Task scheduler

task.h

@@ -0,0 +1,56 @@
+#ifndef TASK_H
+#define TASK_H
+
+#include <efi.h>
+#include "boot_info.h"
+
+/* Maximum number of concurrent tasks */
+#define TASK_MAX         32
+
+/* Stack size per task: 32 KB (8 pages) */
+#define TASK_STACK_PAGES 8
+#define TASK_STACK_SIZE  (TASK_STACK_PAGES * 4096)
+
+/* Maximum task name length */
+#define TASK_NAME_LEN    32
+
+/* Task states */
+typedef enum {
+    TASK_STATE_FREE = 0,       /* PCB slot is unused */
+    TASK_STATE_READY,          /* Runnable, waiting for CPU */
+    TASK_STATE_RUNNING,        /* Currently executing on CPU */
+    TASK_STATE_TERMINATED      /* Finished execution */
+} TaskState;
+
+/* Task entry function signature */
+typedef void (*TaskEntryFn)(void *arg);
+
+/* ================================================================
+ *  Process Control Block (PCB)
+ * ================================================================ */
+typedef struct Task {
+    UINT32      pid;                    /* Process ID */
+    TaskState   state;                  /* Current state */
+    CHAR16      name[TASK_NAME_LEN];    /* Human-readable name */
+    UINT64      saved_rsp;              /* Saved stack pointer (context switch) */
+    UINT64      stack_base;             /* Base address of allocated stack */
+    UINTN       stack_pages;            /* Stack size in pages */
+    TaskEntryFn entry;                  /* Entry function pointer */
+    void       *arg;                    /* Argument passed to entry */
+    UINTN       switches;               /* Number of times scheduled */
+} Task;
+
+/* -------- Task API -------- */
+
+void   task_init(BootInfo *Boot);
+Task  *task_create(const CHAR16 *name, TaskEntryFn entry, void *arg);
+void   task_yield(void);
+void   task_exit(void);
+Task  *task_current(void);
+UINTN  task_count(void);
+void   task_print_list(BootInfo *Boot);
+
+/* Assembly context switch (defined in context_switch.S) */
+extern void context_switch(UINT64 *old_rsp, UINT64 new_rsp);
+
+#endif