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#include "libc/stdio.h"
#include "gdt.h"
#include "mem.h"
#include "paging.h"
char show_tics=0;
void schedule(){
}
void clock(){
static int tic=0;
static int sec=0;
tic++;
if(tic>=20){
tic=0;
sec++;
if(show_tics)
putchar('.');
}
schedule();
}
void run_task(int *page_dir, void *task, int task_size){
// Compute various addresses
int*pt_addr=PADDR(page_dir[1]);
void *entry_point=(void*)(PADDR(pt_addr[3]));
void *ustack=(void*)((int)entry_point+0xFF);
// Load the task into memory
memcpy(task,entry_point, task_size);
// Load page directory
asm(
"mov %0, %%eax \n\t"
"mov %%eax,%%cr3 \n\t"
:: "b"(page_dir)
);
// Setup users adresses
// Switch to user task
asm (
"cli \n\t" // Ensure we do not get interrupted
"movl %%ss, %%eax \n\t"
"movl %%eax, %0 \n\t" // Save kernel ss segment into the TSS
"movl %%esp, %1 \n\t" // Save kernel esp into the TSS BEFORE setting up the stack
"pushl $0x33 \n\t" // Push task ss which is 0x30 along with prlv which is 0x3
"pushl %2 \n\t" // Push task esp
"pushfl \n\t" // Retrieve flags
"popl %%eax \n\t"
"orl $0x200, %%eax \n\t" // Enable interrupt for the user task
"and $0xffffbfff, %%eax \n\t" // Clear the NT flags
"push %%eax \n\t" // Push task flags
"push $0x23 \n\t" // Push task cs which is 0x20 along with prlv which is 0x3
"push %3 \n\t" // Push task entry point
"mov $0x2B, %%eax \n\t" // GDT entry 0x28 along with prlv which is 0x3
"mov %%eax, %%ds \n\t" // Setting up user data segment
"iret \n\t" // Launch user task
: "=m" (TSS.ss0), "=m" (TSS.esp0)
: "b" (ustack), "c" (entry_point)
);
}
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