build: make without warnings

include/peripherals/timer.h

@@ -8,13 +8,13 @@
 
 #define CLOCKHZ 1000000     // Free-running system timer, constant 1MHz rate
 
-#define TIMER_CS        (PERIPHERALS_BASE + 0x00003000)
-#define TIMER_CLO       (PERIPHERALS_BASE + 0x00003004)
-#define TIMER_CHI       (PERIPHERALS_BASE + 0x00003008)
-#define TIMER_C0        (PERIPHERALS_BASE + 0x0000300C)
-#define TIMER_C1        (PERIPHERALS_BASE + 0x00003010)
-#define TIMER_C2        (PERIPHERALS_BASE + 0x00003014)
-#define TIMER_C3        (PERIPHERALS_BASE + 0x00003018)
+#define TIMER_CS        (unsigned long)(PERIPHERALS_BASE + 0x00003000)
+#define TIMER_CLO       (unsigned long)(PERIPHERALS_BASE + 0x00003004)
+#define TIMER_CHI       (unsigned long)(PERIPHERALS_BASE + 0x00003008)
+#define TIMER_C0        (unsigned long)(PERIPHERALS_BASE + 0x0000300C)
+#define TIMER_C1        (unsigned long)(PERIPHERALS_BASE + 0x00003010)
+#define TIMER_C2        (unsigned long)(PERIPHERALS_BASE + 0x00003014)
+#define TIMER_C3        (unsigned long)(PERIPHERALS_BASE + 0x00003018)
 
 #define TIMER_CS_M0 (1 << 0)
 #define TIMER_CS_M1 (1 << 1)

include/sched.h

@@ -27,7 +27,6 @@ extern struct task_struct *current;
 extern int num_tasks;
 
 typedef struct mem_block MemBlock_t;
-typedef void (*EntryPoint_t)(void);
 
 /* TaskState_t
  *
@@ -90,7 +89,6 @@ struct task_struct
     struct task_struct *parent;    /* A pointer to the TaskDescriptor of the task that created it, its parent */
     struct task_struct *next_task_ready_queue;  /* Pointer to TaskDescriptor of the next ready task (schedule) */
     struct task_struct *next_task_send_queue;   /* Pointer to TaskDescriptor of the next ready task (send queue) */
-    // EntryPoint_t code;              /* Pointer to the instruction memory for this task */
     // MemBlock_t *mem;
 };
 

include/task.h

@@ -3,7 +3,7 @@
 
 #include "sched.h"
 
-int task_create(int priority, EntryPoint_t code);
+int task_create(int priority, void (*task_code)(void));
 int task_parent_tid(void);
 void task_yield(void);
 void task_exit(void);

src/main.c

@@ -11,22 +11,28 @@
 
 void task1()
 {
-    int tid = sys_mytid();
-    uart_printf(CONSOLE, "current: %d\r\n", tid);
-    for (int i = 0; i < 5; i++) {
-        uart_printf(CONSOLE, "Task 1...\r\n");
+    while(1) {
+        int tid = sys_mytid();
+        uart_printf(CONSOLE, "current: %d\r\n", tid);
+        for (int i = 0; i < 5; i++) {
+            uart_printf(CONSOLE, "Task 1...\r\n");
+        }
     }
 }
 
-void task2(unsigned char *array)
+// void task2(unsigned char *array)
+void task2(void)
 {
-    int tid = sys_mytid();
-    uart_printf(CONSOLE, "current: %d\r\n", tid);
-    for (int i = 0; i < 5; i++) {
-        uart_putc(CONSOLE, array[i]);
+    while(1) {
+        int tid = sys_mytid();
+        uart_printf(CONSOLE, "current: %d\r\n", tid);
+        for (int i = 0; i < 5; i++) {
+            // uart_putc(CONSOLE, array[i]);
+            uart_putc(CONSOLE, i);
+        }
+        uart_putc(CONSOLE, '\r');
+        uart_putc(CONSOLE, '\n');
     }
-    uart_putc(CONSOLE, '\r');
-    uart_putc(CONSOLE, '\n');
 }
 
 void task3()
@@ -112,6 +118,8 @@ int kmain(void)
         uart_printf(CONSOLE, "[error] Couldn't create a new task: %d\r\n", ret);
     }
 
+    schedule();
+
 #ifdef DEBUG
     // print_priority_queue();
     int tid = sys_mytid();

src/mm.c

@@ -4,7 +4,7 @@
 
 // static MemBlock_t stacks[BLOCK_COUNT];
 
-static unsigned short mem_map[BLOCK_COUNT];
+// static unsigned short mem_map[BLOCK_COUNT];
 
 // void mem_init(void)
 // {

src/sched.c

@@ -95,6 +95,17 @@ void switch_to(struct task_struct *next)
     cpu_switch_to(prev, next);
 }
 
+// void cpu_switch_to_in_c(struct task_struct *prev, struct task_struct *next)
+// {
+//     /* Save registers from `prev` task */
+//     save_sp(prev->cpu_context.sp);
+//     save_pc(prev->cpu_context.pc);
+
+//     /* Load registers from `next` task */
+//     load_sp(next->cpu_context.sp);
+//     load_pc(next->cpu_context.pc);
+// }
+
 // void switch_to_new_task(void)
 // {
 //     // task_descriptor queues[PRIORITY_LEVELS][16];

src/task.c

@@ -2,6 +2,7 @@
 
 #include "mm.h"
 #include "sched.h"
+#include "sys.h"
 
 /* task_create
  *
@@ -17,7 +18,7 @@
  *      -1  - invalid priority
  *      -2  - kernel is out of task descriptors
  */
-int task_create(int priority, EntryPoint_t code)
+int task_create(int priority, void (*task_code)(void))
 {
     /* Check that the priority is valid */
     if (priority < 0 || priority >= PRIORITY_LEVELS) {
@@ -30,13 +31,26 @@ int task_create(int priority, EntryPoint_t code)
         return -2;  // No available task descriptors
     }
 
+    /* Set the initial values for the CPU context of the task */
+    new_task->cpu_context.x19 = 0;
+    new_task->cpu_context.x20 = 0;
+    new_task->cpu_context.x21 = 0;
+    new_task->cpu_context.x22 = 0;
+    new_task->cpu_context.x23 = 0;
+    new_task->cpu_context.x24 = 0;
+    new_task->cpu_context.x25 = 0;
+    new_task->cpu_context.x26 = 0;
+    new_task->cpu_context.x27 = 0;
+    new_task->cpu_context.x28 = 0;
+    // new_task->cpu_context.sp = GET_STACK_FOR_THIS_INSTRUCTION;   // TODO
+    new_task->cpu_context.x19 = (unsigned long)task_code;
+
     new_task->tid = get_new_tid();
     new_task->priority = priority;
     new_task->parent = get_current_task();
     new_task->state = READY;
     new_task->next_task_ready_queue = NULL;
     new_task->next_task_send_queue = NULL;
-    // new_task->code = code;
     // new_task->mem = get_mem_by_tid(new_task->tid);
 
     /* Add new task into ready_queue */

src/utils.S

@@ -41,11 +41,11 @@ cpu_switch_to:
 	stp	x23, x24, [x8], #16
 	stp	x25, x26, [x8], #16
 	stp	x27, x28, [x8], #16
-	stp	x29, x9, [x8], #16
-	str	x30, [x8]
+	stp	x29, x9, [x8], #16      // TODO(roemvaar): make sure that x29 is fp, sp, and pc
+	str	x30, [x8]               // TODO(roemvaar): check why indirect sp move
     add	x8, x1, x10
 	ldp	x19, x20, [x8], #16		// restore callee-saved registers
-	ldp	x21, x22, [x8], #16
+	ldp	x21, x22, [x8], #16     // TODO(roemvaar): make sure the syntax is okay (address)
 	ldp	x23, x24, [x8], #16
 	ldp	x25, x26, [x8], #16
 	ldp	x27, x28, [x8], #16