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
43#else
44
45#ifdef CONFIG_64BIT
46
47/* unused */
48struct 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 */
54static 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
65static 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 */
71static 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		: "b" (bits));
81
82	return leading_zero_bits;
83}
84
85static 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 */
91static inline unsigned long zero_bytemask(unsigned long mask)
92{
93	return (1UL << mask) - 1;
94}
95
96#else	/* 32-bit case */
97
98struct 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 */
113static 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
121static inline unsigned long create_zero_mask(unsigned long bits)
122{
123	bits = (bits - 1) & ~bits;
124	return bits >> 7;
125}
126
127static 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 */
133static 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
140static 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
161static 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