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 42 div64_u64(int64_t dividend, uint64_t divisor) 43 { 44 return dividend / divisor; 45 } 46 47 static inline int64_t 48 div_u64(int64_t dividend, uint32_t divisor) 49 { 50 return dividend / divisor; 51 } 52 53 static inline int64_t 54 div64_s64(int64_t dividend, int64_t divisor) 55 { 56 return dividend / divisor; 57 } 58 59 static inline uint64_t 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 66 div_s64(int64_t dividend, int32_t divisor) 67 { 68 return dividend / divisor; 69 } 70 71 static inline uint32_t 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 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 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 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 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