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/kernel.h>
  6#include <asm/byteorder.h>
 
 
 
 
 
  7
  8#ifdef __BIG_ENDIAN
  9
 10struct word_at_a_time {
 11	const unsigned long high_bits, low_bits;
 12};
 13
 14#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
 15
 16/* Bit set in the bytes that have a zero */
 17static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
 18{
 19	unsigned long mask = (val & c->low_bits) + c->low_bits;
 20	return ~(mask | rhs);
 21}
 22
 23#define create_zero_mask(mask) (mask)
 24
 25static inline long find_zero(unsigned long mask)
 26{
 27	long byte = 0;
 28#ifdef CONFIG_64BIT
 29	if (mask >> 32)
 30		mask >>= 32;
 31	else
 32		byte = 4;
 33#endif
 34	if (mask >> 16)
 35		mask >>= 16;
 36	else
 37		byte += 2;
 38	return (mask >> 8) ? byte : byte + 1;
 39}
 40
 41static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
 42{
 43	unsigned long rhs = val | c->low_bits;
 44	*data = rhs;
 45	return (val + c->high_bits) & ~rhs;
 46}
 47
 48#ifndef zero_bytemask
 49#define zero_bytemask(mask) (~1ul << __fls(mask))
 50#endif
 51
 52#else
 53
 54/*
 55 * The optimal byte mask counting is probably going to be something
 56 * that is architecture-specific. If you have a reliably fast
 57 * bit count instruction, that might be better than the multiply
 58 * and shift, for example.
 59 */
 60struct word_at_a_time {
 61	const unsigned long one_bits, high_bits;
 62};
 63
 64#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
 65
 66#ifdef CONFIG_64BIT
 67
 68/*
 69 * Jan Achrenius on G+: microoptimized version of
 70 * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56"
 71 * that works for the bytemasks without having to
 72 * mask them first.
 73 */
 74static inline long count_masked_bytes(unsigned long mask)
 75{
 76	return mask*0x0001020304050608ul >> 56;
 77}
 78
 79#else	/* 32-bit case */
 80
 81/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
 82static inline long count_masked_bytes(long mask)
 83{
 84	/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
 85	long a = (0x0ff0001+mask) >> 23;
 86	/* Fix the 1 for 00 case */
 87	return a & mask;
 88}
 89
 90#endif
 91
 92/* Return nonzero if it has a zero */
 93static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
 94{
 95	unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
 96	*bits = mask;
 97	return mask;
 98}
 99
100static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
101{
102	return bits;
103}
104
105static inline unsigned long create_zero_mask(unsigned long bits)
106{
107	bits = (bits - 1) & ~bits;
108	return bits >> 7;
109}
110
111/* The mask we created is directly usable as a bytemask */
112#define zero_bytemask(mask) (mask)
113
114static inline unsigned long find_zero(unsigned long mask)
115{
116	return count_masked_bytes(mask);
117}
118
119#endif /* __BIG_ENDIAN */
120
121#endif /* _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 * This says "generic", but it's actually big-endian only.
 6 * Little-endian can use more efficient versions of these
 7 * interfaces, see for example
 8 *	 arch/x86/include/asm/word-at-a-time.h
 9 * for those.
10 */
11
12#include <linux/kernel.h>
13
14struct 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 */
21static 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
29static inline long find_zero(unsigned long mask)
30{
31	long byte = 0;
32#ifdef CONFIG_64BIT
33	if (mask >> 32)
34		mask >>= 32;
35	else
36		byte = 4;
37#endif
38	if (mask >> 16)
39		mask >>= 16;
40	else
41		byte += 2;
42	return (mask >> 8) ? byte : byte + 1;
43}
44
45static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
46{
47	unsigned long rhs = val | c->low_bits;
48	*data = rhs;
49	return (val + c->high_bits) & ~rhs;
50}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
51
52#endif /* _ASM_WORD_AT_A_TIME_H */