167 lines
5.0 KiB
ArmAsm
167 lines
5.0 KiB
ArmAsm
/* Optimized version of the memccpy() function.
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This file is part of the GNU C Library.
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Copyright (C) 2000, 2001 Free Software Foundation, Inc.
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Contributed by Dan Pop <Dan.Pop@cern.ch>.
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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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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/* Return: a pointer to the next byte after char in dest or NULL
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Inputs:
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in0: dest
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in1: src
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in2: char
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in3: byte count
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This implementation assumes little endian mode (UM.be = 0).
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This implementation assumes that it is safe to do read ahead
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in the src block, without getting beyond its limit. */
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#include <sysdep.h>
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#undef ret
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#define OP_T_THRES 16
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#define OPSIZ 8
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#define saved_pr r17
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#define saved_lc r18
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#define dest r19
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#define src r20
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#define len r21
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#define asrc r22
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#define tmp r23
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#define char r24
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#define charx8 r25
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#define sh2 r28
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#define sh1 r29
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#define loopcnt r30
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#define value r31
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ENTRY(memccpy)
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.prologue
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alloc r2 = ar.pfs, 4, 40 - 4, 0, 40
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#include "softpipe.h"
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.rotr r[MEMLAT + 3], tmp1[4], tmp2[4], val[4], tmp3[2], pos0[2]
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.rotp p[MEMLAT + 6 + 1]
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mov ret0 = r0 // return NULL if no match
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.save pr, saved_pr
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mov saved_pr = pr // save the predicate registers
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.save ar.lc, saved_lc
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mov saved_lc = ar.lc // save the loop counter
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.body
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mov dest = in0 // dest
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mov src = in1 // src
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extr.u char = in2, 0, 8 // char
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mov len = in3 // len
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sub tmp = r0, in0 // tmp = -dest
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cmp.ne p7, p0 = r0, r0 // clear p7
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;;
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and loopcnt = 7, tmp // loopcnt = -dest % 8
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cmp.ge p6, p0 = OP_T_THRES, len // is len <= OP_T_THRES
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(p6) br.cond.spnt .cpyfew // copy byte by byte
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;;
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cmp.eq p6, p0 = loopcnt, r0
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mux1 charx8 = char, @brcst
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(p6) br.cond.sptk .dest_aligned
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sub len = len, loopcnt // len -= -dest % 8
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adds loopcnt = -1, loopcnt // --loopcnt
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;;
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mov ar.lc = loopcnt
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.l1: // copy -dest % 8 bytes
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ld1 value = [src], 1 // value = *src++
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;;
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st1 [dest] = value, 1 // *dest++ = value
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cmp.eq p6, p0 = value, char
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(p6) br.cond.spnt .foundit
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br.cloop.dptk .l1
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.dest_aligned:
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and sh1 = 7, src // sh1 = src % 8
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and tmp = -8, len // tmp = len & -OPSIZ
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and asrc = -8, src // asrc = src & -OPSIZ -- align src
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shr.u loopcnt = len, 3 // loopcnt = len / 8
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and len = 7, len ;; // len = len % 8
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shl sh1 = sh1, 3 // sh1 = 8 * (src % 8)
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adds loopcnt = -1, loopcnt // --loopcnt
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mov pr.rot = 1 << 16 ;; // set rotating predicates
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sub sh2 = 64, sh1 // sh2 = 64 - sh1
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mov ar.lc = loopcnt // set LC
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cmp.eq p6, p0 = sh1, r0 // is the src aligned?
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(p6) br.cond.sptk .src_aligned ;;
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add src = src, tmp // src += len & -OPSIZ
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mov ar.ec = MEMLAT + 6 + 1 // six more passes needed
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ld8 r[1] = [asrc], 8 // r[1] = w0
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cmp.ne p6, p0 = r0, r0 ;; // clear p6
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.align 32
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.l2:
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(p[0]) ld8 r[0] = [asrc], 8 // r[0] = w1
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(p[MEMLAT]) shr.u tmp1[0] = r[1 + MEMLAT], sh1 // tmp1 = w0 >> sh1
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(p[MEMLAT]) shl tmp2[0] = r[0 + MEMLAT], sh2 // tmp2 = w1 << sh2
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(p[MEMLAT+4]) xor tmp3[0] = val[1], charx8
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(p[MEMLAT+5]) czx1.r pos0[0] = tmp3[1]
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(p[MEMLAT+6]) cmp.ne p6, p0 = 8, pos0[1]
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(p6) br.cond.spnt .gotit
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(p[MEMLAT+6]) st8 [dest] = val[3], 8 // store val to dest
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(p[MEMLAT+3]) or val[0] = tmp1[3], tmp2[3] // val = tmp1 | tmp2
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br.ctop.sptk .l2
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br.cond.sptk .cpyfew
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.src_aligned:
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cmp.ne p6, p0 = r0, r0 // clear p6
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mov ar.ec = MEMLAT + 2 + 1 ;; // set EC
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.l3:
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(p[0]) ld8 r[0] = [src], 8
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(p[MEMLAT]) xor tmp3[0] = r[MEMLAT], charx8
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(p[MEMLAT+1]) czx1.r pos0[0] = tmp3[1]
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(p[MEMLAT+2]) cmp.ne p7, p0 = 8, pos0[1]
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(p7) br.cond.spnt .gotit
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(p[MEMLAT+2]) st8 [dest] = r[MEMLAT+2], 8
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br.ctop.dptk .l3
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.cpyfew:
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cmp.eq p6, p0 = len, r0 // is len == 0 ?
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adds len = -1, len // --len;
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(p6) br.cond.spnt .restore_and_exit ;;
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mov ar.lc = len
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.l4:
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ld1 value = [src], 1
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;;
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st1 [dest] = value, 1
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cmp.eq p6, p0 = value, char
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(p6) br.cond.spnt .foundit
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br.cloop.dptk .l4 ;;
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.foundit:
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(p6) mov ret0 = dest
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.restore_and_exit:
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mov pr = saved_pr, -1 // restore the predicate registers
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mov ar.lc = saved_lc // restore the loop counter
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br.ret.sptk.many b0
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.gotit:
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.pred.rel "mutex" p6, p7
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(p6) mov value = val[3] // if coming from l2
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(p7) mov value = r[MEMLAT+2] // if coming from l3
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mov ar.lc = pos0[1] ;;
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.l5:
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extr.u tmp = value, 0, 8 ;;
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st1 [dest] = tmp, 1
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shr.u value = value, 8
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br.cloop.sptk .l5 ;;
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mov ret0 = dest
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mov pr = saved_pr, -1
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mov ar.lc = saved_lc
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br.ret.sptk.many b0
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END(memccpy)
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