1 /* $NetBSD: math64.h,v 1.12 2021/12/19 11:48:34 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #ifndef _LINUX_MATH64_H_
33 #define _LINUX_MATH64_H_
34
35 #include <sys/types.h>
36
37 #include <asm/div64.h>
38
39 #include <linux/types.h>
40
41 static inline int64_t
div64_u64(int64_t dividend,uint64_t divisor)42 div64_u64(int64_t dividend, uint64_t divisor)
43 {
44 return dividend / divisor;
45 }
46
47 static inline int64_t
div_u64(int64_t dividend,uint32_t divisor)48 div_u64(int64_t dividend, uint32_t divisor)
49 {
50 return dividend / divisor;
51 }
52
53 static inline int64_t
div64_s64(int64_t dividend,int64_t divisor)54 div64_s64(int64_t dividend, int64_t divisor)
55 {
56 return dividend / divisor;
57 }
58
59 static inline uint64_t
DIV64_U64_ROUND_UP(uint64_t dividend,uint64_t divisor)60 DIV64_U64_ROUND_UP(uint64_t dividend, uint64_t divisor)
61 {
62 return (dividend + (divisor - 1))/divisor;
63 }
64
65 static inline int64_t
div_s64(int64_t dividend,int32_t divisor)66 div_s64(int64_t dividend, int32_t divisor)
67 {
68 return dividend / divisor;
69 }
70
71 static inline uint32_t
div_u64_rem(uint64_t dividend,uint32_t divisor,uint32_t * rem)72 div_u64_rem(uint64_t dividend, uint32_t divisor, uint32_t *rem)
73 {
74 *rem = dividend % divisor;
75 return dividend / divisor;
76 }
77
78 static inline uint64_t
div64_u64_rem(uint64_t dividend,uint64_t divisor,uint64_t * rem)79 div64_u64_rem(uint64_t dividend, uint64_t divisor, uint64_t *rem)
80 {
81 *rem = dividend % divisor;
82 return dividend / divisor;
83 }
84
85 static inline uint64_t
mul_u32_u32(uint32_t a,uint32_t b)86 mul_u32_u32(uint32_t a, uint32_t b)
87 {
88 return (uint64_t)a * (uint64_t)b;
89 }
90
91 static inline uint64_t
mul_u64_u32_div(uint64_t a,uint32_t b,uint32_t div)92 mul_u64_u32_div(uint64_t a, uint32_t b, uint32_t div)
93 {
94 /* XXX implement to account for overflow */
95 return (a * b) / div;
96 }
97
98 /* return floor((a*b) / 2^c) */
99 static inline uint64_t
mul_u64_u32_shr(uint64_t a,uint32_t b,unsigned c)100 mul_u64_u32_shr(uint64_t a, uint32_t b, unsigned c)
101 {
102 /* 2^32 a_hi + a_lo := a */
103 uint64_t a_hi = a >> 32;
104 uint64_t a_lo = a & 0xffffffffU;
105
106 if (c >= 32) {
107 /* (a*b) / 2^c = (a_hi b + a_lo b / 2^32) / 2^{c - 32} */
108 return ((a_hi * b) + ((a_lo * b) >> 32)) >> (c - 32);
109 } else {
110 /* (a*b) / 2^c = 2^{32 - c} a_hi b + a_lo b / 2^c */
111 return ((a_hi * b) << (32 - c)) + ((a_lo * b) >> c);
112 }
113 }
114
115 #endif /* _LINUX_MATH64_H_ */
116