[feat] Desktop render color

include/kernel/scheduler.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <efi.h>
+#include <memory/pmm.h>
+#include <common.h>
+
+#define TASK_STACK_SIZE  (PAGE_SIZE * 4)  // 16 KB kernel stack per task
+#define TASK_MAX         32
+#define TASK_NAME_LEN    32
+#define TIME_SLICE_DEFAULT 5  // 5 ticks = 50ms at 100 Hz
+
+typedef enum {
+    TASK_STATE_READY,
+    TASK_STATE_RUNNING,
+    TASK_STATE_TERMINATED,
+} task_state_t;
+
+typedef struct task {
+    UINT64          rsp;            // saved stack pointer (for context switch)
+    UINT32          id;
+    task_state_t    state;
+    char            name[TASK_NAME_LEN];
+    void*           stack_base;     // base address of kernel stack
+    struct task*    next;           // circular linked list
+    UINT32          time_slice;     // remaining ticks before preemption
+} task_t;
+
+// Create a new task. Returns task pointer or NULL on failure.
+task_t* task_create(const char* name, void (*entry)(void));
+
+// Yield CPU to next ready task (cooperative)
+void yield(void);
+
+// Start the scheduler — does not return. Picks first READY task and runs it.
+void scheduler_run(void);
+
+// Called by a task when it finishes — marks as TERMINATED and yields
+void task_exit(void);
+
+// Get current running task
+task_t* scheduler_current(void);
+
+// Timer tick handler — called by PIT IRQ 0, drives preemption
+void scheduler_tick(void);