feat: basic scheduler; basic composer

kernel/inc/core/scheduler.h

@@ -1,4 +1,16 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 // Copyright (c) 2025 0xKarinyash
 
-#pragma once
+#pragma once
+#include <types.h>
+typedef struct task {
+    u64 rsp;
+    struct task* next;
+    u32 id;
+    u32 sleep_ticks;
+} task_t;
+
+void sched_init();
+task_t* sched_spawn(void(*entry)());
+u64 sched_next(u64 curr_rsp);
+void yield(u64 ticks);

kernel/inc/drivers/shitgui.h

@@ -26,6 +26,15 @@ typedef struct {
     const unsigned char* base;
 } SG_Font;
 
+typedef struct {
+    SG_Context *ctx;
+    SG_Point pos;
+    const char *title;
+} SG_Window;
+
+void sg_init(SG_Context *ctx);
 void sg_put_img(SG_Context *ctx, SG_Point *p, SG_Image *img);
 void sg_draw_rect(SG_Context *ctx, SG_Point *p, u32 w, u32 h, u32 color);
 void sg_draw_char_bitmap(SG_Context *ctx, SG_Point *p, char c, u32 color, SG_Font *font);
+SG_Window* create_window(const char *title, SG_Point* size, SG_Point* position);
+void composer_task();

kernel/inc/drivers/timer.h

@@ -5,6 +5,6 @@
 #include <types.h>
 
 void timer_init(u32 freq);
-void timer_handler();
+u64 timer_handler(Registers *regs);
 void sleep(u64 ms);
 u64 get_uptime();

kernel/src/arch/x86_64/interrupts.asm

@@ -70,9 +70,10 @@ global %2
     mov rdi, rsp
     cld 
     call irq_handler_c
+
+    mov rsp, rax
     
     POPALL
-    
     add rsp, 16 
     iretq
 %endmacro

kernel/src/arch/x86_64/interrupts.c

@@ -16,12 +16,14 @@ void isr_handler_c(Registers *regs) {
     panic_exception(regs);
 }
 
-void irq_handler_c(Registers *regs) {
+u64 irq_handler_c(Registers *regs) {
+    u64 curr_rsp = (u64)regs;
     switch (regs->int_no) {
-        case 32: return timer_handler();
-        case 33: return kb_handler();
+        case 32: curr_rsp = timer_handler(regs); break;
+        case 33: kb_handler(); break;
         default: outb(SLAVE_COMMAND, 0x20); break;
     }
 
     outb(MASTER_COMMAND, 0x20);
+    return curr_rsp;
 }

kernel/src/core/scheduler.c

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (c) 2025 0xKarinyash
+
+#include <core/panic.h>
+#include <core/scheduler.h>
+#include <mm/heap.h>
+
+task_t* curr_task = nullptr;
+u32 next_pid = 1;
+
+extern void irq0_handler();
+
+void sched_init() {
+    task_t* kt = (task_t*)malloc(sizeof(task_t));
+
+    kt->id = 0;
+    kt->sleep_ticks = 0;
+    kt->next = kt;
+
+    curr_task = kt;
+}
+
+task_t* sched_spawn(void(*entry)()) {
+    task_t* t = (task_t*)malloc(sizeof(task_t));
+    if (!t) return nullptr;
+    
+    u64 stack_size = 16384;
+    u8* stack_base = (u8*)malloc(stack_size);
+    if (!stack_base) panic("OOM for task stack");
+    u64* rsp = (u64*)(stack_base + stack_size); 
+
+    *--rsp = 0x10; // SS -- Kernel data
+    *--rsp = (u64)stack_base + stack_size; // rsp
+    *--rsp = 0x202; // RFLAGS -- Interrupts Enabled | Reserved bit;
+    *--rsp = 0x08; // CS -- Kernel Code;
+    *--rsp = (u64)entry; // RIP
+
+    *--rsp = 0; // int no
+    *--rsp = 0; // err code
+
+    for (u8 i = 0; i < 15; i++) *--rsp = 0; // R15 .. RAX
+
+    t->rsp = (u64)rsp;
+    t->id = next_pid++;
+    t->sleep_ticks = 0;
+    t->next = curr_task->next;
+    curr_task->next = t;
+
+    return t;
+}
+
+u64 sched_next(u64 curr_rsp) {
+    if (!curr_task) return curr_rsp;
+
+    curr_task->rsp = curr_rsp;
+    task_t* it = curr_task->next;
+
+    do {
+        if (it->sleep_ticks > 0) it->sleep_ticks--;
+        it = it->next;
+    } while (it != curr_task->next);
+
+    if (curr_task->sleep_ticks > 0) curr_task->sleep_ticks--;
+
+    task_t* next = curr_task->next;
+    while (next != curr_task && next->sleep_ticks > 0) next = next->next; // what the fuck i just wrote  
+
+    curr_task = next;
+    return curr_task->rsp;
+}
+
+void yield(u64 ticks) {
+    curr_task->sleep_ticks = ticks;
+    __asm__ volatile("hlt");
+}

kernel/src/core/string.c

@@ -3,7 +3,7 @@
 
 #include <core/string.h>
 
-i32 strcmp(const char* s1, const char* s2) {
+i32 strcmp(const char *s1, const char *s2) {
     while (*s1 && (*s1 == *s2)) {
         s1++;
         s2++;

kernel/src/drivers/shitgui.c

@@ -1,9 +1,22 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 // Copyright (c) 2025 0xKarinyash
 
+#include <core/scheduler.h>
+#include <core/panic.h>
 #include <drivers/shitgui.h>
+#include <mm/heap.h>
+#include <mm/memory.h>
 
 #define SHITGUI_TRANSPARENCY_KEY 0xFF00FF
+#define SHITGUI_MAX_WINDOWS_AMOUNT 64
+
+SG_Context* main_context;
+SG_Window* windows[SHITGUI_MAX_WINDOWS_AMOUNT]; // нет блять линукс
+u64 windows_amount = 0;
+
+void sg_init(SG_Context *ctx) {
+    main_context = ctx;
+}
 
 void sg_put_img(SG_Context *ctx, SG_Point *p, SG_Image *img) {
     if (!ctx->fb || !img) return;
@@ -67,4 +80,64 @@ void sg_draw_char_bitmap(SG_Context *ctx, SG_Point *p, char c, u32 color, SG_Fon
             }
         }
     }
+}
+
+SG_Window* create_window(const char *title, SG_Point* size, SG_Point* position) {
+    if (windows_amount >= SHITGUI_MAX_WINDOWS_AMOUNT) return nullptr; 
+    SG_Context* ctx = nullptr;
+    u32* fb = nullptr;
+    SG_Window* window = nullptr;
+
+    ctx = (SG_Context*)malloc(sizeof(SG_Context));
+    if (!ctx) goto fail; // goto is GOOD for cleaning up in C stfu. 
+                         // Mainline linux kernel contains 100k gotos
+
+    fb = malloc(size->x * size->y * sizeof(u32));
+    if (!fb) goto fail;
+    memset(fb, 0, size->x * size->y * sizeof(u32));
+
+    window = (SG_Window*)malloc(sizeof(SG_Window));
+    if (!window) goto fail;
+
+    ctx->fb = fb;
+    ctx->height = size->y;
+    ctx->width = size->x;
+    ctx->pitch = size->x;
+    
+    
+    window->ctx = ctx;
+    window->title = title;
+    window->pos.x = position->x;
+    window->pos.y = position->y;
+
+    windows[windows_amount] = window;
+    windows_amount++;    
+
+    return window;
+
+fail:
+    if (ctx) free(ctx);
+    if (fb) free(fb);
+    if (window) free(window);
+
+    return nullptr;
+}
+
+void render_window(SG_Context *ctx, SG_Window *window) {
+    SG_Image img = {0};
+    img.buffer = window->ctx->fb;
+    if (!img.buffer) panic("No img buffer found");
+    img.height = window->ctx->height;
+    img.width  = window->ctx->width;
+
+    sg_put_img(ctx, &window->pos, &img);
+}
+
+void composer_task() {
+    while (true) {
+        for (u64 i = 0; i < windows_amount; i++) {
+            render_window(main_context, windows[i]);
+        }
+        yield(1);
+    }
 }

kernel/src/drivers/timer.c

@@ -4,6 +4,7 @@
 #include <drivers/timer.h>
 #include <io.h>
 #include <types.h>
+#include <core/scheduler.h>
 
 #define PIT_BASE_CLOCK 1193180
 #define PIT_CMD  0x43
@@ -23,9 +24,10 @@ void timer_init(u32 freq) {
     outb(0x21, mask);
 }
 
-void timer_handler() {
+u64 timer_handler(Registers *regs) {
     ticks++;
     outb(MASTER_COMMAND, 0x20);
+    return sched_next((u64)regs);
 }
 
 void sleep(u64 ms) {

kernel/src/kmain.c

@@ -2,6 +2,7 @@
 // Copyright (c) 2025 0xKarinyash
 
 #include "bootinfo.h"
+#include "core/scheduler.h"
 #include <shell/ksh.h>
 
 #include <types.h>
@@ -48,6 +49,10 @@ void kmain(Bootinfo* info) {
     kprintf("Timer initialized\n");
     heap_init();
     kprintf("Heap initialized\n");
+    sched_init();
+    kprintf("Scheduler initialized\n");
+    sg_init(&sg_ctx);
+    kprintf("Shitgui initialized");
 
     info = (Bootinfo*)PHYS_TO_HHDM((u64)info);
 
@@ -65,8 +70,10 @@ void kmain(Bootinfo* info) {
 
     show_splash(&sg_ctx);
 
-    ksh();
-    
-    panic("Kernel main loop exited");
+    sched_spawn(composer_task);
+    sched_spawn(ksh);
+    __asm__ volatile("sti");
     
+    while (true) __asm__ volatile("hlt");
+    panic("How in the name of God you got here?");
 }

kernel/src/mm/heap.c

@@ -8,7 +8,7 @@
 #include <core/panic.h>
 #include <types.h>
 
-#define HEAP_SIZE_PAGES 32
+#define HEAP_SIZE_PAGES 1024
 
 extern u64* pml4_kernel;
 static block_header* heap_list_head = nullptr;

kernel/src/shell/dbgcmd.c

@@ -3,18 +3,65 @@
 // contents of this file will be changed CONSTANTLY
 // im just testing new stuff here
 
+#include "core/panic.h"
+#include "drivers/shitgui.h"
 #include <drivers/timer.h>
 #include <drivers/console.h>
 #include <types.h>
 #include <shell/dbgcmd.h>
 
+#include <core/scheduler.h>
+
+SG_Window* win_a = nullptr;
+SG_Window* win_b = nullptr;
+
+void a() {
+    SG_Point sizes = {0};
+    sizes.x = win_a->ctx->width;
+    sizes.y = win_a->ctx->height;
+
+    u64 t = 0;
+    while (true) {
+        for (u32 y = 0; y < sizes.y; y++) {
+            for (u32 x = 0; x < sizes.x; x++) {
+                win_a->ctx->fb[y * sizes.x + x] = (x * y) ^ t;
+            }
+        }
+        t++;
+    }
+}
+void b() {
+    SG_Point sizes = {0};
+    sizes.x = win_b->ctx->width;
+    sizes.y = win_b->ctx->height;
+
+    u64 t = 0;
+    while (true) {
+        for (u32 y = 0; y < sizes.y; y++) {
+            for (u32 x = 0; x < sizes.x; x++) {
+                win_b->ctx->fb[y * sizes.x + x] = (x ^ y) ^ t;
+            }
+        }
+        t++;
+    }
+}
+
 u64 debug() {
-    kprintf("Float test\n");
-    kprintf("Trying 3.14 + 1.44 in 3 seconds..\n");
-    sleep(3000);
-    volatile float a = 3.14;
-    volatile float b = 1.44;
-    volatile float c = a + b;
-    kprintf("%d", (i32)c);
+    kprintf("scheduler test\n");
+    SG_Point sizes = {0};
+    sizes.x = 256;
+    sizes.y = 256;
+    SG_Point pos_a = {0};
+    pos_a.x = 100;
+    pos_a.y = 40;
+    SG_Point pos_b = {0};
+    pos_b.x = 512;
+    pos_b.y = 40;
+    win_a = create_window("A", &sizes, &pos_a);
+    if (!win_a) panic("No win a");
+    win_b = create_window("B", &sizes, &pos_b);
+    if (!win_b) panic("No win b");
+    sched_spawn(a);
+    sched_spawn(b);
     return 0;
 }