myOS/myos.c at master · Ansersion/myOS · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
#include "myos.h"
#include "stm32f10x.h"


OS_TCB OSTCBTbl[OS_MAX_TASKS]; // (OS Task Control Block Table)
OS_STK TASK_IDLE_STK[TASK_STACK_SIZE]; //("TaskIdle" Stack)
OS_TCB *OSTCBCur; // Pointer to the current running task(OS Task Control Block Current)
OS_TCB *OSTCBNext; // Pointer to the next running task(OS Task Control Block Next)
INT8U OSTaskNext; // Index of the next task
INT32U TaskTickLeft; // Refer to the time ticks left for the current task
INT32U TimeMS;
INT32U TaskTimeSlice;
char * Systick_priority = (char *)0xe000ed23;
// Initialize the stack of a task, it is of much relationship with the specific CPU
OS_STK* OSTaskStkInit(void (*task)(void *p_arg),
	      void *p_arg,
	      OS_STK *p_tos)
{
	OS_STK *stk;
	stk = p_tos;

	*(stk)    = (INT32U)0x01000000L;             // xPSR
	*(--stk)  = (INT32U)task;                    // Entry Point

	// Don't be serious with the value below. They are of random
	*(--stk)  = (INT32U)0xFFFFFFFEL;             // R14 (LR)
	*(--stk)  = (INT32U)0x12121212L;             // R12
	*(--stk)  = (INT32U)0x03030303L;             // R3
	*(--stk)  = (INT32U)0x02020202L;             // R2
	*(--stk)  = (INT32U)0x01010101L;             // R1

	// pointer of the argument
	*(--stk)  = (INT32U)p_arg;                   // R0

	// Don't be serious with the value below. They are of random
	*(--stk)  = (INT32U)0x11111111L;             // R11
	*(--stk)  = (INT32U)0x10101010L;             // R10
	*(--stk)  = (INT32U)0x09090909L;             // R9
	*(--stk)  = (INT32U)0x08080808L;             // R8
	*(--stk)  = (INT32U)0x07070707L;             // R7
	*(--stk)  = (INT32U)0x06060606L;             // R6
	*(--stk)  = (INT32U)0x05050505L;             // R5
	*(--stk)  = (INT32U)0x04040404L;             // R4
	return stk;
}

// Only to initialize the Task Control Block Table
void OSInit(void)
{
	INT8U i;
	OS_ENTER_CRITICAL();
	for(i = 0; i < OS_MAX_TASKS; i++) {
		OSTCBTbl[i].OSTCBStkPtr = (OS_STK*)0;
		OSTCBTbl[i].OSTCBStat = TASK_STATE_CREATING;
	}
	OSInitTaskIdle();
	OSTCBCur = &OSTCBTbl[0];
	OSTCBNext = &OSTCBTbl[0];
	OS_EXIT_CRITICAL();
}

void OSInitTaskIdle(void)
{
	OS_ENTER_CRITICAL();
	OSTCBTbl[0].OSTCBStkPtr = OSTaskStkInit(OS_TaskIdle, (void *)0, (OS_STK*)&TASK_IDLE_STK[TASK_STACK_SIZE - 1]);
	OSTCBTbl[0].OSTCBStat = TASK_STATE_RUNNING;
	OS_EXIT_CRITICAL();
}

void OSTaskCreate(void (*task)(void *p_arg),
		  void *p_arg,
		  OS_STK *p_tos)
{
	OS_STK * tmp;
	INT8U i = 1;
	OS_ENTER_CRITICAL();
	while(OSTCBTbl[i].OSTCBStkPtr != (OS_STK*)0) {
		i++;
	}
	tmp = OSTaskStkInit(task, p_arg, p_tos);
	OSTCBSet(&OSTCBTbl[i], tmp, TASK_STATE_CREATING);
	OS_EXIT_CRITICAL();
}

void OSTCBSet(OS_TCB *p_tcb, OS_STK *p_tos, INT8U task_state)
{
	p_tcb->OSTCBStkPtr = p_tos;
	p_tcb->OSTCBStat = task_state;
}

void OS_TaskIdle(void *p_arg)
{
	p_arg = p_arg; // No use of p_arg, only for avoiding "warning" here.
	for(;;) {
		// OS_ENTER_CRITICAL();
		// Nothing to do
		// OS_EXIT_CRITICAL();
	}
}

// void SysTick_Handler(void)
// {
// 	// OS_ENTER_CRITICAL();
// 	// OS_EXIT_CRITICAL();
// }
void SysTick_Handler(void)
{
	OS_ENTER_CRITICAL();
	if((--TaskTimeSlice) == 0){
		TaskTimeSlice = TASK_TIME_SLICE;
		OSTCBCur = OSTCBNext;
		OSCtxSw();
		OSTaskNext++;
		while(OSTCBTbl[OSTaskNext].OSTCBStkPtr == (OS_STK*)0) {
			OSTaskNext++;
			if(OSTaskNext >= OS_MAX_TASKS) {
				OSTaskNext = 0;
			}
		}
		OSTCBNext = &OSTCBTbl[OSTaskNext];
		TaskTimeSlice = TASK_TIME_SLICE;
	}
	TimeMS++;
	OS_EXIT_CRITICAL();
}

void SysTickInit(INT8U Nms)
{

	OS_ENTER_CRITICAL();

	TimeMS = 0;
	TaskTimeSlice = TASK_TIME_SLICE;

	SysTick->LOAD  = 1000 * Nms - 1;
	*Systick_priority = 0x00;
	SysTick->VAL   = 0;
	SysTick->CTRL = 0x3;
	OS_EXIT_CRITICAL();
}

INT32U GetTime(void)
{
	return TimeMS;
}

void delayMs(volatile INT32U ms)
{
	INT32U tmp;
	tmp = GetTime() + ms;
	while(1){
		if(tmp < GetTime()) break;
	}
}