1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MATH64_H
3 #define _LINUX_MATH64_H
4
5 #include <linux/types.h>
6 #include <linux/math.h>
7 #include <vdso/math64.h>
8 #include <asm/div64.h>
9
10 #if BITS_PER_LONG == 64
11
12 #define div64_long(x, y) div64_s64((x), (y))
13 #define div64_ul(x, y) div64_u64((x), (y))
14
15 /**
16 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
17 * @dividend: unsigned 64bit dividend
18 * @divisor: unsigned 32bit divisor
19 * @remainder: pointer to unsigned 32bit remainder
20 *
21 * Return: sets ``*remainder``, then returns dividend / divisor
22 *
23 * This is commonly provided by 32bit archs to provide an optimized 64bit
24 * divide.
25 */
div_u64_rem(u64 dividend,u32 divisor,u32 * remainder)26 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
27 {
28 *remainder = dividend % divisor;
29 return dividend / divisor;
30 }
31
32 /**
33 * div_s64_rem - signed 64bit divide with 32bit divisor with remainder
34 * @dividend: signed 64bit dividend
35 * @divisor: signed 32bit divisor
36 * @remainder: pointer to signed 32bit remainder
37 *
38 * Return: sets ``*remainder``, then returns dividend / divisor
39 */
div_s64_rem(s64 dividend,s32 divisor,s32 * remainder)40 static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
41 {
42 *remainder = dividend % divisor;
43 return dividend / divisor;
44 }
45
46 /**
47 * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
48 * @dividend: unsigned 64bit dividend
49 * @divisor: unsigned 64bit divisor
50 * @remainder: pointer to unsigned 64bit remainder
51 *
52 * Return: sets ``*remainder``, then returns dividend / divisor
53 */
div64_u64_rem(u64 dividend,u64 divisor,u64 * remainder)54 static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
55 {
56 *remainder = dividend % divisor;
57 return dividend / divisor;
58 }
59
60 /**
61 * div64_u64 - unsigned 64bit divide with 64bit divisor
62 * @dividend: unsigned 64bit dividend
63 * @divisor: unsigned 64bit divisor
64 *
65 * Return: dividend / divisor
66 */
div64_u64(u64 dividend,u64 divisor)67 static inline u64 div64_u64(u64 dividend, u64 divisor)
68 {
69 return dividend / divisor;
70 }
71
72 /**
73 * div64_s64 - signed 64bit divide with 64bit divisor
74 * @dividend: signed 64bit dividend
75 * @divisor: signed 64bit divisor
76 *
77 * Return: dividend / divisor
78 */
div64_s64(s64 dividend,s64 divisor)79 static inline s64 div64_s64(s64 dividend, s64 divisor)
80 {
81 return dividend / divisor;
82 }
83
84 #elif BITS_PER_LONG == 32
85
86 #define div64_long(x, y) div_s64((x), (y))
87 #define div64_ul(x, y) div_u64((x), (y))
88
89 #ifndef div_u64_rem
div_u64_rem(u64 dividend,u32 divisor,u32 * remainder)90 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
91 {
92 *remainder = do_div(dividend, divisor);
93 return dividend;
94 }
95 #endif
96
97 #ifndef div_s64_rem
98 extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
99 #endif
100
101 #ifndef div64_u64_rem
102 extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder);
103 #endif
104
105 #ifndef div64_u64
106 extern u64 div64_u64(u64 dividend, u64 divisor);
107 #endif
108
109 #ifndef div64_s64
110 extern s64 div64_s64(s64 dividend, s64 divisor);
111 #endif
112
113 #endif /* BITS_PER_LONG */
114
115 /**
116 * div_u64 - unsigned 64bit divide with 32bit divisor
117 * @dividend: unsigned 64bit dividend
118 * @divisor: unsigned 32bit divisor
119 *
120 * This is the most common 64bit divide and should be used if possible,
121 * as many 32bit archs can optimize this variant better than a full 64bit
122 * divide.
123 *
124 * Return: dividend / divisor
125 */
126 #ifndef div_u64
div_u64(u64 dividend,u32 divisor)127 static inline u64 div_u64(u64 dividend, u32 divisor)
128 {
129 u32 remainder;
130 return div_u64_rem(dividend, divisor, &remainder);
131 }
132 #endif
133
134 /**
135 * div_s64 - signed 64bit divide with 32bit divisor
136 * @dividend: signed 64bit dividend
137 * @divisor: signed 32bit divisor
138 *
139 * Return: dividend / divisor
140 */
141 #ifndef div_s64
div_s64(s64 dividend,s32 divisor)142 static inline s64 div_s64(s64 dividend, s32 divisor)
143 {
144 s32 remainder;
145 return div_s64_rem(dividend, divisor, &remainder);
146 }
147 #endif
148
149 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
150
151 #ifndef mul_u32_u32
152 /*
153 * Many a GCC version messes this up and generates a 64x64 mult :-(
154 */
mul_u32_u32(u32 a,u32 b)155 static inline u64 mul_u32_u32(u32 a, u32 b)
156 {
157 return (u64)a * b;
158 }
159 #endif
160
161 #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
162
163 #ifndef mul_u64_u32_shr
mul_u64_u32_shr(u64 a,u32 mul,unsigned int shift)164 static __always_inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
165 {
166 return (u64)(((unsigned __int128)a * mul) >> shift);
167 }
168 #endif /* mul_u64_u32_shr */
169
170 #ifndef mul_u64_u64_shr
mul_u64_u64_shr(u64 a,u64 mul,unsigned int shift)171 static __always_inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
172 {
173 return (u64)(((unsigned __int128)a * mul) >> shift);
174 }
175 #endif /* mul_u64_u64_shr */
176
177 #else
178
179 #ifndef mul_u64_u32_shr
mul_u64_u32_shr(u64 a,u32 mul,unsigned int shift)180 static __always_inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
181 {
182 u32 ah, al;
183 u64 ret;
184
185 al = a;
186 ah = a >> 32;
187
188 ret = mul_u32_u32(al, mul) >> shift;
189 if (ah)
190 ret += mul_u32_u32(ah, mul) << (32 - shift);
191
192 return ret;
193 }
194 #endif /* mul_u64_u32_shr */
195
196 #ifndef mul_u64_u64_shr
mul_u64_u64_shr(u64 a,u64 b,unsigned int shift)197 static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift)
198 {
199 union {
200 u64 ll;
201 struct {
202 #ifdef __BIG_ENDIAN
203 u32 high, low;
204 #else
205 u32 low, high;
206 #endif
207 } l;
208 } rl, rm, rn, rh, a0, b0;
209 u64 c;
210
211 a0.ll = a;
212 b0.ll = b;
213
214 rl.ll = mul_u32_u32(a0.l.low, b0.l.low);
215 rm.ll = mul_u32_u32(a0.l.low, b0.l.high);
216 rn.ll = mul_u32_u32(a0.l.high, b0.l.low);
217 rh.ll = mul_u32_u32(a0.l.high, b0.l.high);
218
219 /*
220 * Each of these lines computes a 64-bit intermediate result into "c",
221 * starting at bits 32-95. The low 32-bits go into the result of the
222 * multiplication, the high 32-bits are carried into the next step.
223 */
224 rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low;
225 rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low;
226 rh.l.high = (c >> 32) + rh.l.high;
227
228 /*
229 * The 128-bit result of the multiplication is in rl.ll and rh.ll,
230 * shift it right and throw away the high part of the result.
231 */
232 if (shift == 0)
233 return rl.ll;
234 if (shift < 64)
235 return (rl.ll >> shift) | (rh.ll << (64 - shift));
236 return rh.ll >> (shift & 63);
237 }
238 #endif /* mul_u64_u64_shr */
239
240 #endif
241
242 #ifndef mul_s64_u64_shr
mul_s64_u64_shr(s64 a,u64 b,unsigned int shift)243 static inline u64 mul_s64_u64_shr(s64 a, u64 b, unsigned int shift)
244 {
245 u64 ret;
246
247 /*
248 * Extract the sign before the multiplication and put it back
249 * afterwards if needed.
250 */
251 ret = mul_u64_u64_shr(abs(a), b, shift);
252
253 if (a < 0)
254 ret = -((s64) ret);
255
256 return ret;
257 }
258 #endif /* mul_s64_u64_shr */
259
260 #ifndef mul_u64_u32_div
mul_u64_u32_div(u64 a,u32 mul,u32 divisor)261 static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
262 {
263 union {
264 u64 ll;
265 struct {
266 #ifdef __BIG_ENDIAN
267 u32 high, low;
268 #else
269 u32 low, high;
270 #endif
271 } l;
272 } u, rl, rh;
273
274 u.ll = a;
275 rl.ll = mul_u32_u32(u.l.low, mul);
276 rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high;
277
278 /* Bits 32-63 of the result will be in rh.l.low. */
279 rl.l.high = do_div(rh.ll, divisor);
280
281 /* Bits 0-31 of the result will be in rl.l.low. */
282 do_div(rl.ll, divisor);
283
284 rl.l.high = rh.l.low;
285 return rl.ll;
286 }
287 #endif /* mul_u64_u32_div */
288
289 u64 mul_u64_u64_div_u64(u64 a, u64 mul, u64 div);
290
291 /**
292 * DIV64_U64_ROUND_UP - unsigned 64bit divide with 64bit divisor rounded up
293 * @ll: unsigned 64bit dividend
294 * @d: unsigned 64bit divisor
295 *
296 * Divide unsigned 64bit dividend by unsigned 64bit divisor
297 * and round up.
298 *
299 * Return: dividend / divisor rounded up
300 */
301 #define DIV64_U64_ROUND_UP(ll, d) \
302 ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); })
303
304 /**
305 * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer
306 * @dividend: unsigned 64bit dividend
307 * @divisor: unsigned 64bit divisor
308 *
309 * Divide unsigned 64bit dividend by unsigned 64bit divisor
310 * and round to closest integer.
311 *
312 * Return: dividend / divisor rounded to nearest integer
313 */
314 #define DIV64_U64_ROUND_CLOSEST(dividend, divisor) \
315 ({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); })
316
317 /**
318 * DIV_U64_ROUND_CLOSEST - unsigned 64bit divide with 32bit divisor rounded to nearest integer
319 * @dividend: unsigned 64bit dividend
320 * @divisor: unsigned 32bit divisor
321 *
322 * Divide unsigned 64bit dividend by unsigned 32bit divisor
323 * and round to closest integer.
324 *
325 * Return: dividend / divisor rounded to nearest integer
326 */
327 #define DIV_U64_ROUND_CLOSEST(dividend, divisor) \
328 ({ u32 _tmp = (divisor); div_u64((u64)(dividend) + _tmp / 2, _tmp); })
329
330 /**
331 * DIV_S64_ROUND_CLOSEST - signed 64bit divide with 32bit divisor rounded to nearest integer
332 * @dividend: signed 64bit dividend
333 * @divisor: signed 32bit divisor
334 *
335 * Divide signed 64bit dividend by signed 32bit divisor
336 * and round to closest integer.
337 *
338 * Return: dividend / divisor rounded to nearest integer
339 */
340 #define DIV_S64_ROUND_CLOSEST(dividend, divisor)( \
341 { \
342 s64 __x = (dividend); \
343 s32 __d = (divisor); \
344 ((__x > 0) == (__d > 0)) ? \
345 div_s64((__x + (__d / 2)), __d) : \
346 div_s64((__x - (__d / 2)), __d); \
347 } \
348 )
349 #endif /* _LINUX_MATH64_H */
350