sysdeps/ia64/strncpy.S

   1 /* Optimized version of the standard strncpy() function.
   2    This file is part of the GNU C Library.
   3    Copyright (C) 2000-2019 Free Software Foundation, Inc.
   4    Contributed by Dan Pop <Dan.Pop@cern.ch>
   5               and Jakub Jelinek <jakub@redhat.com>.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 /* Return: dest
  22
  23    Inputs:
  24         in0:    dest
  25         in1:    src
  26         in2:    len
  27
  28    In this form, it assumes little endian mode.
  29  */
  30
  31 #include <sysdep.h>
  32 #undef ret
  33
  34 #define saved_lc        r15
  35 #define saved_pr        r16
  36 #define thresh          r17
  37 #define dest            r18
  38 #define dest2           r19
  39 #define src             r20
  40 #define len             r21
  41 #define asrc            r22
  42 #define tmp             r23
  43 #define pos             r24
  44 #define w0              r25
  45 #define w1              r26
  46 #define c               r27
  47 #define sh2             r28
  48 #define sh1             r29
  49 #define loopcnt         r30
  50 #define value           r31
  51
  52 ENTRY(strncpy)
  53         .prologue
  54         alloc   r2 = ar.pfs, 3, 0, 29, 32
  55
  56 #define MEMLAT 2
  57         .rotr   r[MEMLAT + 2]
  58         .rotp   p[MEMLAT + 1]
  59
  60         mov     ret0 = in0              // return value = dest
  61         .save pr, saved_pr
  62         mov     saved_pr = pr           // save the predicate registers
  63         .save ar.lc, saved_lc
  64         mov     saved_lc = ar.lc        // save the loop counter
  65         mov     ar.ec = 0               // ec is not guaranteed to
  66                                         // be zero upon function entry
  67         .body
  68         cmp.geu p6, p5 = 24, in2
  69 (p6)    br.cond.spnt .short_len
  70         sub     tmp = r0, in0 ;;        // tmp = -dest
  71         mov     len = in2               // len
  72         mov     dest = in0              // dest
  73         mov     src = in1               // src
  74         and     tmp = 7, tmp ;;         // loopcnt = -dest % 8
  75         cmp.eq  p6, p7 = tmp, r0
  76         adds    loopcnt = -1, tmp       // --loopcnt
  77 (p6)    br.cond.sptk .dest_aligned ;;
  78         sub     len = len, tmp          // len -= -dest % 8
  79         mov     ar.lc = loopcnt
  80 .l1:                                    // copy -dest % 8 bytes
  81 (p5)    ld1     c = [src], 1            // c = *src++
  82         ;;
  83         st1     [dest] = c, 1           // *dest++ = c
  84         cmp.ne  p5, p7 = c, r0
  85         br.cloop.dptk .l1 ;;
  86 (p7)    br.cond.dpnt    .found0_align
  87
  88 .dest_aligned:                          // p7 should be cleared here
  89         shr.u   c = len, 3              // c = len / 8
  90         and     sh1 = 7, src            // sh1 = src % 8
  91         and     asrc = -8, src ;;       // asrc = src & -OPSIZ  -- align src
  92         adds    c = (MEMLAT-1), c       // c = (len / 8) + MEMLAT - 1
  93         sub     thresh = 8, sh1
  94         mov     pr.rot = 1 << 16        // set rotating predicates
  95         shl     sh1 = sh1, 3 ;;         // sh1 = 8 * (src % 8)
  96         mov     ar.lc = c               // "infinite" loop
  97         sub     sh2 = 64, sh1           // sh2 = 64 - sh1
  98         cmp.eq  p6, p0 = sh1, r0        // is the src aligned?
  99 (p6)    br.cond.sptk .src_aligned
 100         adds    c = -(MEMLAT-1), c ;;   // c = (len / 8)
 101         ld8     r[1] = [asrc],8
 102         mov     ar.lc = c ;;
 103
 104         .align  32
 105 .l2:
 106 (p6)    st8     [dest] = value, 8       // store val to dest
 107         ld8.s   r[0] = [asrc], 8
 108         shr.u   value = r[1], sh1 ;;    // value = w0 >> sh1
 109         czx1.r  pos = value ;;          // do we have an "early" zero
 110         cmp.lt  p7, p0 = pos, thresh    // in w0 >> sh1?
 111         adds    len = -8, len           // len -= 8
 112 (p7)    br.cond.dpnt .nonalign_found0
 113         chk.s   r[0], .recovery2        // it is safe to do that only
 114 .back2:                                 // after the previous test
 115         shl     tmp = r[0], sh2         // tmp = w1 << sh2
 116         ;;
 117         or      value = value, tmp ;;   // value |= tmp
 118         czx1.r  pos = value ;;
 119         cmp.ne  p7, p6 = 8, pos
 120 (p7)    br.cond.dpnt .nonalign_found0
 121         br.ctop.dptk    .l2 ;;
 122         adds    len = 8, len
 123         br.cond.sptk    .not_found0 ;;
 124 .nonalign_found0:
 125         cmp.gtu p6, p0 = -8, len
 126 (p6)    br.cond.dptk .found0
 127         adds    len = 8, len
 128         br.cond.sptk    .not_found0 ;;
 129
 130         .align  32
 131 .src_aligned:
 132 .l3:
 133 (p[0])          ld8.s   r[0] = [src], 8
 134 (p[MEMLAT])     chk.s   r[MEMLAT], .recovery3
 135 .back3:
 136 (p[MEMLAT])     mov     value = r[MEMLAT]
 137 (p[MEMLAT])     czx1.r  pos = r[MEMLAT] ;;
 138 (p[MEMLAT])     cmp.ne  p7, p0 = 8, pos
 139 (p[MEMLAT])     adds    len = -8, len   // len -= 8
 140 (p7)            br.cond.dpnt .found0
 141 (p[MEMLAT])     st8     [dest] = r[MEMLAT], 8
 142                 br.ctop.dptk .l3 ;;
 143
 144         chk.s   r[MEMLAT-1], .recovery4
 145 .back4:
 146         mov     value = r[MEMLAT-1]
 147
 148 .not_found0:
 149         cmp.eq  p5, p6 = len, r0
 150         adds    len = -1, len
 151 (p5)    br.cond.dptk    .restore_and_exit ;;
 152         mov     ar.lc = len
 153 .l4:
 154 (p6)    extr.u  c = value, 0, 8         // c = value & 0xff
 155 (p6)    shr.u   value = value, 8 ;;
 156         st1     [dest] = c, 1
 157         cmp.ne  p6, p0 = c, r0
 158         br.cloop.dptk   .l4
 159         br.cond.sptk    .restore_and_exit
 160
 161 .found0_align:
 162         mov     pos = 0
 163         adds    len = -8, len
 164         mov     value = 0 ;;
 165 .found0:
 166         shl     tmp = pos, 3
 167         shr.u   loopcnt = len, 4        // loopcnt = len / 16
 168         mov     c = -1 ;;
 169         cmp.eq  p6, p0 = loopcnt, r0
 170         adds    loopcnt = -1, loopcnt
 171         shl     c = c, tmp ;;
 172         and     len = 0xf, len
 173         andcm   value = value, c
 174         mov     ar.lc = loopcnt ;;
 175         cmp.le  p7, p0 = 8, len
 176         adds    dest2 = 16, dest
 177         st8     [dest] = value, 8
 178         and     len = 0x7, len
 179 (p6)    br.cond.dpnt    .l6 ;;
 180 .l5:
 181         st8     [dest] = r0, 16
 182         st8     [dest2] = r0, 16
 183         br.cloop.dptk   .l5 ;;
 184 .l6:
 185 (p7)    st8     [dest] = r0, 8
 186         cmp.eq  p5, p0 = len, r0
 187         adds    len = -1, len
 188 (p5)    br.cond.dptk .restore_and_exit ;;
 189         mov     ar.lc = len ;;
 190 .l7:
 191         st1     [dest] = r0, 1
 192         br.cloop.dptk   .l7 ;;
 193 .restore_and_exit:
 194         mov     ar.lc = saved_lc        // restore the loop counter
 195         mov     pr = saved_pr, -1       // restore the predicate registers
 196         br.ret.sptk.many b0
 197
 198 .short_len:
 199         cmp.eq  p5, p0 = in2, r0
 200         adds    loopcnt = -1, in2
 201 (p5)    br.cond.spnt .restore_and_exit ;;
 202         mov     ar.lc = loopcnt         // p6 should be set when we get here
 203 .l8:
 204 (p6)    ld1     c = [in1], 1            // c = *src++
 205         ;;
 206         st1     [in0] = c, 1            // *dest++ = c
 207 (p6)    cmp.ne  p6, p0 = c, r0
 208         br.cloop.dptk .l8
 209         ;;
 210         mov     ar.lc = saved_lc        // restore the loop counter
 211         mov     pr = saved_pr, -1       // restore the predicate registers
 212         br.ret.sptk.many b0
 213 .recovery2:
 214         add     c = 8, len
 215         add     tmp = -8, asrc ;;
 216         cmp.gtu p8, p5 = c, thresh ;;
 217 (p8)    ld8     r[0] = [tmp]
 218 (p5)    mov     r[0] = r0
 219         br.cond.sptk .back2
 220 .recovery3:
 221         add     tmp = -(MEMLAT + 1) * 8, src ;;
 222         ld8     r[MEMLAT] = [tmp]
 223         br.cond.sptk .back3
 224 .recovery4:
 225         cmp.eq  p5, p6 = len, r0
 226         add     tmp = -MEMLAT * 8, src ;;
 227 (p6)    ld8     r[MEMLAT - 1] = [tmp]
 228 (p5)    mov     r[MEMLAT - 1] = r0
 229         br.cond.sptk .back4
 230 END(strncpy)
 231 libc_hidden_builtin_def (strncpy)