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
13struct 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 */
20static 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
28static 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
36static 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
43static 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 */
53struct 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 */
59static 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
70static 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 */
76static 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		: "b" (bits));
86
87	return leading_zero_bits;
88}
89
90static 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 */
96static inline unsigned long zero_bytemask(unsigned long mask)
97{
98	return (1UL << mask) - 1;
99}
100
101#else	/* 32-bit case */
102
103struct 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 */
118static 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
126static inline unsigned long create_zero_mask(unsigned long bits)
127{
128	bits = (bits - 1) & ~bits;
129	return bits >> 7;
130}
131
132static 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 */
138static 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
145static 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
166static 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