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 __rte_aligned(16)
16
17 #if 0
18 static inline uint32_t
19 rte_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 */
32 static inline uint32_t
rte_min_pos_4_u16(uint16_t * x)33 rte_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 *
53 */
54 static inline uint32_t
rte_get_gcd(uint32_t a,uint32_t b)55 rte_get_gcd(uint32_t a, uint32_t b)
56 {
57 uint32_t c;
58
59 if (a == 0)
60 return b;
61 if (b == 0)
62 return a;
63
64 if (a < b) {
65 c = a;
66 a = b;
67 b = c;
68 }
69
70 while (b != 0) {
71 c = a % b;
72 a = b;
73 b = c;
74 }
75
76 return a;
77 }
78
79 /*
80 * Compute the Lowest Common Denominator (LCD) of two numbers.
81 * This implementation computes GCD first:
82 * LCD(a, b) = (a * b) / GCD(a, b)
83 *
84 */
85 static inline uint32_t
rte_get_lcd(uint32_t a,uint32_t b)86 rte_get_lcd(uint32_t a, uint32_t b)
87 {
88 return (a * b) / rte_get_gcd(a, b);
89 }
90
91 #ifdef __cplusplus
92 }
93 #endif
94
95 #endif /* __INCLUDE_RTE_SCHED_COMMON_H__ */
96