sysdeps/hppa/string-fzb.h

   1 /* Zero byte detection, boolean.  HPPA version.
   2    Copyright (C) 2023 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _STRING_FZB_H
  20 #define _STRING_FZB_H 1
  21
  22 #include <sys/cdefs.h>
  23 #include <string-optype.h>
  24
  25 _Static_assert (sizeof (op_t) == 4, "64-bit not supported");
  26
  27 /* Determine if any byte within X is zero.  This is a pure boolean test.  */
  28 static __always_inline _Bool
  29 has_zero (op_t x)
  30 {
  31   /* It's more useful to expose a control transfer to the compiler
  32      than to expose a proper boolean result.  */
  33   asm goto ("uxor,sbz %%r0,%0,%%r0\n\t"
  34             "b,n %l1" : : "r"(x) : : nbz);
  35   return 1;
  36  nbz:
  37   return 0;
  38 }
  39
  40 /* Likewise, but for byte equality between X1 and X2.  */
  41 static __always_inline _Bool
  42 has_eq (op_t x1, op_t x2)
  43 {
  44   asm goto ("uxor,sbz %0,%1,%%r0\n\t"
  45             "b,n %l2" : : "r"(x1), "r"(x2) : : nbz);
  46   return 1;
  47  nbz:
  48   return 0;
  49 }
  50
  51 /* Likewise, but for zeros in X1 and equal bytes between X1 and X2.  */
  52 static __always_inline _Bool
  53 has_zero_eq (op_t x1, op_t x2)
  54 {
  55   asm goto ("uxor,sbz %%r0,%0,%%r0\n\t"
  56             "uxor,nbz %0,%1,%%r0\n\t"
  57             "b,n %l2" : : "r"(x1), "r"(x2) : : sbz);
  58   return 0;
  59  sbz:
  60   return 1;
  61 }
  62
  63 #endif /* _STRING_FZB_H */