DPDK  18.05.1
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
9 extern "C" {
10 #endif
11 
12 #include <stdint.h>
13 #include <sys/types.h>
14 
15 #define __rte_aligned_16 __attribute__((__aligned__(16)))
16 
17 static inline uint32_t
18 rte_sched_min_val_2_u32(uint32_t x, uint32_t y)
19 {
20  return (x < y)? x : y;
21 }
22 
23 #if 0
24 static inline uint32_t
25 rte_min_pos_4_u16(uint16_t *x)
26 {
27  uint32_t pos0, pos1;
28 
29  pos0 = (x[0] <= x[1])? 0 : 1;
30  pos1 = (x[2] <= x[3])? 2 : 3;
31 
32  return (x[pos0] <= x[pos1])? pos0 : pos1;
33 }
34 
35 #else
36 
37 /* simplified version to remove branches with CMOV instruction */
38 static inline uint32_t
39 rte_min_pos_4_u16(uint16_t *x)
40 {
41  uint32_t pos0 = 0;
42  uint32_t pos1 = 2;
43 
44  if (x[1] <= x[0]) pos0 = 1;
45  if (x[3] <= x[2]) pos1 = 3;
46  if (x[pos1] <= x[pos0]) pos0 = pos1;
47 
48  return pos0;
49 }
50 
51 #endif
52 
53 /*
54  * Compute the Greatest Common Divisor (GCD) of two numbers.
55  * This implementation uses Euclid's algorithm:
56  * gcd(a, 0) = a
57  * gcd(a, b) = gcd(b, a mod b)
58  *
59  */
60 static inline uint32_t
61 rte_get_gcd(uint32_t a, uint32_t b)
62 {
63  uint32_t c;
64 
65  if (a == 0)
66  return b;
67  if (b == 0)
68  return a;
69 
70  if (a < b) {
71  c = a;
72  a = b;
73  b = c;
74  }
75 
76  while (b != 0) {
77  c = a % b;
78  a = b;
79  b = c;
80  }
81 
82  return a;
83 }
84 
85 /*
86  * Compute the Lowest Common Denominator (LCD) of two numbers.
87  * This implementation computes GCD first:
88  * LCD(a, b) = (a * b) / GCD(a, b)
89  *
90  */
91 static inline uint32_t
92 rte_get_lcd(uint32_t a, uint32_t b)
93 {
94  return (a * b) / rte_get_gcd(a, b);
95 }
96 
97 #ifdef __cplusplus
98 }
99 #endif
100 
101 #endif /* __INCLUDE_RTE_SCHED_COMMON_H__ */