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1#ifndef _LINUX_MATH64_H
2#define _LINUX_MATH64_H
3
4#include <linux/types.h>
5#include <asm/div64.h>
6
7#if BITS_PER_LONG == 64
8
9#define div64_long(x, y) div64_s64((x), (y))
10#define div64_ul(x, y) div64_u64((x), (y))
11
12/**
13 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
14 *
15 * This is commonly provided by 32bit archs to provide an optimized 64bit
16 * divide.
17 */
18static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
19{
20 *remainder = dividend % divisor;
21 return dividend / divisor;
22}
23
24/**
25 * div_s64_rem - signed 64bit divide with 32bit divisor with remainder
26 */
27static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
28{
29 *remainder = dividend % divisor;
30 return dividend / divisor;
31}
32
33/**
34 * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
35 */
36static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
37{
38 *remainder = dividend % divisor;
39 return dividend / divisor;
40}
41
42/**
43 * div64_u64 - unsigned 64bit divide with 64bit divisor
44 */
45static inline u64 div64_u64(u64 dividend, u64 divisor)
46{
47 return dividend / divisor;
48}
49
50/**
51 * div64_s64 - signed 64bit divide with 64bit divisor
52 */
53static inline s64 div64_s64(s64 dividend, s64 divisor)
54{
55 return dividend / divisor;
56}
57
58#elif BITS_PER_LONG == 32
59
60#define div64_long(x, y) div_s64((x), (y))
61#define div64_ul(x, y) div_u64((x), (y))
62
63#ifndef div_u64_rem
64static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
65{
66 *remainder = do_div(dividend, divisor);
67 return dividend;
68}
69#endif
70
71#ifndef div_s64_rem
72extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
73#endif
74
75#ifndef div64_u64_rem
76extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder);
77#endif
78
79#ifndef div64_u64
80extern u64 div64_u64(u64 dividend, u64 divisor);
81#endif
82
83#ifndef div64_s64
84extern s64 div64_s64(s64 dividend, s64 divisor);
85#endif
86
87#endif /* BITS_PER_LONG */
88
89/**
90 * div_u64 - unsigned 64bit divide with 32bit divisor
91 *
92 * This is the most common 64bit divide and should be used if possible,
93 * as many 32bit archs can optimize this variant better than a full 64bit
94 * divide.
95 */
96#ifndef div_u64
97static inline u64 div_u64(u64 dividend, u32 divisor)
98{
99 u32 remainder;
100 return div_u64_rem(dividend, divisor, &remainder);
101}
102#endif
103
104/**
105 * div_s64 - signed 64bit divide with 32bit divisor
106 */
107#ifndef div_s64
108static inline s64 div_s64(s64 dividend, s32 divisor)
109{
110 s32 remainder;
111 return div_s64_rem(dividend, divisor, &remainder);
112}
113#endif
114
115u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
116
117static __always_inline u32
118__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
119{
120 u32 ret = 0;
121
122 while (dividend >= divisor) {
123 /* The following asm() prevents the compiler from
124 optimising this loop into a modulo operation. */
125 asm("" : "+rm"(dividend));
126
127 dividend -= divisor;
128 ret++;
129 }
130
131 *remainder = dividend;
132
133 return ret;
134}
135
136#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
137
138#ifndef mul_u64_u32_shr
139static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
140{
141 return (u64)(((unsigned __int128)a * mul) >> shift);
142}
143#endif /* mul_u64_u32_shr */
144
145#ifndef mul_u64_u64_shr
146static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
147{
148 return (u64)(((unsigned __int128)a * mul) >> shift);
149}
150#endif /* mul_u64_u64_shr */
151
152#else
153
154#ifndef mul_u64_u32_shr
155static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
156{
157 u32 ah, al;
158 u64 ret;
159
160 al = a;
161 ah = a >> 32;
162
163 ret = ((u64)al * mul) >> shift;
164 if (ah)
165 ret += ((u64)ah * mul) << (32 - shift);
166
167 return ret;
168}
169#endif /* mul_u64_u32_shr */
170
171#ifndef mul_u64_u64_shr
172static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift)
173{
174 union {
175 u64 ll;
176 struct {
177#ifdef __BIG_ENDIAN
178 u32 high, low;
179#else
180 u32 low, high;
181#endif
182 } l;
183 } rl, rm, rn, rh, a0, b0;
184 u64 c;
185
186 a0.ll = a;
187 b0.ll = b;
188
189 rl.ll = (u64)a0.l.low * b0.l.low;
190 rm.ll = (u64)a0.l.low * b0.l.high;
191 rn.ll = (u64)a0.l.high * b0.l.low;
192 rh.ll = (u64)a0.l.high * b0.l.high;
193
194 /*
195 * Each of these lines computes a 64-bit intermediate result into "c",
196 * starting at bits 32-95. The low 32-bits go into the result of the
197 * multiplication, the high 32-bits are carried into the next step.
198 */
199 rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low;
200 rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low;
201 rh.l.high = (c >> 32) + rh.l.high;
202
203 /*
204 * The 128-bit result of the multiplication is in rl.ll and rh.ll,
205 * shift it right and throw away the high part of the result.
206 */
207 if (shift == 0)
208 return rl.ll;
209 if (shift < 64)
210 return (rl.ll >> shift) | (rh.ll << (64 - shift));
211 return rh.ll >> (shift & 63);
212}
213#endif /* mul_u64_u64_shr */
214
215#endif
216
217#ifndef mul_u64_u32_div
218static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
219{
220 union {
221 u64 ll;
222 struct {
223#ifdef __BIG_ENDIAN
224 u32 high, low;
225#else
226 u32 low, high;
227#endif
228 } l;
229 } u, rl, rh;
230
231 u.ll = a;
232 rl.ll = (u64)u.l.low * mul;
233 rh.ll = (u64)u.l.high * mul + rl.l.high;
234
235 /* Bits 32-63 of the result will be in rh.l.low. */
236 rl.l.high = do_div(rh.ll, divisor);
237
238 /* Bits 0-31 of the result will be in rl.l.low. */
239 do_div(rl.ll, divisor);
240
241 rl.l.high = rh.l.low;
242 return rl.ll;
243}
244#endif /* mul_u64_u32_div */
245
246#endif /* _LINUX_MATH64_H */