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 */ 209