sysdeps/s390/memchr-z900.S

   1 /* Search a character in a block of memory.  31/64 bit S/390 version.
   2    Copyright (C) 2001-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* INPUT PARAMETERS
  20      %r2 = address to memory area
  21      %r3 = character to find
  22      %r4 = number of bytes to search.  */
  23
  24 #include <ifunc-memchr.h>
  25 #include "sysdep.h"
  26 #include "asm-syntax.h"
  27
  28 #if HAVE_MEMCHR_Z900_G5
  29 # if defined __s390x__
  30 #  define SLGR  slgr
  31 #  define LGHI  lghi
  32 #  define NGR   ngr
  33 #  define LGR   lgr
  34 # else
  35 #  define SLGR  slr
  36 #  define LGHI  lhi
  37 #  define NGR   nr
  38 #  define LGR   lr
  39 # endif /* ! defined __s390x__  */
  40
  41         .text
  42 ENTRY(MEMCHR_Z900_G5)
  43         LGHI  %r0,0xff
  44         NGR   %r0,%r3
  45         LGR   %r1,%r2
  46 # if ! defined __s390x__
  47         tmlh  %r4,32768
  48         jo    3f                /* Jump away if n >= 0x80000000  */
  49 # endif
  50         la    %r2,0(%r4,%r1)
  51 0:      srst  %r2,%r1
  52         jo    0b
  53         brc   13,1f
  54         SLGR  %r2,%r2
  55 1:      br    %r14
  56 # if ! defined __s390x__
  57         /* On s390 (31bit), the pointer to the first byte after s (stored in
  58            r2) always wraps around with n >= 0x80000000 and can lead to stop
  59            searching before end of s.  Thus just use r2=0 in this case.
  60            If r2 < r1, the srst instruction stops searching with cc=2 "not
  61            found" when wrapping around from top address to zero.  */
  62 3:      SLGR  %r2,%r2
  63         j     0b
  64 # endif
  65 END(MEMCHR_Z900_G5)
  66
  67 # if ! HAVE_MEMCHR_IFUNC
  68 strong_alias (MEMCHR_Z900_G5, __memchr)
  69 weak_alias (__memchr, memchr)
  70 # endif
  71
  72 # if defined SHARED && IS_IN (libc)
  73 strong_alias (MEMCHR_Z900_G5, __GI_memchr)
  74 # endif
  75 #endif