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