Multitasking works!

1 files changed, 62 insertions, 37 deletions

diff --git a/src/core/scheduler.c b/src/core/scheduler.c
index 0a8c5c7..fffeaf2 100644
--- a/src/core/scheduler.c
+++ b/src/core/scheduler.c
@@ -9,16 +9,14 @@ PROC procs[MAX_PROC];
 u16 current_id;
 u16 nproc;
 
-void schedule(){
+void schedule(u32 *stack){
   // Note that this function is called by clock
   // clock is called by INT_CLOCK (core/int.S)
   // which store all the process information on
   // the stack. Thus, knowing the C calling conventions
   // and that schedule() is call by two functions with no parameters,
   // the first process register can be accessed by ebp+2
-  u32 *stack;
-  asm("mov %%ebp, %0":"=r" (stack));
-  
+
   // No proc to schedule
   if(nproc<2)
     return;
@@ -47,7 +45,8 @@ void schedule(){
   current_id++;
   if(current_id>=nproc)
     current_id=0;
-
+  p=&procs[current_id];
+ 
   // Have a clean stack on next interrupt
   TSS.esp0=(u32)stack+19;
   asm("mov %%ss, %0": "=m" (TSS.ss0));
@@ -58,13 +57,16 @@ void schedule(){
 
   // Perform task switch
   asm(
-    "mov %0, %%esi    \n\t"
+    "push %0          \n\t"
     "jmp task_switch  \n\t"
     :: "a" (p)
   );
 }
 
 void clock(){
+  u32* stack;
+  asm("mov %%ebp, %0":"=r" (stack));
+
   static int tic=0;
   static int sec=0;
   tic++;
@@ -75,46 +77,69 @@ void clock(){
       putchar('.');
   }
   if(scheduler_on==1)
-    schedule();
+    schedule(stack);
 }
 
-void run_task(int *page_dir, void *task, int task_size){
+void task_create(int *page_dir, void *task, int task_size){
+  if(nproc<=MAX_PROC){
     // Compute various addresses
-    int*pt_addr=(int*)PADDR(page_dir[1]);
-    void *entry_point=(void*)(PADDR(pt_addr[3]));
-    void *ustack=(void*)((int)entry_point+0xFF);
+    void *entry_point=PAGING_ENTRY_POINT_VIRT;
+    void *ustack=(void*)(PAGING_ENTRY_POINT_VIRT+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)
-    );
+    memcpy(task,PAGING_ENTRY_POINT_PHY(page_dir), task_size);
 
-     // Setup users adresses
- 
-    // Switch to user task
+    // Setup process registers
+    PROC *p=&procs[nproc];
+    p->regs.cs=0x23; // Task cs which is 0x30 along with prlv which is 0x3
+    p->regs.eip=entry_point;
+    p->regs.ss=0x33; // Task ss which is 0x20 along with prlv which is 0x3
+    p->regs.esp=ustack; // Stack is here for now...
+    p->regs.ds=0x2B; // GDT entry 0x28 along with prlv which is 0x3
+    p->regs.eax=0;
+    p->regs.ebx=0;
+    p->regs.ecx=0;
+    p->regs.edx=0;
+
+    // Manage eflags
+    u32 eflags;
     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)
-  );
+    "mov %%eax, %0            \n\t" // Get flags into eflag
+    : "=m" (eflags)
+    );
+    p->regs.eflags=eflags;
+
+    // Setup other attributes
+    p->id=nproc;
+    p->pid=nproc;
+    p->page_dir=page_dir;
+    nproc++;
+  }
+}
+
+void scheduler_start(){
+  if(nproc>0){
+    asm("cli");
+    scheduler_on=1; // Enable scheduling
+    u32 *stack;
+    asm("mov %%ebp, %0":"=r" (stack));
+    TSS.esp0=(u32)stack+1; // Remove ebp (c call convention)
+    asm("mov %%ss, %0": "=m" (TSS.ss0));
+
+    current_id=1;
+    PROC *p=&procs[current_id];
+
+    // Ensure interrupts are activated and NT flag is clear
+    p->regs.eflags|=0x200;
+    p->regs.eflags&=0xffffbfff;
+    asm(
+      "push %0    \n\t"
+      "jmp task_switch"
+      :: "a" (p)
+      );
+  }
 }
\ No newline at end of file