DPDK 23.11.2
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rte_sched_common.h
1/* SPDX-License-Identifier: BSD-3-Clause
2 * Copyright(c) 2010-2014 Intel Corporation
3 */
4
5#ifndef __INCLUDE_RTE_SCHED_COMMON_H__
6#define __INCLUDE_RTE_SCHED_COMMON_H__
7
8#ifdef __cplusplus
9extern "C" {
10#endif
11
12#include <stdint.h>
13#include <sys/types.h>
14
15#define __rte_aligned_16 __rte_aligned(16)
16
17#if 0
18static inline uint32_t
19rte_min_pos_4_u16(uint16_t *x)
20{
21 uint32_t pos0, pos1;
22
23 pos0 = (x[0] <= x[1])? 0 : 1;
24 pos1 = (x[2] <= x[3])? 2 : 3;
25
26 return (x[pos0] <= x[pos1])? pos0 : pos1;
27}
28
29#else
30
31/* simplified version to remove branches with CMOV instruction */
32static inline uint32_t
33rte_min_pos_4_u16(uint16_t *x)
34{
35 uint32_t pos0 = 0;
36 uint32_t pos1 = 2;
37
38 if (x[1] <= x[0]) pos0 = 1;
39 if (x[3] <= x[2]) pos1 = 3;
40 if (x[pos1] <= x[pos0]) pos0 = pos1;
41
42 return pos0;
43}
44
45#endif
46
47/*
48 * Compute the Greatest Common Divisor (GCD) of two numbers.
49 * This implementation uses Euclid's algorithm:
50 * gcd(a, 0) = a
51 * gcd(a, b) = gcd(b, a mod b)
52 */
53static inline uint64_t
54rte_get_gcd64(uint64_t a, uint64_t b)
55{
56 uint64_t c;
57
58 if (a == 0)
59 return b;
60 if (b == 0)
61 return a;
62
63 if (a < b) {
64 c = a;
65 a = b;
66 b = c;
67 }
68
69 while (b != 0) {
70 c = a % b;
71 a = b;
72 b = c;
73 }
74
75 return a;
76}
77
78/*
79 * 32-bit version of Greatest Common Divisor (GCD).
80 */
81static inline uint32_t
82rte_get_gcd(uint32_t a, uint32_t b)
83{
84 return rte_get_gcd64(a, b);
85}
86
87/*
88 * Compute the Lowest Common Denominator (LCD) of two numbers.
89 * This implementation computes GCD first:
90 * LCD(a, b) = (a * b) / GCD(a, b)
91 */
92static inline uint32_t
93rte_get_lcd(uint32_t a, uint32_t b)
94{
95 return (a * b) / rte_get_gcd(a, b);
96}
97
98#ifdef __cplusplus
99}
100#endif
101
102#endif /* __INCLUDE_RTE_SCHED_COMMON_H__ */