aboutsummaryrefslogtreecommitdiff
path: root/include/linux/math64.h
blob: 2928f03d6d46a124b177bd299eced044a7789b11 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MATH64_H
#define _LINUX_MATH64_H

#include <linux/types.h>
#include <linux/math.h>
#include <vdso/math64.h>
#include <asm/div64.h>

#if BITS_PER_LONG == 64

#define div64_long(x, y) div64_s64((x), (y))
#define div64_ul(x, y)   div64_u64((x), (y))

/**
 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
 * @dividend: unsigned 64bit dividend
 * @divisor: unsigned 32bit divisor
 * @remainder: pointer to unsigned 32bit remainder
 *
 * Return: sets ``*remainder``, then returns dividend / divisor
 *
 * This is commonly provided by 32bit archs to provide an optimized 64bit
 * divide.
 */
static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
	*remainder = dividend % divisor;
	return dividend / divisor;
}

/*
 * div_s64_rem - signed 64bit divide with 32bit divisor with remainder
 * @dividend: signed 64bit dividend
 * @divisor: signed 32bit divisor
 * @remainder: pointer to signed 32bit remainder
 *
 * Return: sets ``*remainder``, then returns dividend / divisor
 */
static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
{
	*remainder = dividend % divisor;
	return dividend / divisor;
}

/*
 * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
 * @dividend: unsigned 64bit dividend
 * @divisor: unsigned 64bit divisor
 * @remainder: pointer to unsigned 64bit remainder
 *
 * Return: sets ``*remainder``, then returns dividend / divisor
 */
static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
{
	*remainder = dividend % divisor;
	return dividend / divisor;
}

/*
 * div64_u64 - unsigned 64bit divide with 64bit divisor
 * @dividend: unsigned 64bit dividend
 * @divisor: unsigned 64bit divisor
 *
 * Return: dividend / divisor
 */
static inline u64 div64_u64(u64 dividend, u64 divisor)
{
	return dividend / divisor;
}

/*
 * div64_s64 - signed 64bit divide with 64bit divisor
 * @dividend: signed 64bit dividend
 * @divisor: signed 64bit divisor
 *
 * Return: dividend / divisor
 */
static inline s64 div64_s64(s64 dividend, s64 divisor)
{
	return dividend / divisor;
}

#elif BITS_PER_LONG == 32

#define div64_long(x, y) div_s64((x), (y))
#define div64_ul(x, y)   div_u64((x), (y))

#ifndef div_u64_rem
static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
	*remainder = do_div(dividend, divisor);
	return dividend;
}
#endif

#ifndef div_s64_rem
extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
#endif

#ifndef div64_u64_rem
extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder);
#endif

#ifndef div64_u64
extern u64 div64_u64(u64 dividend, u64 divisor);
#endif

#ifndef div64_s64
extern s64 div64_s64(s64 dividend, s64 divisor);
#endif

#endif /* BITS_PER_LONG */

/**
 * div_u64 - unsigned 64bit divide with 32bit divisor
 * @dividend: unsigned 64bit dividend
 * @divisor: unsigned 32bit divisor
 *
 * This is the most common 64bit divide and should be used if possible,
 * as many 32bit archs can optimize this variant better than a full 64bit
 * divide.
 */
#ifndef div_u64
static inline u64 div_u64(u64 dividend, u32 divisor)
{
	u32 remainder;
	return div_u64_rem(dividend, divisor, &remainder);
}
#endif

/**
 * div_s64 - signed 64bit divide with 32bit divisor
 * @dividend: signed 64bit dividend
 * @divisor: signed 32bit divisor
 */
#ifndef div_s64
static inline s64 div_s64(s64 dividend, s32 divisor)
{
	s32 remainder;
	return div_s64_rem(dividend, divisor, &remainder);
}
#endif

u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);

#ifndef mul_u32_u32
/*
 * Many a GCC version messes this up and generates a 64x64 mult :-(
 */
static inline u64 mul_u32_u32(u32 a, u32 b)
{
	return (u64)a * b;
}
#endif

#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)

#ifndef mul_u64_u32_shr
static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
{
	return (u64)(((unsigned __int128)a * mul) >> shift);
}
#endif /* mul_u64_u32_shr */

#ifndef mul_u64_u64_shr
static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
{
	return (u64)(((unsigned __int128)a * mul) >> shift);
}
#endif /* mul_u64_u64_shr */

#else

#ifndef mul_u64_u32_shr
static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
{
	u32 ah, al;
	u64 ret;

	al = a;
	ah = a >> 32;

	ret = mul_u32_u32(al, mul) >> shift;
	if (ah)
		ret += mul_u32_u32(ah, mul) << (32 - shift);

	return ret;
}
#endif /* mul_u64_u32_shr */

#ifndef mul_u64_u64_shr
static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift)
{
	union {
		u64 ll;
		struct {
#ifdef __BIG_ENDIAN
			u32 high, low;
#else
			u32 low, high;
#endif
		} l;
	} rl, rm, rn, rh, a0, b0;
	u64 c;

	a0.ll = a;
	b0.ll = b;

	rl.ll = mul_u32_u32(a0.l.low, b0.l.low);
	rm.ll = mul_u32_u32(a0.l.low, b0.l.high);
	rn.ll = mul_u32_u32(a0.l.high, b0.l.low);
	rh.ll = mul_u32_u32(a0.l.high, b0.l.high);

	/*
	 * Each of these lines computes a 64-bit intermediate result into "c",
	 * starting at bits 32-95.  The low 32-bits go into the result of the
	 * multiplication, the high 32-bits are carried into the next step.
	 */
	rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low;
	rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low;
	rh.l.high = (c >> 32) + rh.l.high;

	/*
	 * The 128-bit result of the multiplication is in rl.ll and rh.ll,
	 * shift it right and throw away the high part of the result.
	 */
	if (shift == 0)
		return rl.ll;
	if (shift < 64)
		return (rl.ll >> shift) | (rh.ll << (64 - shift));
	return rh.ll >> (shift & 63);
}
#endif /* mul_u64_u64_shr */

#endif

#ifndef mul_s64_u64_shr
static inline u64 mul_s64_u64_shr(s64 a, u64 b, unsigned int shift)
{
	u64 ret;

	/*
	 * Extract the sign before the multiplication and put it back
	 * afterwards if needed.
	 */
	ret = mul_u64_u64_shr(abs(a), b, shift);

	if (a < 0)
		ret = -((s64) ret);

	return ret;
}
#endif /* mul_s64_u64_shr */

#ifndef mul_u64_u32_div
static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
{
	union {
		u64 ll;
		struct {
#ifdef __BIG_ENDIAN
			u32 high, low;
#else
			u32 low, high;
#endif
		} l;
	} u, rl, rh;

	u.ll = a;
	rl.ll = mul_u32_u32(u.l.low, mul);
	rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high;

	/* Bits 32-63 of the result will be in rh.l.low. */
	rl.l.high = do_div(rh.ll, divisor);

	/* Bits 0-31 of the result will be in rl.l.low.	*/
	do_div(rl.ll, divisor);

	rl.l.high = rh.l.low;
	return rl.ll;
}
#endif /* mul_u64_u32_div */

u64 mul_u64_u64_div_u64(u64 a, u64 mul, u64 div);

#define DIV64_U64_ROUND_UP(ll, d)	\
	({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); })

/**
 * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer
 * @dividend: unsigned 64bit dividend
 * @divisor: unsigned 64bit divisor
 *
 * Divide unsigned 64bit dividend by unsigned 64bit divisor
 * and round to closest integer.
 *
 * Return: dividend / divisor rounded to nearest integer
 */
#define DIV64_U64_ROUND_CLOSEST(dividend, divisor)	\
	({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); })

/*
 * DIV_S64_ROUND_CLOSEST - signed 64bit divide with 32bit divisor rounded to nearest integer
 * @dividend: signed 64bit dividend
 * @divisor: signed 32bit divisor
 *
 * Divide signed 64bit dividend by signed 32bit divisor
 * and round to closest integer.
 *
 * Return: dividend / divisor rounded to nearest integer
 */
#define DIV_S64_ROUND_CLOSEST(dividend, divisor)(	\
{							\
	s64 __x = (dividend);				\
	s32 __d = (divisor);				\
	((__x > 0) == (__d > 0)) ?			\
		div_s64((__x + (__d / 2)), __d) :	\
		div_s64((__x - (__d / 2)), __d);	\
}							\
)
#endif /* _LINUX_MATH64_H */