1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _ASM_WORD_AT_A_TIME_H 3#define _ASM_WORD_AT_A_TIME_H 4 5#include <linux/bitops.h> 6#include <linux/wordpart.h> 7#include <asm/byteorder.h> 8 9#ifdef __BIG_ENDIAN 10 11struct word_at_a_time { 12 const unsigned long high_bits, low_bits; 13}; 14 15#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) } 16 17/* Bit set in the bytes that have a zero */ 18static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c) 19{ 20 unsigned long mask = (val & c->low_bits) + c->low_bits; 21 return ~(mask | rhs); 22} 23 24#define create_zero_mask(mask) (mask) 25 26static inline long find_zero(unsigned long mask) 27{ 28 long byte = 0; 29#ifdef CONFIG_64BIT 30 if (mask >> 32) 31 mask >>= 32; 32 else 33 byte = 4; 34#endif 35 if (mask >> 16) 36 mask >>= 16; 37 else 38 byte += 2; 39 return (mask >> 8) ? byte : byte + 1; 40} 41 42static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c) 43{ 44 unsigned long rhs = val | c->low_bits; 45 *data = rhs; 46 return (val + c->high_bits) & ~rhs; 47} 48 49#ifndef zero_bytemask 50#define zero_bytemask(mask) (~1ul << __fls(mask)) 51#endif 52 53#else 54 55/* 56 * The optimal byte mask counting is probably going to be something 57 * that is architecture-specific. If you have a reliably fast 58 * bit count instruction, that might be better than the multiply 59 * and shift, for example. 60 */ 61struct word_at_a_time { 62 const unsigned long one_bits, high_bits; 63}; 64 65#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } 66 67#ifdef CONFIG_64BIT 68 69/* 70 * Jan Achrenius on G+: microoptimized version of 71 * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56" 72 * that works for the bytemasks without having to 73 * mask them first. 74 */ 75static inline long count_masked_bytes(unsigned long mask) 76{ 77 return mask*0x0001020304050608ul >> 56; 78} 79 80#else /* 32-bit case */ 81 82/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */ 83static inline long count_masked_bytes(long mask) 84{ 85 /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */ 86 long a = (0x0ff0001+mask) >> 23; 87 /* Fix the 1 for 00 case */ 88 return a & mask; 89} 90 91#endif 92 93/* Return nonzero if it has a zero */ 94static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c) 95{ 96 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; 97 *bits = mask; 98 return mask; 99} 100 101static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c) 102{ 103 return bits; 104} 105 106static inline unsigned long create_zero_mask(unsigned long bits) 107{ 108 bits = (bits - 1) & ~bits; 109 return bits >> 7; 110} 111 112/* The mask we created is directly usable as a bytemask */ 113#define zero_bytemask(mask) (mask) 114 115static inline unsigned long find_zero(unsigned long mask) 116{ 117 return count_masked_bytes(mask); 118} 119 120#endif /* __BIG_ENDIAN */ 121 122#endif /* _ASM_WORD_AT_A_TIME_H */ 123