sysdeps/alpha/string-fza.h

   1 /* Basic zero byte detection.  Generic C version.
   2    Copyright (C) 2023-2024 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_FZA_H
  20 #define _STRING_FZA_H 1
  21
  22 #include <string-misc.h>
  23 #include <string-optype.h>
  24
  25 /* The CMPBGE instruction creates a bit mask rather than a byte mask.
  26    However, if we narrow find_t to either 'int' or 'uint8_t', we get
  27    unnecessary truncation instructions from the 'unsigned long' type
  28    returned by __builtin_alpha_cmpbge.  */
  29 typedef op_t find_t;
  30
  31 static __always_inline find_t
  32 find_zero_all (op_t x)
  33 {
  34   return __builtin_alpha_cmpbge (0, x);
  35 }
  36
  37 static __always_inline find_t
  38 find_eq_all (op_t x1, op_t x2)
  39 {
  40   return find_zero_all (x1 ^ x2);
  41 }
  42
  43 static __always_inline find_t
  44 find_zero_eq_all (op_t x1, op_t x2)
  45 {
  46   return find_zero_all (x1) | find_zero_all (x1 ^ x2);
  47 }
  48
  49 static __always_inline find_t
  50 find_zero_ne_all (op_t x1, op_t x2)
  51 {
  52   return find_zero_all (x1) | (find_zero_all (x1 ^ x2) ^ 0xff);
  53 }
  54
  55 /* Define the "inexact" versions in terms of the exact versions.  */
  56 #define find_zero_low           find_zero_all
  57 #define find_eq_low             find_eq_all
  58 #define find_zero_eq_low        find_zero_eq_all
  59
  60 #endif /* _STRING_FZA_H */