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 #ifdef CONFIG_64BIT
  46
  47 /* unused */
  48 struct word_at_a_time {
  49 };
  50
  51 #define WORD_AT_A_TIME_CONSTANTS { }
  52
  53 /* This will give us 0xff for a NULL char and 0x00 elsewhere */
  54 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
  55 {
  56         unsigned long ret;
  57         unsigned long zero = 0;
  58
  59         asm("cmpb %0,%1,%2" : "=r" (ret) : "r" (a), "r" (zero));
  60         *bits = ret;
  61
  62         return ret;
  63 }
  64
  65 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
  66 {
  67         return bits;
  68 }
  69
  70 /* Alan Modra's little-endian strlen tail for 64-bit */
  71 static inline unsigned long create_zero_mask(unsigned long bits)
  72 {
  73         unsigned long leading_zero_bits;
  74         long trailing_zero_bit_mask;
  75
  76         asm("addi       %1,%2,-1\n\t"
  77             "andc       %1,%1,%2\n\t"
  78             "popcntd    %0,%1"
  79                 : "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask)
  80                 : "r" (bits));
  81
  82         return leading_zero_bits;
  83 }
  84
  85 static inline unsigned long find_zero(unsigned long mask)
  86 {
  87         return mask >> 3;
  88 }
  89
  90 /* This assumes that we never ask for an all 1s bitmask */
  91 static inline unsigned long zero_bytemask(unsigned long mask)
  92 {
  93         return (1UL << mask) - 1;
  94 }
  95
  96 #else   /* 32-bit case */
  97
  98 struct word_at_a_time {
  99         const unsigned long one_bits, high_bits;
 100 };
 101
 102 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
 103
 104 /*
 105  * This is largely generic for little-endian machines, but the
 106  * optimal byte mask counting is probably going to be something
 107  * that is architecture-specific. If you have a reliably fast
 108  * bit count instruction, that might be better than the multiply
 109  * and shift, for example.
 110  */
 111
 112 /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
 113 static inline long count_masked_bytes(long mask)
 114 {
 115         /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
 116         long a = (0x0ff0001+mask) >> 23;
 117         /* Fix the 1 for 00 case */
 118         return a & mask;
 119 }
 120
 121 static inline unsigned long create_zero_mask(unsigned long bits)
 122 {
 123         bits = (bits - 1) & ~bits;
 124         return bits >> 7;
 125 }
 126
 127 static inline unsigned long find_zero(unsigned long mask)
 128 {
 129         return count_masked_bytes(mask);
 130 }
 131
 132 /* Return nonzero if it has a zero */
 133 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
 134 {
 135         unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
 136         *bits = mask;
 137         return mask;
 138 }
 139
 140 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
 141 {
 142         return bits;
 143 }
 144
 145 /* The mask we created is directly usable as a bytemask */
 146 #define zero_bytemask(mask) (mask)
 147
 148 #endif /* CONFIG_64BIT */
 149
 150 #endif /* __BIG_ENDIAN__ */
 151
 152 /*
 153  * We use load_unaligned_zero() in a selftest, which builds a userspace
 154  * program. Some linker scripts seem to discard the .fixup section, so allow
 155  * the test code to use a different section name.
 156  */
 157 #ifndef FIXUP_SECTION
 158 #define FIXUP_SECTION ".fixup"
 159 #endif
 160
 161 static inline unsigned long load_unaligned_zeropad(const void *addr)
 162 {
 163         unsigned long ret, offset, tmp;
 164
 165         asm(
 166         "1:     " PPC_LL "%[ret], 0(%[addr])\n"
 167         "2:\n"
 168         ".section " FIXUP_SECTION ",\"ax\"\n"
 169         "3:     "
 170 #ifdef __powerpc64__
 171         "clrrdi         %[tmp], %[addr], 3\n\t"
 172         "clrlsldi       %[offset], %[addr], 61, 3\n\t"
 173         "ld             %[ret], 0(%[tmp])\n\t"
 174 #ifdef __BIG_ENDIAN__
 175         "sld            %[ret], %[ret], %[offset]\n\t"
 176 #else
 177         "srd            %[ret], %[ret], %[offset]\n\t"
 178 #endif
 179 #else
 180         "clrrwi         %[tmp], %[addr], 2\n\t"
 181         "clrlslwi       %[offset], %[addr], 30, 3\n\t"
 182         "lwz            %[ret], 0(%[tmp])\n\t"
 183 #ifdef __BIG_ENDIAN__
 184         "slw            %[ret], %[ret], %[offset]\n\t"
 185 #else
 186         "srw            %[ret], %[ret], %[offset]\n\t"
 187 #endif
 188 #endif
 189         "b      2b\n"
 190         ".previous\n"
 191         ".section __ex_table,\"a\"\n\t"
 192                 PPC_LONG_ALIGN "\n\t"
 193                 PPC_LONG "1b,3b\n"
 194         ".previous"
 195         : [tmp] "=&b" (tmp), [offset] "=&r" (offset), [ret] "=&r" (ret)
 196         : [addr] "b" (addr), "m" (*(unsigned long *)addr));
 197
 198         return ret;
 199 }
 200
 201 #undef FIXUP_SECTION
 202
 203 #endif /* _ASM_WORD_AT_A_TIME_H */