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

   1 #ifndef _ASM_WORD_AT_A_TIME_H
   2 #define _ASM_WORD_AT_A_TIME_H
   3
   4 /*
   5  * Word-at-a-time interfaces for PowerPC.
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <asm/asm-compat.h>
  10
  11 #ifdef __BIG_ENDIAN__
  12
  13 struct word_at_a_time {
  14         const unsigned long high_bits, low_bits;
  15 };
  16
  17 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
  18
  19 /* Bit set in the bytes that have a zero */
  20 static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
  21 {
  22         unsigned long mask = (val & c->low_bits) + c->low_bits;
  23         return ~(mask | rhs);
  24 }
  25
  26 #define create_zero_mask(mask) (mask)
  27
  28 static inline long find_zero(unsigned long mask)
  29 {
  30         long leading_zero_bits;
  31
  32         asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask));
  33         return leading_zero_bits >> 3;
  34 }
  35
  36 static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
  37 {
  38         unsigned long rhs = val | c->low_bits;
  39         *data = rhs;
  40         return (val + c->high_bits) & ~rhs;
  41 }
  42
  43 #else
  44
  45 struct word_at_a_time {
  46         const unsigned long one_bits, high_bits;
  47 };
  48
  49 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
  50
  51 #ifdef CONFIG_64BIT
  52
  53 /* Alan Modra's little-endian strlen tail for 64-bit */
  54 #define create_zero_mask(mask) (mask)
  55
  56 static inline unsigned long find_zero(unsigned long mask)
  57 {
  58         unsigned long leading_zero_bits;
  59         long trailing_zero_bit_mask;
  60
  61         asm ("addi %1,%2,-1\n\t"
  62              "andc %1,%1,%2\n\t"
  63              "popcntd %0,%1"
  64              : "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask)
  65              : "r" (mask));
  66         return leading_zero_bits >> 3;
  67 }
  68
  69 #else   /* 32-bit case */
  70
  71 /*
  72  * This is largely generic for little-endian machines, but the
  73  * optimal byte mask counting is probably going to be something
  74  * that is architecture-specific. If you have a reliably fast
  75  * bit count instruction, that might be better than the multiply
  76  * and shift, for example.
  77  */
  78
  79 /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
  80 static inline long count_masked_bytes(long mask)
  81 {
  82         /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
  83         long a = (0x0ff0001+mask) >> 23;
  84         /* Fix the 1 for 00 case */
  85         return a & mask;
  86 }
  87
  88 static inline unsigned long create_zero_mask(unsigned long bits)
  89 {
  90         bits = (bits - 1) & ~bits;
  91         return bits >> 7;
  92 }
  93
  94 static inline unsigned long find_zero(unsigned long mask)
  95 {
  96         return count_masked_bytes(mask);
  97 }
  98
  99 #endif
 100
 101 /* Return nonzero if it has a zero */
 102 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
 103 {
 104         unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
 105         *bits = mask;
 106         return mask;
 107 }
 108
 109 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
 110 {
 111         return bits;
 112 }
 113
 114 /* The mask we created is directly usable as a bytemask */
 115 #define zero_bytemask(mask) (mask)
 116
 117 #endif
 118
 119 #endif /* _ASM_WORD_AT_A_TIME_H */