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1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MATH64_H
3 #define _LINUX_MATH64_H
5 #include <linux/types.h>
6 #include <linux/math.h>
7 #include <vdso/math64.h>
10 #if BITS_PER_LONG == 64
12 #define div64_long(x, y) div64_s64((x), (y))
13 #define div64_ul(x, y) div64_u64((x), (y))
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
21 * Return: sets ``*remainder``, then returns dividend / divisor
23 * This is commonly provided by 32bit archs to provide an optimized 64bit
26 static inline u64
div_u64_rem(u64 dividend
, u32 divisor
, u32
*remainder
)
28 *remainder
= dividend
% divisor
;
29 return dividend
/ divisor
;
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
38 * Return: sets ``*remainder``, then returns dividend / divisor
40 static inline s64
div_s64_rem(s64 dividend
, s32 divisor
, s32
*remainder
)
42 *remainder
= dividend
% divisor
;
43 return dividend
/ divisor
;
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
52 * Return: sets ``*remainder``, then returns dividend / divisor
54 static inline u64
div64_u64_rem(u64 dividend
, u64 divisor
, u64
*remainder
)
56 *remainder
= dividend
% divisor
;
57 return dividend
/ divisor
;
61 * div64_u64 - unsigned 64bit divide with 64bit divisor
62 * @dividend: unsigned 64bit dividend
63 * @divisor: unsigned 64bit divisor
65 * Return: dividend / divisor
67 static inline u64
div64_u64(u64 dividend
, u64 divisor
)
69 return dividend
/ divisor
;
73 * div64_s64 - signed 64bit divide with 64bit divisor
74 * @dividend: signed 64bit dividend
75 * @divisor: signed 64bit divisor
77 * Return: dividend / divisor
79 static inline s64
div64_s64(s64 dividend
, s64 divisor
)
81 return dividend
/ divisor
;
84 #elif BITS_PER_LONG == 32
86 #define div64_long(x, y) div_s64((x), (y))
87 #define div64_ul(x, y) div_u64((x), (y))
90 static inline u64
div_u64_rem(u64 dividend
, u32 divisor
, u32
*remainder
)
92 *remainder
= do_div(dividend
, divisor
);
98 extern s64
div_s64_rem(s64 dividend
, s32 divisor
, s32
*remainder
);
101 #ifndef div64_u64_rem
102 extern u64
div64_u64_rem(u64 dividend
, u64 divisor
, u64
*remainder
);
106 extern u64
div64_u64(u64 dividend
, u64 divisor
);
110 extern s64
div64_s64(s64 dividend
, s64 divisor
);
113 #endif /* BITS_PER_LONG */
116 * div_u64 - unsigned 64bit divide with 32bit divisor
117 * @dividend: unsigned 64bit dividend
118 * @divisor: unsigned 32bit divisor
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
125 static inline u64
div_u64(u64 dividend
, u32 divisor
)
128 return div_u64_rem(dividend
, divisor
, &remainder
);
133 * div_s64 - signed 64bit divide with 32bit divisor
134 * @dividend: signed 64bit dividend
135 * @divisor: signed 32bit divisor
138 static inline s64
div_s64(s64 dividend
, s32 divisor
)
141 return div_s64_rem(dividend
, divisor
, &remainder
);
145 u32
iter_div_u64_rem(u64 dividend
, u32 divisor
, u64
*remainder
);
149 * Many a GCC version messes this up and generates a 64x64 mult :-(
151 static inline u64
mul_u32_u32(u32 a
, u32 b
)
157 #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
159 #ifndef mul_u64_u32_shr
160 static inline u64
mul_u64_u32_shr(u64 a
, u32 mul
, unsigned int shift
)
162 return (u64
)(((unsigned __int128
)a
* mul
) >> shift
);
164 #endif /* mul_u64_u32_shr */
166 #ifndef mul_u64_u64_shr
167 static inline u64
mul_u64_u64_shr(u64 a
, u64 mul
, unsigned int shift
)
169 return (u64
)(((unsigned __int128
)a
* mul
) >> shift
);
171 #endif /* mul_u64_u64_shr */
175 #ifndef mul_u64_u32_shr
176 static inline u64
mul_u64_u32_shr(u64 a
, u32 mul
, unsigned int shift
)
184 ret
= mul_u32_u32(al
, mul
) >> shift
;
186 ret
+= mul_u32_u32(ah
, mul
) << (32 - shift
);
190 #endif /* mul_u64_u32_shr */
192 #ifndef mul_u64_u64_shr
193 static inline u64
mul_u64_u64_shr(u64 a
, u64 b
, unsigned int shift
)
204 } rl
, rm
, rn
, rh
, a0
, b0
;
210 rl
.ll
= mul_u32_u32(a0
.l
.low
, b0
.l
.low
);
211 rm
.ll
= mul_u32_u32(a0
.l
.low
, b0
.l
.high
);
212 rn
.ll
= mul_u32_u32(a0
.l
.high
, b0
.l
.low
);
213 rh
.ll
= mul_u32_u32(a0
.l
.high
, b0
.l
.high
);
216 * Each of these lines computes a 64-bit intermediate result into "c",
217 * starting at bits 32-95. The low 32-bits go into the result of the
218 * multiplication, the high 32-bits are carried into the next step.
220 rl
.l
.high
= c
= (u64
)rl
.l
.high
+ rm
.l
.low
+ rn
.l
.low
;
221 rh
.l
.low
= c
= (c
>> 32) + rm
.l
.high
+ rn
.l
.high
+ rh
.l
.low
;
222 rh
.l
.high
= (c
>> 32) + rh
.l
.high
;
225 * The 128-bit result of the multiplication is in rl.ll and rh.ll,
226 * shift it right and throw away the high part of the result.
231 return (rl
.ll
>> shift
) | (rh
.ll
<< (64 - shift
));
232 return rh
.ll
>> (shift
& 63);
234 #endif /* mul_u64_u64_shr */
238 #ifndef mul_s64_u64_shr
239 static inline u64
mul_s64_u64_shr(s64 a
, u64 b
, unsigned int shift
)
244 * Extract the sign before the multiplication and put it back
245 * afterwards if needed.
247 ret
= mul_u64_u64_shr(abs(a
), b
, shift
);
254 #endif /* mul_s64_u64_shr */
256 #ifndef mul_u64_u32_div
257 static inline u64
mul_u64_u32_div(u64 a
, u32 mul
, u32 divisor
)
271 rl
.ll
= mul_u32_u32(u
.l
.low
, mul
);
272 rh
.ll
= mul_u32_u32(u
.l
.high
, mul
) + rl
.l
.high
;
274 /* Bits 32-63 of the result will be in rh.l.low. */
275 rl
.l
.high
= do_div(rh
.ll
, divisor
);
277 /* Bits 0-31 of the result will be in rl.l.low. */
278 do_div(rl
.ll
, divisor
);
280 rl
.l
.high
= rh
.l
.low
;
283 #endif /* mul_u64_u32_div */
285 u64
mul_u64_u64_div_u64(u64 a
, u64 mul
, u64 div
);
287 #define DIV64_U64_ROUND_UP(ll, d) \
288 ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); })
291 * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer
292 * @dividend: unsigned 64bit dividend
293 * @divisor: unsigned 64bit divisor
295 * Divide unsigned 64bit dividend by unsigned 64bit divisor
296 * and round to closest integer.
298 * Return: dividend / divisor rounded to nearest integer
300 #define DIV64_U64_ROUND_CLOSEST(dividend, divisor) \
301 ({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); })
304 * DIV_S64_ROUND_CLOSEST - signed 64bit divide with 32bit divisor rounded to nearest integer
305 * @dividend: signed 64bit dividend
306 * @divisor: signed 32bit divisor
308 * Divide signed 64bit dividend by signed 32bit divisor
309 * and round to closest integer.
311 * Return: dividend / divisor rounded to nearest integer
313 #define DIV_S64_ROUND_CLOSEST(dividend, divisor)( \
315 s64 __x = (dividend); \
316 s32 __d = (divisor); \
317 ((__x > 0) == (__d > 0)) ? \
318 div_s64((__x + (__d / 2)), __d) : \
319 div_s64((__x - (__d / 2)), __d); \
322 #endif /* _LINUX_MATH64_H */