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 static inline unsigned long zero_bytemask(unsigned long mask)
  44 {
  45         return ~1ul << __fls(mask);
  46 }
  47
  48 #else
  49
  50 #ifdef CONFIG_64BIT
  51
  52 /* unused */
  53 struct word_at_a_time {
  54 };
  55
  56 #define WORD_AT_A_TIME_CONSTANTS { }
  57
  58 /* This will give us 0xff for a NULL char and 0x00 elsewhere */
  59 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
  60 {
  61         unsigned long ret;
  62         unsigned long zero = 0;
  63
  64         asm("cmpb %0,%1,%2" : "=r" (ret) : "r" (a), "r" (zero));
  65         *bits = ret;
  66
  67         return ret;
  68 }
  69
  70 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
  71 {
  72         return bits;
  73 }
  74
  75 /* Alan Modra's little-endian strlen tail for 64-bit */
  76 static inline unsigned long create_zero_mask(unsigned long bits)
  77 {
  78         unsigned long leading_zero_bits;
  79         long trailing_zero_bit_mask;
  80
  81         asm("addi       %1,%2,-1\n\t"
  82             "andc       %1,%1,%2\n\t"
  83             "popcntd    %0,%1"
  84                 : "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask)
  85                 : "r" (bits));
  86
  87         return leading_zero_bits;
  88 }
  89
  90 static inline unsigned long find_zero(unsigned long mask)
  91 {
  92         return mask >> 3;
  93 }
  94
  95 /* This assumes that we never ask for an all 1s bitmask */
  96 static inline unsigned long zero_bytemask(unsigned long mask)
  97 {
  98         return (1UL << mask) - 1;
  99 }
 100
 101 #else   /* 32-bit case */
 102
 103 struct word_at_a_time {
 104         const unsigned long one_bits, high_bits;
 105 };
 106
 107 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
 108
 109 /*
 110  * This is largely generic for little-endian machines, but the
 111  * optimal byte mask counting is probably going to be something
 112  * that is architecture-specific. If you have a reliably fast
 113  * bit count instruction, that might be better than the multiply
 114  * and shift, for example.
 115  */
 116
 117 /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
 118 static inline long count_masked_bytes(long mask)
 119 {
 120         /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
 121         long a = (0x0ff0001+mask) >> 23;
 122         /* Fix the 1 for 00 case */
 123         return a & mask;
 124 }
 125
 126 static inline unsigned long create_zero_mask(unsigned long bits)
 127 {
 128         bits = (bits - 1) & ~bits;
 129         return bits >> 7;
 130 }
 131
 132 static inline unsigned long find_zero(unsigned long mask)
 133 {
 134         return count_masked_bytes(mask);
 135 }
 136
 137 /* Return nonzero if it has a zero */
 138 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
 139 {
 140         unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
 141         *bits = mask;
 142         return mask;
 143 }
 144
 145 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
 146 {
 147         return bits;
 148 }
 149
 150 /* The mask we created is directly usable as a bytemask */
 151 #define zero_bytemask(mask) (mask)
 152
 153 #endif /* CONFIG_64BIT */
 154
 155 #endif /* __BIG_ENDIAN__ */
 156
 157 /*
 158  * We use load_unaligned_zero() in a selftest, which builds a userspace
 159  * program. Some linker scripts seem to discard the .fixup section, so allow
 160  * the test code to use a different section name.
 161  */
 162 #ifndef FIXUP_SECTION
 163 #define FIXUP_SECTION ".fixup"
 164 #endif
 165
 166 static inline unsigned long load_unaligned_zeropad(const void *addr)
 167 {
 168         unsigned long ret, offset, tmp;
 169
 170         asm(
 171         "1:     " PPC_LL "%[ret], 0(%[addr])\n"
 172         "2:\n"
 173         ".section " FIXUP_SECTION ",\"ax\"\n"
 174         "3:     "
 175 #ifdef __powerpc64__
 176         "clrrdi         %[tmp], %[addr], 3\n\t"
 177         "clrlsldi       %[offset], %[addr], 61, 3\n\t"
 178         "ld             %[ret], 0(%[tmp])\n\t"
 179 #ifdef __BIG_ENDIAN__
 180         "sld            %[ret], %[ret], %[offset]\n\t"
 181 #else
 182         "srd            %[ret], %[ret], %[offset]\n\t"
 183 #endif
 184 #else
 185         "clrrwi         %[tmp], %[addr], 2\n\t"
 186         "clrlslwi       %[offset], %[addr], 30, 3\n\t"
 187         "lwz            %[ret], 0(%[tmp])\n\t"
 188 #ifdef __BIG_ENDIAN__
 189         "slw            %[ret], %[ret], %[offset]\n\t"
 190 #else
 191         "srw            %[ret], %[ret], %[offset]\n\t"
 192 #endif
 193 #endif
 194         "b      2b\n"
 195         ".previous\n"
 196         ".section __ex_table,\"a\"\n\t"
 197                 PPC_LONG_ALIGN "\n\t"
 198                 PPC_LONG "1b,3b\n"
 199         ".previous"
 200         : [tmp] "=&b" (tmp), [offset] "=&r" (offset), [ret] "=&r" (ret)
 201         : [addr] "b" (addr), "m" (*(unsigned long *)addr));
 202
 203         return ret;
 204 }
 205
 206 #undef FIXUP_SECTION
 207
 208 #endif /* _ASM_WORD_AT_A_TIME_H */