mib
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add adest = 16, dest
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movi0 ar.lc = loopcnt // set the loop counter
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;; }
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#ifdef GAS_ALIGN_BREAKS_UNWIND_INFO
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{ nop 0 }
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#else
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.align 32
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#endif
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#if defined(USE_FLP)
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.l1: // ------------------------------- // L1: Everything a multiple of 8
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{ .mmi
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#if defined(USE_LFETCH)
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(p[0]) lfetch.nt1 [ptr2],32
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#endif
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(p[0]) ldfp8 the_r[0],the_q[0] = [src], 16
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(p[0]) add len = -32, len
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} {.mmb
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(p[MEMLAT]) store [dest] = the_r[MEMLAT], 8
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(p[MEMLAT]) store [adest] = the_s[MEMLAT], 8
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;; }
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{ .mmi
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#if defined(USE_LFETCH)
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(p[0]) lfetch.nt1 [ptr1],32
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#endif
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(p[0]) ldfp8 the_s[0], the_t[0] = [src], 16
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} {.mmb
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(p[MEMLAT]) store [dest] = the_q[MEMLAT], 24
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(p[MEMLAT]) store [adest] = the_t[MEMLAT], 24
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br.ctop.dptk.many .l1
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;; }
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#elif defined(USE_INT)
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.l1: // ------------------------------- // L1: Everything a multiple of 8
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{ .mmi
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(p[0]) load the_r[0] = [src], 8
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(p[0]) load the_q[0] = [asrc], 8
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(p[0]) add len = -32, len
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} {.mmb
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(p[MEMLAT]) store [dest] = the_r[MEMLAT], 8
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(p[MEMLAT]) store [adest] = the_q[MEMLAT], 8
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;; }
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{ .mmi
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(p[0]) load the_s[0] = [src], 24
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(p[0]) load the_t[0] = [asrc], 24
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} {.mmb
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(p[MEMLAT]) store [dest] = the_s[MEMLAT], 24
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(p[MEMLAT]) store [adest] = the_t[MEMLAT], 24
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#if defined(USE_LFETCH)
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;; }
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{ .mmb
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(p[0]) lfetch.nt1 [ptr2],32
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(p[0]) lfetch.nt1 [ptr1],32
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#endif
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br.ctop.dptk.many .l1
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;; }
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#endif
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.copy_full_words:
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{ .mib
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cmp.gt p_scr, p0 = 8, len //
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shr.u elemcnt = len, 3 //
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(p_scr) br.cond.dpnt.many .copy_bytes
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;; }
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{ .mii
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load tempreg = [src], 8
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add loopcnt = -1, elemcnt //
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;; }
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{ .mii
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cmp.ne p_scr, p0 = 0, loopcnt //
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mov ar.lc = loopcnt //
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;; }
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.l2: // ------------------------------- // L2: Max 4 words copied separately
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{ .mmi
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store [dest] = tempreg, 8
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(p_scr) load tempreg = [src], 8 //
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add len = -8, len
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} { .mib
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cmp.lt p_scr, p0 = 1, loopcnt // avoid load beyond end-point
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add loopcnt = -1, loopcnt
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br.cloop.dptk.few .l2
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;; }
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.copy_bytes:
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{ .mib
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cmp.eq p_scr, p0 = len, r0 // is len == 0 ?
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add loopcnt = -1, len // len--;
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(p_scr) br.cond.spnt .restore_and_exit
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;; }
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{ .mii
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ld1 tmp2 = [src], 1
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movi0 ar.lc = loopcnt
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cmp.ne p_scr, p0 = 0, loopcnt // avoid load beyond end-point
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;; }
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.l3: // ------------------------------- // L3: Final byte move
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{ .mmi
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st1 [dest] = tmp2, 1
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(p_scr) ld1 tmp2 = [src], 1
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} { .mib
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cmp.lt p_scr, p0 = 1, loopcnt // avoid load beyond end-point
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add loopcnt = -1, loopcnt
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br.cloop.dptk.few .l3
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;; }
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.restore_and_exit:
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{ .mmi
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movi0 pr = saved_pr, -1 // restore the predicate registers
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;; }
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{ .mib
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movi0 ar.lc = saved_lc // restore the loop counter
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br.ret.sptk.many b0
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;; }
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.src_not_aligned:
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{ .mmi
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cmp.gt p_scr, p0 = 16, len
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and sh1 = 7, src // sh1 = src % 8
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shr.u loopcnt = len, 4 // element-cnt = len / 16
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} { .mib
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add tmp4 = @ltoff(.table), gp
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add tmp3 = @ltoff(.loop56), gp
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(p_scr) br.cond.dpnt.many .copy_bytes // do byte by byte if too few
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;; }
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{ .mmi
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and asrc = -8, src // asrc = (-8) -- align src for loop
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add loopcnt = -1, loopcnt // loopcnt--
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shl sh1 = sh1, 3 // sh1 = 8 * (src % 8)
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} { .mmi
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ld8 ptable = [tmp4] // ptable = &table
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ld8 ploop56 = [tmp3] // ploop56 = &loop56
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and tmp2 = -16, len // tmp2 = len & -OPSIZ
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;; }
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{ .mmi
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add tmp3 = ptable, sh1 // tmp3 = &table + sh1
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add src = src, tmp2 // src += len & (-16)
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movi0 ar.lc = loopcnt // set LC
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;; }
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{ .mmi
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ld8 tmp4 = [tmp3] // tmp4 = loop offset
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sub len = len, tmp2 // len -= len & (-16)
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movi0 ar.ec = MEMLAT + 2 // one more pass needed
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;; }
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{ .mmi
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ld8 s[1] = [asrc], 8 // preload
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sub loopaddr = ploop56,tmp4 // loopadd = &loop56 - loop offset
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movi0 pr.rot = 1 << 16 // set rotating predicates
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;; }
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{ .mib
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nop.m 0
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movi0 b6 = loopaddr
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br b6 // jump to the appropriate loop
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;; }
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LOOP(8)
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LOOP(16)
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LOOP(24)
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LOOP(32)
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LOOP(40)
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LOOP(48)
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LOOP(56)
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END(memcpy)
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libc_hidden_builtin_def (memcpy)
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.rodata
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.align 8
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.table:
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data8 0 // dummy entry
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data8 .loop56 - .loop8
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data8 .loop56 - .loop16
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data8 .loop56 - .loop24
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data8 .loop56 - .loop32
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data8 .loop56 - .loop40
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data8 .loop56 - .loop48
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data8 .loop56 - .loop56
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