Massively Improved Multitasking

arch/i686/interrupts/idt.c

@@ -158,7 +158,7 @@ static void add_irqs()
         add_entry(entry, i);
     }
 
-    entry = generate_entry(true, irq0, 0xE, 0, 0x8);
+    entry = generate_entry(true, irq0, 0xE, 0x3, 0x8);
     add_entry(entry, IRQ0);
 
     entry = generate_entry(true, keyboard_interrupt, 0xE, 0, 0x8);

arch/i686/interrupts/irq0.s

@@ -10,8 +10,29 @@
 .extern cs
 .extern eip 
 
+.section .bss
+.align 16 
+task_stack_bottom:
+.skip 4096
+task_stack_top:
+
+.skip 4
+
+temp_esp:
+
+.skip 4
+
+.section .text
 irq0:
+mov %esp, (temp_esp)
+mov $task_stack_top, %esp
+
 pusha
+mov temp_esp, %eax
+push %eax
+push 8(%eax)
+push 4(%eax)
+push  (%eax)
 
 mov $0x10, %eax
 mov %ax, %ds
@@ -24,16 +45,18 @@ call _switch_task
 iret
 
 jump_kernel:
-mov $0x20, %eax
-outb %al, $0x20
-
 mov (ss), %eax
 mov %ax, %ds
 mov %ax, %es
 mov %ax, %fs
 mov %ax, %gs
+mov %ax, %ss
 
 pop %eax
+
+mov $0x20, %eax
+outb %al, $0x20
+
 popa
 
 mov (esp), %esp
@@ -45,9 +68,6 @@ push (eip)
 iret
 
 jump_user:
-mov $0x20, %eax
-outb %al, $0x20
-
 mov (ss), %eax
 mov %ax, %ds
 mov %ax, %es
@@ -55,6 +75,10 @@ mov %ax, %fs
 mov %ax, %gs
 
 pop %eax
+
+mov $0x20, %eax
+outb %al, $0x20
+
 popa
 
 push (ss)

arch/i686/interrupts/syscall.s

@@ -10,10 +10,10 @@ syscall_stack_top:
 .global syscall
 syscall:
 mov $0x10, %edx
-mov %ax, %ds
-mov %ax, %es
-mov %ax, %fs
-mov %ax, %gs
+mov %dx, %ds
+mov %dx, %es
+mov %dx, %fs
+mov %dx, %gs
 
 mov %esp, %edx
 

kernel/elf.c

@@ -26,13 +26,15 @@ void run_program(uint8_t* code, size_t code_length, uint8_t* data, size_t data_l
 
     struct CPUState target = {
         .eip = (size_t) userland_code,
-        .esp = 0x00401000,
-        .eax = 0,
+        .esp = 0x00400800,
+        .eax = 0x00400800,
         .ebx = 0,
         .ecx = 0,
         .edx = 0,
         .cs = 0x18 | 0x3,
         .ds = 0x20 | 0x3,
+        /// .cs = 0x08,
+        // .ds = 0x10,
         .eflags = 0x0200,
         .ebp = 0,
     };

kernel/kernel.c

@@ -14,7 +14,7 @@
 #endif
 
 uint8_t program[] = {
-    // 0xcd, 0x80, // int $0x80
+    0xcd, 0x80, // int $0x80
     0xb9, 0x02, 0x00, 0x00, 0x00, // mov $0, %ecx
     0xff, 0xe1, // jmp *%ecx
 };
@@ -37,6 +37,8 @@ void kernel_main(void)
     setup_tasks();
     setup_paging();
 
+    terminal_writestring("Woaw\n");
+
     asm("cli");
 
     run_program(program, sizeof(program), data, sizeof(data));
@@ -44,8 +46,12 @@ void kernel_main(void)
     asm("sti");
     asm("int $0x20");
 
+    int i = 0;
     while (true) {
-        terminal_writestring("Hello from Kernelspace 1\n");
-        // terminal_writestring("Hello from Kernelspace 2\n");
+        i += 1;
+        if (i == 1 << 16) {
+            terminal_writestring("Hello\n");
+            i = 0;
+        }
     }
 }

kernel/task.c

@@ -1,6 +1,7 @@
 #include <kernel/task.h>
 #include <kernel/heap.h>
 #include <kernel/tty.h>
+#include <debugging.h>
 
 struct Task* tasks;
 size_t tasks_capacity;
@@ -11,6 +12,8 @@ size_t current_task = 0;
 void setup_tasks()
 {
     tasks = malloc(sizeof(*tasks));
+    tasks[0].state.cs = 8;
+    tasks[0].state.ds = 16;
     tasks_capacity = 1;
     num_tasks = 1;
 }
@@ -82,27 +85,20 @@ static void save_state(
 
     size_t eflags
 ) {
-    struct CPUState state = {
-        .eax = eax,
-        .ebx = ebx,
-        .ecx = ecx,
-        .edx = edx,
+    tasks[current_task].state.eax = eax,
+    tasks[current_task].state.ebx = ebx,
+    tasks[current_task].state.ecx = ecx,
+    tasks[current_task].state.edx = edx,
 
-        .esp = esp,
-        .ebp = ebp,
+    tasks[current_task].state.esp = esp,
+    tasks[current_task].state.ebp = ebp,
 
-        .eip = eip,
+    tasks[current_task].state.eip = eip,
 
-        .esi = esi,
-        .edi = edi,
+    tasks[current_task].state.esi = esi,
+    tasks[current_task].state.edi = edi,
 
-        .cs = cs,
-        .ds = ds,
-
-        .eflags = eflags,
-    };
-    
-    tasks[current_task].state = state;
+    tasks[current_task].state.eflags = eflags,
     
     current_task++;
     current_task %= num_tasks;
@@ -117,8 +113,10 @@ void next_task() {
     cs = s.cs;
     eip = s.eip;
 
+    print_hex_bytes(&tasks[current_task].state.eip, 4);
+    terminal_writestring("\n");
+
     if ((cs & 3) == 0) {
-        // esp -= 4;
         jump_kernel(
             s.edi, 
             s.esi, 
@@ -144,6 +142,11 @@ void next_task() {
 }
 
 void _switch_task(
+    size_t eip_passed,
+    size_t cs_passed,
+    size_t eflags_passed,
+    size_t esp_passed,
+
     size_t edi,
     size_t esi,
     size_t ebp,
@@ -153,14 +156,11 @@ void _switch_task(
     size_t ecx,
     size_t eax,
 
-    size_t eip_passed,
-    size_t cs_passed,
-    size_t eflags_passed,
-    size_t esp_passed,
     size_t ds_passed
 ) 
 {
-    // terminal_writestring("Switching task\n");
+    terminal_writestring("Switching task\n");
+
     if (num_tasks == 0) {
         return;
     };
@@ -168,12 +168,15 @@ void _switch_task(
     size_t ds;
     if ((cs & 3) == 0) {
         ds = 0x10;
-        esp_current = esp_current + sizeof(size_t) * 3;
+        esp_current = esp_passed + sizeof(size_t) * 3;
     } else {
         ds = ds_passed;
         esp_current = esp_passed;
     }
 
+    print_hex_bytes(&eip_passed, 4);
+    terminal_writestring("\n");
+
     save_state(eax, ebx, ecx, edx, esp_current, ebp, esi, edi, eip_passed, cs_passed, ds, eflags_passed);
 
     next_task();