1 /*- 2 * Copyright (c) 2007 Cisco Systems, Inc. All rights reserved. 3 * Copyright (c) 2014 Mellanox Technologies, Ltd. All rights reserved. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice unmodified, this list of conditions, and the following 11 * disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #ifndef _LINUX_MATH64_H 29 #define _LINUX_MATH64_H 30 31 #include <linux/types.h> 32 #include <linux/bitops.h> 33 34 #if BITS_PER_LONG == 64 35 36 # define do_div(n, base) ({ \ 37 uint32_t __base = (base); \ 38 uint32_t __rem; \ 39 __rem = ((uint64_t)(n)) % __base; \ 40 (n) = ((uint64_t)(n)) / __base; \ 41 __rem; \ 42 }) 43 44 /** 45 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder 46 * 47 * This is commonly provided by 32bit archs to provide an optimized 64bit 48 * divide. 49 */ 50 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) 51 { 52 *remainder = dividend % divisor; 53 return dividend / divisor; 54 } 55 56 57 #elif BITS_PER_LONG == 32 58 59 static uint32_t __div64_32(uint64_t *n, uint32_t base) 60 { 61 uint64_t rem = *n; 62 uint64_t b = base; 63 uint64_t res, d = 1; 64 uint32_t high = rem >> 32; 65 66 /* Reduce the thing a bit first */ 67 res = 0; 68 if (high >= base) { 69 high /= base; 70 res = (uint64_t) high << 32; 71 rem -= (uint64_t) (high*base) << 32; 72 } 73 74 while ((int64_t)b > 0 && b < rem) { 75 b = b+b; 76 d = d+d; 77 } 78 79 do { 80 if (rem >= b) { 81 rem -= b; 82 res += d; 83 } 84 b >>= 1; 85 d >>= 1; 86 } while (d); 87 88 *n = res; 89 return rem; 90 } 91 92 # define do_div(n, base) ({ \ 93 uint32_t __base = (base); \ 94 uint32_t __rem; \ 95 (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \ 96 if (likely(((n) >> 32) == 0)) { \ 97 __rem = (uint32_t)(n) % __base; \ 98 (n) = (uint32_t)(n) / __base; \ 99 } else \ 100 __rem = __div64_32(&(n), __base); \ 101 __rem; \ 102 }) 103 104 #ifndef div_u64_rem 105 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) 106 { 107 *remainder = do_div(dividend, divisor); 108 return dividend; 109 } 110 #endif 111 112 #endif /* BITS_PER_LONG */ 113 114 115 116 /** 117 ** div_u64 - unsigned 64bit divide with 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 124 125 static inline u64 div_u64(u64 dividend, u32 divisor) 126 { 127 u32 remainder; 128 return div_u64_rem(dividend, divisor, &remainder); 129 } 130 #endif 131 132 #endif /* _LINUX_MATH64_H */ 133