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os_prio.c
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1 /*
2 ************************************************************************************************************************
3 * uC/OS-III
4 * The Real-Time Kernel
5 *
6 * (c) Copyright 2009-2012; Micrium, Inc.; Weston, FL
7 * All rights reserved. Protected by international copyright laws.
8 *
9 * PRIORITY MANAGEMENT
10 *
11 * File : OS_PRIO.C
12 * By : JJL
13 * Version : V3.03.00
14 *
15 * LICENSING TERMS:
16 * ---------------
17 * uC/OS-III is provided in source form for FREE short-term evaluation, for educational use or
18 * for peaceful research. If you plan or intend to use uC/OS-III in a commercial application/
19 * product then, you need to contact Micrium to properly license uC/OS-III for its use in your
20 * application/product. We provide ALL the source code for your convenience and to help you
21 * experience uC/OS-III. The fact that the source is provided does NOT mean that you can use
22 * it commercially without paying a licensing fee.
23 *
24 * Knowledge of the source code may NOT be used to develop a similar product.
25 *
26 * Please help us continue to provide the embedded community with the finest software available.
27 * Your honesty is greatly appreciated.
28 *
29 * You can contact us at www.micrium.com, or by phone at +1 (954) 217-2036.
30 ************************************************************************************************************************
31 */
32 
33 #define MICRIUM_SOURCE
34 #include <os.h>
35 
36 #ifdef VSC_INCLUDE_SOURCE_FILE_NAMES
37 const CPU_CHAR *os_prio__c = "$Id: $";
38 #endif
39 
40 
41 CPU_DATA OSPrioTbl[OS_PRIO_TBL_SIZE]; /* Declare the array local to this file to allow for ... */
42  /* ... optimization. In other words, this allows the ... */
43  /* ... table to be located in fast memory */
44 
45 /*
46 ************************************************************************************************************************
47 * INITIALIZE THE PRIORITY LIST
48 *
49 * Description: This function is called by uC/OS-III to initialize the list of ready priorities.
50 *
51 * Arguments : none
52 *
53 * Returns : none
54 *
55 * Note : This function is INTERNAL to uC/OS-III and your application should not call it.
56 ************************************************************************************************************************
57 */
58 
59 void OS_PrioInit (void)
60 {
61  CPU_DATA i;
62 
63 
64  /* Clear the bitmap table ... no task is ready */
65  for (i = 0u; i < OS_PRIO_TBL_SIZE; i++) {
66  OSPrioTbl[i] = (CPU_DATA)0;
67  }
68 }
69 
70 /*
71 ************************************************************************************************************************
72 * GET HIGHEST PRIORITY TASK WAITING
73 *
74 * Description: This function is called by other uC/OS-III services to determine the highest priority task
75 * waiting on the event.
76 *
77 * Arguments : none
78 *
79 * Returns : The priority of the Highest Priority Task (HPT) waiting for the event
80 *
81 * Note(s) : 1) This function is INTERNAL to uC/OS-III and your application MUST NOT call it.
82 ************************************************************************************************************************
83 */
84 
85 OS_PRIO OS_PrioGetHighest (void)
86 {
87  CPU_DATA *p_tbl;
88  OS_PRIO prio;
89 
90 
91  prio = (OS_PRIO)0;
92  p_tbl = &OSPrioTbl[0];
93  while (*p_tbl == (CPU_DATA)0) { /* Search the bitmap table for the highest priority */
94  prio += DEF_INT_CPU_NBR_BITS; /* Compute the step of each CPU_DATA entry */
95  p_tbl++;
96  }
97  prio += (OS_PRIO)CPU_CntLeadZeros(*p_tbl); /* Find the position of the first bit set at the entry */
98  return (prio);
99 }
100 
101 /*
102 ************************************************************************************************************************
103 * INSERT PRIORITY
104 *
105 * Description: This function is called to insert a priority in the priority table.
106 *
107 * Arguments : prio is the priority to insert
108 *
109 * Returns : none
110 *
111 * Note(s) : 1) This function is INTERNAL to uC/OS-III and your application MUST NOT call it.
112 ************************************************************************************************************************
113 */
114 
115 void OS_PrioInsert (OS_PRIO prio)
116 {
117  CPU_DATA bit;
118  CPU_DATA bit_nbr;
119  OS_PRIO ix;
120 
121 
122  ix = prio / DEF_INT_CPU_NBR_BITS;
123  bit_nbr = (CPU_DATA)prio & (DEF_INT_CPU_NBR_BITS - 1u);
124  bit = 1u;
125  bit <<= (DEF_INT_CPU_NBR_BITS - 1u) - bit_nbr;
126  OSPrioTbl[ix] |= bit;
127 }
128 
129 /*
130 ************************************************************************************************************************
131 * REMOVE PRIORITY
132 *
133 * Description: This function is called to remove a priority in the priority table.
134 *
135 * Arguments : prio is the priority to remove
136 *
137 * Returns : none
138 *
139 * Note(s) : 1) This function is INTERNAL to uC/OS-III and your application MUST NOT call it.
140 ************************************************************************************************************************
141 */
142 
143 void OS_PrioRemove (OS_PRIO prio)
144 {
145  CPU_DATA bit;
146  CPU_DATA bit_nbr;
147  OS_PRIO ix;
148 
149 
150  ix = prio / DEF_INT_CPU_NBR_BITS;
151  bit_nbr = (CPU_DATA)prio & (DEF_INT_CPU_NBR_BITS - 1u);
152  bit = 1u;
153  bit <<= (DEF_INT_CPU_NBR_BITS - 1u) - bit_nbr;
154  OSPrioTbl[ix] &= ~bit;
155 }