root/arch/alpha/include/asm/word-at-a-time.h

INCLUDED FROM

DEFINITIONS

1. has_zero
2. prep_zero_mask
3. find_zero

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_WORD_AT_A_TIME_H
   3 #define _ASM_WORD_AT_A_TIME_H
   4 
   5 #include <asm/compiler.h>
   6 
   7 /*
   8  * word-at-a-time interface for Alpha.
   9  */
  10 
  11 /*
  12  * We do not use the word_at_a_time struct on Alpha, but it needs to be
  13  * implemented to humour the generic code.
  14  */
  15 struct word_at_a_time {
  16         const unsigned long unused;
  17 };
  18 
  19 #define WORD_AT_A_TIME_CONSTANTS { 0 }
  20 
  21 /* Return nonzero if val has a zero */
  22 static inline unsigned long has_zero(unsigned long val, unsigned long *bits, const struct word_at_a_time *c)
  23 {
  24         unsigned long zero_locations = __kernel_cmpbge(0, val);
  25         *bits = zero_locations;
  26         return zero_locations;
  27 }
  28 
  29 static inline unsigned long prep_zero_mask(unsigned long val, unsigned long bits, const struct word_at_a_time *c)
  30 {
  31         return bits;
  32 }
  33 
  34 #define create_zero_mask(bits) (bits)
  35 
  36 static inline unsigned long find_zero(unsigned long bits)
  37 {
  38 #if defined(CONFIG_ALPHA_EV6) && defined(CONFIG_ALPHA_EV67)
  39         /* Simple if have CIX instructions */
  40         return __kernel_cttz(bits);
  41 #else
  42         unsigned long t1, t2, t3;
  43         /* Retain lowest set bit only */
  44         bits &= -bits;
  45         /* Binary search for lowest set bit */
  46         t1 = bits & 0xf0;
  47         t2 = bits & 0xcc;
  48         t3 = bits & 0xaa;
  49         if (t1) t1 = 4;
  50         if (t2) t2 = 2;
  51         if (t3) t3 = 1;
  52         return t1 + t2 + t3;
  53 #endif
  54 }
  55 
  56 #define zero_bytemask(mask) ((2ul << (find_zero(mask) * 8)) - 1)
  57 
  58 #endif /* _ASM_WORD_AT_A_TIME_H */