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kernel/linux-rt-4.4.41/arch/alpha/include/asm/word-at-a-time.h 1.31 KB
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  #ifndef _ASM_WORD_AT_A_TIME_H
  #define _ASM_WORD_AT_A_TIME_H
  
  #include <asm/compiler.h>
  
  /*
   * word-at-a-time interface for Alpha.
   */
  
  /*
   * We do not use the word_at_a_time struct on Alpha, but it needs to be
   * implemented to humour the generic code.
   */
  struct word_at_a_time {
  	const unsigned long unused;
  };
  
  #define WORD_AT_A_TIME_CONSTANTS { 0 }
  
  /* Return nonzero if val has a zero */
  static inline unsigned long has_zero(unsigned long val, unsigned long *bits, const struct word_at_a_time *c)
  {
  	unsigned long zero_locations = __kernel_cmpbge(0, val);
  	*bits = zero_locations;
  	return zero_locations;
  }
  
  static inline unsigned long prep_zero_mask(unsigned long val, unsigned long bits, const struct word_at_a_time *c)
  {
  	return bits;
  }
  
  #define create_zero_mask(bits) (bits)
  
  static inline unsigned long find_zero(unsigned long bits)
  {
  #if defined(CONFIG_ALPHA_EV6) && defined(CONFIG_ALPHA_EV67)
  	/* Simple if have CIX instructions */
  	return __kernel_cttz(bits);
  #else
  	unsigned long t1, t2, t3;
  	/* Retain lowest set bit only */
  	bits &= -bits;
  	/* Binary search for lowest set bit */
  	t1 = bits & 0xf0;
  	t2 = bits & 0xcc;
  	t3 = bits & 0xaa;
  	if (t1) t1 = 4;
  	if (t2) t2 = 2;
  	if (t3) t3 = 1;
  	return t1 + t2 + t3;
  #endif
  }
  
  #define zero_bytemask(mask) ((2ul << (find_zero(mask) * 8)) - 1)
  
  #endif /* _ASM_WORD_AT_A_TIME_H */