Rewrote scheduler in Assembly

1 files changed, 80 insertions, 40 deletions

diff --git a/src/sys/schedule.c b/src/sys/schedule.c
index 1bb02c2..4b071c3 100644
--- a/src/sys/schedule.c
+++ b/src/sys/schedule.c
@@ -1,3 +1,4 @@
+#include <cpu/irq.h>
 #include <drivers/uart.h>
 #include <sys/core.h>
 #include <sys/schedule.h>
@@ -15,6 +16,12 @@ struct Scheduler scheduler = {
 	},
 	.rthread_ll = 0,
 };
+unsigned long syssp = 0;
+struct cpu_context syscpu = {
+	.r4 = 0, .r5 = 0, .r6 = 0, .r7 = 0,
+	.r8 = 0, .r9 = 0, .r10 = 0, .r11 = 0,
+	.r12 = 0, .lr = 0,
+};
 
 void init_scheduler(void)
 {
@@ -24,6 +31,7 @@ void init_scheduler(void)
 		scheduler.tlist[i].data = 0;
 	}
 	scheduler.rthread_ll = 0;
+	scheduler.ctx = &syscpu;
 }
 
 unsigned char stacks_table[MAX_THREADS] = {0, };
@@ -42,12 +50,12 @@ void* get_stack(void)
 static unsigned long nextpid = 3;
 void add_thread(void (*thread_fxn)(void), unsigned char priority)
 {
-	struct Thread* thread = (struct Thread*)malloc(sizeof(struct Thread));
+	struct Thread* thread = (struct Thread*)malloca(sizeof(struct Thread), 4);
 	// Set the program counter to the entry
 	thread->thread = thread_fxn;
 	// Get a stack frame
-	thread->stack = get_stack();
-	thread->stack_base = thread->stack;
+	thread->stack_base = get_stack();
+	thread->stack = thread->stack_base;
 	// Put in error state for no stack
 	if(thread->stack == 0)
 		thread->data.status = THREAD_STACK_ERROR;
@@ -57,6 +65,8 @@ void add_thread(void (*thread_fxn)(void), unsigned char priority)
 	thread->data.mutex_waiting = 0;
 	// Set PID
 	thread->data.pid = nextpid++;
+	thread->data.preempt_count = 0;
+	thread->data.cpu_context.lr = (unsigned long)cleanup;
 	unsigned char p = priority;
 	if (p >= PRIORITIES) {
 		p = PRIORITIES - 1;
@@ -81,70 +91,100 @@ struct LL* get_next_thread(void)
 	return 0;
 }
 
-unsigned long syssp = 0;
-void schedule(void)
+void schedule_c(void)
 {
-	// Preserve current process's registers
-	//  in the current stack
-	asm volatile ("push {r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, lr}");
+	// Preserve registers in current context
+	preserve_ctx(scheduler.ctx);
+
 	// Get current thread
 	struct LL* current_thread_ll = scheduler.rthread_ll;
 	// Get next thread
 	struct LL* next_thread_ll = get_next_thread();
 
 	// If there is a current thread
-	if (current_thread_ll) {
+	if (current_thread_ll != 0) {
 		// If we are switching the thread
 		if (current_thread_ll != next_thread_ll) {
 			// Context switch
 			struct Thread* current_thread = current_thread_ll->data;
 			struct Thread* next_thread = next_thread_ll->data;
-			preservestack(current_thread);
-			preservepc(current_thread);
-			restorestack(next_thread);
-			//restoreregs(next_thread);
+			preserve_stack(current_thread);
+			//preserve_pc(current_thread);
+			current_thread->thread = (void*)current_thread->data.cpu_context.lr;
+			restore_stack(next_thread);
 			scheduler.rthread_ll = next_thread_ll;
+			scheduler.ctx = &next_thread->data.cpu_context;
 		}
 	}
-	else if (next_thread_ll) {
+	else if (next_thread_ll != 0) {
 		struct Thread* next_thread = next_thread_ll->data;
-		preservesysstack(&syssp);
-		//preservesysregs(&regloc)
-		restorestack(next_thread);
-		//restoreregs(next_thread);
+		preserve_sys_stack(&syssp);
+		restore_stack(next_thread);
 		scheduler.rthread_ll = next_thread_ll;
+		scheduler.ctx = &next_thread->data.cpu_context;
 	}
 	if (scheduler.rthread_ll) {
 		struct Thread* rthread = scheduler.rthread_ll->data;
-		// Restore process's registers
-		asm volatile ("pop {r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, lr}");
-		// Run the thread - i.e. jump to the pc
-		asm volatile ("blx lr");
-		//rthread->thread();
-		// Remove the currently running thread after completion
-		remove_running_thread();
-		// Schedule the next thread
-		schedule();
+		restore_ctx(scheduler.ctx);
+		asm volatile ("bx %0" :: "r"(rthread->thread));
 	} else {
-		//restoresysregs(&regloc);
-		restoresysstack(&syssp);
+		scheduler.ctx = &syscpu;
+		restore_sys_stack(&syssp);
+		restore_ctx(scheduler.ctx);
 	}
 }
 
-void remove_running_thread(void)
+void cleanup(void)
 {
 	if (scheduler.rthread_ll != 0) {
+		// Mark the thread as finished
+		struct Thread* t = scheduler.rthread_ll->data;
+		uart_string("Cleaning up thread ");
+		uart_10(t->data.pid);
+		uart_char('\n');
+		t->data.status = THREAD_FINISHED;
+		// Mark the stack space as free
+		unsigned long sidx = (unsigned long)(heap_end() - t->stack_base)/STACK_SIZE;
+		stacks_table[sidx] = 0;
+		// Remove the thread
 		struct LL* ll = scheduler.rthread_ll;
-		if ((ll->next == ll->prev) && (ll->next == ll)) {
-			ll->data = 0;
-		}
-		else {
-			struct LL* prev = ll->prev;
-			struct LL* next = ll->next;
-			prev->next = ll->next;
-			next->prev = ll->prev;
-			free(ll);
-		}
+		struct LL* prev = ll->prev;
+		struct LL* next = ll->next;
+		prev->next = ll->next;
+		next->prev = ll->prev;
+		free(ll);
 		scheduler.rthread_ll = 0;
 	}
+	// Schedule next thread
+	//uart_string("Scheduling from cleanup!\n");
+	//sched_info();
+	//schedule();
+	schedule();
+}
+
+void sched_info(void)
+{
+	disableirq();
+	uart_string("Scheduler Information\n");
+	for(unsigned long i = 0; i < PRIORITIES; i++) {
+		struct LL* ll = scheduler.tlist[i].next;
+		uart_string("Queue ");
+		uart_10(i);
+		while (ll != &scheduler.tlist[i]) {
+			uart_string("\nThread ");
+			struct Thread* t = ll->data;
+			uart_hex((unsigned long)t->thread);uart_char(' ');
+			uart_hex((unsigned long)t->stack);uart_char(' ');
+			uart_hex((unsigned long)t->stack_base);uart_char(' ');
+			uart_10(t->data.priority);uart_char(' ');
+			uart_10(t->data.preempt_count);uart_char(' ');
+			uart_10(t->data.status);uart_char(' ');
+			uart_hex((unsigned long)t->data.mutex_waiting);uart_char(' ');
+			uart_10(t->data.pid);uart_char('\n');
+			memshow32((unsigned long*)&t->data.cpu_context, 10);
+			ll = ll->next;
+		}
+		uart_char('\n');
+	}
+	enableirq();
 }