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 */ 204