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 #include <asm/ppc_asm.h> 11 12 #ifdef __BIG_ENDIAN__ 13 14 struct word_at_a_time { 15 const unsigned long high_bits, low_bits; 16 }; 17 18 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) } 19 20 /* Bit set in the bytes that have a zero */ 21 static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c) 22 { 23 unsigned long mask = (val & c->low_bits) + c->low_bits; 24 return ~(mask | rhs); 25 } 26 27 #define create_zero_mask(mask) (mask) 28 29 static inline long find_zero(unsigned long mask) 30 { 31 long leading_zero_bits; 32 33 asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask)); 34 return leading_zero_bits >> 3; 35 } 36 37 static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c) 38 { 39 unsigned long rhs = val | c->low_bits; 40 *data = rhs; 41 return (val + c->high_bits) & ~rhs; 42 } 43 44 static inline unsigned long zero_bytemask(unsigned long mask) 45 { 46 return ~1ul << __fls(mask); 47 } 48 49 #else 50 51 #ifdef CONFIG_64BIT 52 53 /* unused */ 54 struct word_at_a_time { 55 }; 56 57 #define WORD_AT_A_TIME_CONSTANTS { } 58 59 /* This will give us 0xff for a NULL char and 0x00 elsewhere */ 60 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c) 61 { 62 unsigned long ret; 63 unsigned long zero = 0; 64 65 asm("cmpb %0,%1,%2" : "=r" (ret) : "r" (a), "r" (zero)); 66 *bits = ret; 67 68 return ret; 69 } 70 71 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c) 72 { 73 return bits; 74 } 75 76 /* Alan Modra's little-endian strlen tail for 64-bit */ 77 static inline unsigned long create_zero_mask(unsigned long bits) 78 { 79 unsigned long leading_zero_bits; 80 long trailing_zero_bit_mask; 81 82 asm("addi %1,%2,-1\n\t" 83 "andc %1,%1,%2\n\t" 84 "popcntd %0,%1" 85 : "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask) 86 : "b" (bits)); 87 88 return leading_zero_bits; 89 } 90 91 static inline unsigned long find_zero(unsigned long mask) 92 { 93 return mask >> 3; 94 } 95 96 /* This assumes that we never ask for an all 1s bitmask */ 97 static inline unsigned long zero_bytemask(unsigned long mask) 98 { 99 return (1UL << mask) - 1; 100 } 101 102 #else /* 32-bit case */ 103 104 struct word_at_a_time { 105 const unsigned long one_bits, high_bits; 106 }; 107 108 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } 109 110 /* 111 * This is largely generic for little-endian machines, but the 112 * optimal byte mask counting is probably going to be something 113 * that is architecture-specific. If you have a reliably fast 114 * bit count instruction, that might be better than the multiply 115 * and shift, for example. 116 */ 117 118 /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */ 119 static inline long count_masked_bytes(long mask) 120 { 121 /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */ 122 long a = (0x0ff0001+mask) >> 23; 123 /* Fix the 1 for 00 case */ 124 return a & mask; 125 } 126 127 static inline unsigned long create_zero_mask(unsigned long bits) 128 { 129 bits = (bits - 1) & ~bits; 130 return bits >> 7; 131 } 132 133 static inline unsigned long find_zero(unsigned long mask) 134 { 135 return count_masked_bytes(mask); 136 } 137 138 /* Return nonzero if it has a zero */ 139 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c) 140 { 141 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; 142 *bits = mask; 143 return mask; 144 } 145 146 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c) 147 { 148 return bits; 149 } 150 151 /* The mask we created is directly usable as a bytemask */ 152 #define zero_bytemask(mask) (mask) 153 154 #endif /* CONFIG_64BIT */ 155 156 #endif /* __BIG_ENDIAN__ */ 157 158 /* 159 * We use load_unaligned_zero() in a selftest, which builds a userspace 160 * program. Some linker scripts seem to discard the .fixup section, so allow 161 * the test code to use a different section name. 162 */ 163 #ifndef FIXUP_SECTION 164 #define FIXUP_SECTION ".fixup" 165 #endif 166 167 static inline unsigned long load_unaligned_zeropad(const void *addr) 168 { 169 unsigned long ret, offset, tmp; 170 171 asm( 172 "1: " PPC_LL "%[ret], 0(%[addr])\n" 173 "2:\n" 174 ".section " FIXUP_SECTION ",\"ax\"\n" 175 "3: " 176 #ifdef __powerpc64__ 177 "clrrdi %[tmp], %[addr], 3\n\t" 178 "clrlsldi %[offset], %[addr], 61, 3\n\t" 179 "ld %[ret], 0(%[tmp])\n\t" 180 #ifdef __BIG_ENDIAN__ 181 "sld %[ret], %[ret], %[offset]\n\t" 182 #else 183 "srd %[ret], %[ret], %[offset]\n\t" 184 #endif 185 #else 186 "clrrwi %[tmp], %[addr], 2\n\t" 187 "clrlslwi %[offset], %[addr], 30, 3\n\t" 188 "lwz %[ret], 0(%[tmp])\n\t" 189 #ifdef __BIG_ENDIAN__ 190 "slw %[ret], %[ret], %[offset]\n\t" 191 #else 192 "srw %[ret], %[ret], %[offset]\n\t" 193 #endif 194 #endif 195 "b 2b\n" 196 ".previous\n" 197 EX_TABLE(1b, 3b) 198 : [tmp] "=&b" (tmp), [offset] "=&r" (offset), [ret] "=&r" (ret) 199 : [addr] "b" (addr), "m" (*(unsigned long *)addr)); 200 201 return ret; 202 } 203 204 #undef FIXUP_SECTION 205 206 #endif /* _ASM_WORD_AT_A_TIME_H */ 207