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// http://hosted.cjmovie.net/TutMultitask.htm
//
//
#include "kernel.h"
#include "../lib/logger/log.h" // logger facilities
#define FOOLOS_MODULE_NAME "task"
int started;
void task_test1()
{
uint16_t c1;
while(1)
{
c1++;
asm("cli");
PutString("task1: %03d", 0,560,0xffffff, c1/100);
asm("sti");
}
}
void task_test2()
{
uint16_t c2;
while(1)
{
c2++;
asm("cli");
PutString("task2: %03d", 0,580,0xffffff, c2/100);
asm("sti");
}
}
//////////////
//
typedef struct{ //Simple structure for a thread
unsigned int esp0; //Stack for kernel
unsigned int esp3; //Stack for process
} Thread;
Thread Threads[2]; //Space for our simple threads. Just 2!
int CurrentTask = -1; //The thread currenlty running (-1 == none)
void task_create(int pid,void(*thread)())
{
unsigned int *stack;
Threads[pid].esp0 = pmmngr_alloc_block();
stack = (unsigned int*)Threads[pid].esp0+4000; //This makes a pointer to the stack for us
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"new task : stack: 0x%08X ", stack);
//First, this stuff is pushed by the processor
*--stack = 0x0202; //This is EFLAGS
*--stack = 0x08; //This is CS, our code segment
*--stack = (uint32_t)thread; //This is EIP
//Next, the stuff pushed by 'pusha'
*--stack = 0; //EDI
*--stack = 0; //ESI
*--stack = 0; //EBP
*--stack = 0; //Just an offset, no value
*--stack = 0; //EBX
*--stack = 0; //EDX
*--stack = 0; //ECX
*--stack = 0; //EAX
//Now these are the data segments pushed by the IRQ handler
/*
*--stack = 0x10; //DS
*--stack = 0x10; //ES
*--stack = 0x10; //FS
*--stack = 0x10; //GS
*/
Threads[pid].esp0 = (uint32_t)stack; //Update the stack pointer
};
uint32_t task_switch_next(uint32_t oldesp)
{
if(started!=0xabcde) return oldesp;
if(CurrentTask != -1){ //Were we even running a task?
Threads[CurrentTask].esp0 =oldesp; //Save the new esp for the thread
//Now switch what task we're on
if(CurrentTask == 0)CurrentTask = 1;
else CurrentTask = 0;
} else{
CurrentTask = 0; //We just started multi-tasking, start with task 0
}
uint32_t esp=0;
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_FINE,"oldesp: 0x%08X saved / next task: %d (esp: 0x%08X) ",oldesp, CurrentTask,Threads[CurrentTask].esp0);
return Threads[CurrentTask].esp0; //Return new stack pointer to ASM
}
void stack_trace(uint32_t *stack,int size)
{
for(int i=size;i>=0;i--)
{
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"stack: 0x%08X -> 0x%08X", stack, *stack);
stack++;
}
}
void task_init()
{
log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"init multitasking.");
task_create(0,task_test1);
task_create(1,task_test2);
started=0xabcde;
}
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