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 #include <asm/ppc_asm.h>
11 
12 #ifdef __BIG_ENDIAN__
13 
14 struct 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 */
21 static 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 
29 static inline long find_zero(unsigned long mask)
30 {
31 	long leading_zero_bits;
32 
33 	asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask));
34 	return leading_zero_bits >> 3;
35 }
36 
37 static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
38 {
39 	unsigned long rhs = val | c->low_bits;
40 	*data = rhs;
41 	return (val + c->high_bits) & ~rhs;
42 }
43 
44 static inline unsigned long zero_bytemask(unsigned long mask)
45 {
46 	return ~1ul << __fls(mask);
47 }
48 
49 #else
50 
51 #ifdef CONFIG_64BIT
52 
53 /* unused */
54 struct word_at_a_time {
55 };
56 
57 #define WORD_AT_A_TIME_CONSTANTS { }
58 
59 /* This will give us 0xff for a NULL char and 0x00 elsewhere */
60 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
61 {
62 	unsigned long ret;
63 	unsigned long zero = 0;
64 
65 	asm("cmpb %0,%1,%2" : "=r" (ret) : "r" (a), "r" (zero));
66 	*bits = ret;
67 
68 	return ret;
69 }
70 
71 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
72 {
73 	return bits;
74 }
75 
76 /* Alan Modra's little-endian strlen tail for 64-bit */
77 static inline unsigned long create_zero_mask(unsigned long bits)
78 {
79 	unsigned long leading_zero_bits;
80 	long trailing_zero_bit_mask;
81 
82 	asm("addi	%1,%2,-1\n\t"
83 	    "andc	%1,%1,%2\n\t"
84 	    "popcntd	%0,%1"
85 		: "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask)
86 		: "b" (bits));
87 
88 	return leading_zero_bits;
89 }
90 
91 static inline unsigned long find_zero(unsigned long mask)
92 {
93 	return mask >> 3;
94 }
95 
96 /* This assumes that we never ask for an all 1s bitmask */
97 static inline unsigned long zero_bytemask(unsigned long mask)
98 {
99 	return (1UL << mask) - 1;
100 }
101 
102 #else	/* 32-bit case */
103 
104 struct word_at_a_time {
105 	const unsigned long one_bits, high_bits;
106 };
107 
108 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
109 
110 /*
111  * This is largely generic for little-endian machines, but the
112  * optimal byte mask counting is probably going to be something
113  * that is architecture-specific. If you have a reliably fast
114  * bit count instruction, that might be better than the multiply
115  * and shift, for example.
116  */
117 
118 /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
119 static inline long count_masked_bytes(long mask)
120 {
121 	/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
122 	long a = (0x0ff0001+mask) >> 23;
123 	/* Fix the 1 for 00 case */
124 	return a & mask;
125 }
126 
127 static inline unsigned long create_zero_mask(unsigned long bits)
128 {
129 	bits = (bits - 1) & ~bits;
130 	return bits >> 7;
131 }
132 
133 static inline unsigned long find_zero(unsigned long mask)
134 {
135 	return count_masked_bytes(mask);
136 }
137 
138 /* Return nonzero if it has a zero */
139 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
140 {
141 	unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
142 	*bits = mask;
143 	return mask;
144 }
145 
146 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
147 {
148 	return bits;
149 }
150 
151 /* The mask we created is directly usable as a bytemask */
152 #define zero_bytemask(mask) (mask)
153 
154 #endif /* CONFIG_64BIT */
155 
156 #endif /* __BIG_ENDIAN__ */
157 
158 /*
159  * We use load_unaligned_zero() in a selftest, which builds a userspace
160  * program. Some linker scripts seem to discard the .fixup section, so allow
161  * the test code to use a different section name.
162  */
163 #ifndef FIXUP_SECTION
164 #define FIXUP_SECTION ".fixup"
165 #endif
166 
167 static inline unsigned long load_unaligned_zeropad(const void *addr)
168 {
169 	unsigned long ret, offset, tmp;
170 
171 	asm(
172 	"1:	" PPC_LL "%[ret], 0(%[addr])\n"
173 	"2:\n"
174 	".section " FIXUP_SECTION ",\"ax\"\n"
175 	"3:	"
176 #ifdef __powerpc64__
177 	"clrrdi		%[tmp], %[addr], 3\n\t"
178 	"clrlsldi	%[offset], %[addr], 61, 3\n\t"
179 	"ld		%[ret], 0(%[tmp])\n\t"
180 #ifdef __BIG_ENDIAN__
181 	"sld		%[ret], %[ret], %[offset]\n\t"
182 #else
183 	"srd		%[ret], %[ret], %[offset]\n\t"
184 #endif
185 #else
186 	"clrrwi		%[tmp], %[addr], 2\n\t"
187 	"clrlslwi	%[offset], %[addr], 30, 3\n\t"
188 	"lwz		%[ret], 0(%[tmp])\n\t"
189 #ifdef __BIG_ENDIAN__
190 	"slw		%[ret], %[ret], %[offset]\n\t"
191 #else
192 	"srw		%[ret], %[ret], %[offset]\n\t"
193 #endif
194 #endif
195 	"b	2b\n"
196 	".previous\n"
197 	EX_TABLE(1b, 3b)
198 	: [tmp] "=&b" (tmp), [offset] "=&r" (offset), [ret] "=&r" (ret)
199 	: [addr] "b" (addr), "m" (*(unsigned long *)addr));
200 
201 	return ret;
202 }
203 
204 #undef FIXUP_SECTION
205 
206 #endif /* _ASM_WORD_AT_A_TIME_H */
207