arch/riscv/include/asm/word-at-a-time.h

   1 /*
   2  * Copyright (C) 2012 Regents of the University of California
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful,
   9  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  *   GNU General Public License for more details.
  12  * Derived from arch/x86/include/asm/word-at-a-time.h
  13  */
  14
  15 #ifndef _ASM_RISCV_WORD_AT_A_TIME_H
  16 #define _ASM_RISCV_WORD_AT_A_TIME_H
  17
  18
  19 #include <linux/kernel.h>
  20
  21 struct word_at_a_time {
  22         const unsigned long one_bits, high_bits;
  23 };
  24
  25 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
  26
  27 static inline unsigned long has_zero(unsigned long val,
  28         unsigned long *bits, const struct word_at_a_time *c)
  29 {
  30         unsigned long mask = ((val - c->one_bits) & ~val) & c->high_bits;
  31         *bits = mask;
  32         return mask;
  33 }
  34
  35 static inline unsigned long prep_zero_mask(unsigned long val,
  36         unsigned long bits, const struct word_at_a_time *c)
  37 {
  38         return bits;
  39 }
  40
  41 static inline unsigned long create_zero_mask(unsigned long bits)
  42 {
  43         bits = (bits - 1) & ~bits;
  44         return bits >> 7;
  45 }
  46
  47 static inline unsigned long find_zero(unsigned long mask)
  48 {
  49         return fls64(mask) >> 3;
  50 }
  51
  52 /* The mask we created is directly usable as a bytemask */
  53 #define zero_bytemask(mask) (mask)
  54
  55 #endif /* _ASM_RISCV_WORD_AT_A_TIME_H */