From ad9e577e8b2f6431d48a6a64fd95aff432e48441 Mon Sep 17 00:00:00 2001
From: Christian Cunningham <cc@localhost>
Date: Thu, 10 Mar 2022 20:01:25 -0800
Subject: More Deterministic
---
src/sys/schedule.S | 2 +-
src/sys/schedule.c | 67 ++++++++++++++++++++----------------------------------
2 files changed, 26 insertions(+), 43 deletions(-)
(limited to 'src/sys')
diff --git a/src/sys/schedule.S b/src/sys/schedule.S
index e44d12b..d7301fc 100644
--- a/src/sys/schedule.S
+++ b/src/sys/schedule.S
@@ -35,7 +35,7 @@ cleanup:
mov r1, #0
1:
str r1, [r0, #0]
- // cleanup stack
+ // Free thread in table
svc #3
// usrloop -> rthread
ldr r3, =scheduler
diff --git a/src/sys/schedule.c b/src/sys/schedule.c
index b068963..8c65c6f 100644
--- a/src/sys/schedule.c
+++ b/src/sys/schedule.c
@@ -34,71 +34,54 @@ void init_scheduler(void)
trb += 1;
}
}
- sched_stack_count = 0;
// Initialize nextpid
nextpid = FIRST_AVAIL_PID;
+
+ for (unsigned long i = 0; i < MAX_THREADS; i++) {
+ struct Thread* t = &threads[i];
+ t->offset = i;
+ t->sp_base = 0x20000000 - STACK_SIZE*i;
+ }
}
-struct RStack get_stack(void)
+struct Thread* get_available_thread(void)
{
- struct RStack r = {.sp = 0, .idx = -1};
- // Find an available stack
- for (int i = 0; i < MAX_THREADS; i++) {
- if (stacks_table[i] == 0) {
- // Mark unavailable
- stacks_table[i] = 1;
- r.idx = i;
- r.sp = (void*)0x20000000 - STACK_SIZE*i;
- return r;
- }
+ for(unsigned long i = 0; i < MAX_THREADS; i++) {
+ if (thread_table[i] == 0)
+ return &threads[i];
}
- return r;
+ return 0;
}
void add_thread(void* pc, void* arg, unsigned char priority)
{
- //void* sp = get_stack();
- struct RStack r = get_stack();
- //struct Thread* thread = (struct Thread*)malloca(sizeof(struct Thread), 4);
- struct Thread* thread = (struct Thread*)kmalloc(sizeof(struct Thread));
+ struct Thread* thread = get_available_thread();
+ thread_table[thread->offset] = 1;
thread->pc = pc;
- // Valid stack has been obtained for this thread
- if (r.sp) {
- thread->sp_base = r.idx;
- unsigned long* argp = r.sp;
- argp -= 13;
- *argp = (unsigned long)arg; // Set r0 to the argument
- argp -= 1;
- *(unsigned long**)argp = (unsigned long*)cleanup; // Set lr to the cleanup function
- thread->sp = (void*)argp;
- thread->status = THREAD_READY;
- sched_stack_count++;
- }
- // Couldn't allocate a proper stack
- else {
- thread->sp_base = r.idx;
- thread->sp = r.sp;
- thread->status = THREAD_SERROR;
- }
+ unsigned long* argp = (void*)thread->sp_base;
+ argp -= 13;
+ *argp = (unsigned long)arg; // Set r0 to the argument
+ argp -= 1;
+ *(unsigned long**)argp = (unsigned long*)cleanup; // Set lr to the cleanup function
+ thread->sp = argp;
+ thread->status = THREAD_READY;
thread->mptr = (void*)0;
thread->pid = nextpid++;
// Reset next pid on overflow
if (nextpid < FIRST_AVAIL_PID) {
nextpid = FIRST_AVAIL_PID;
}
- thread->priority = priority % PRIORITIES;
+ if (priority >= PRIORITIES)
+ thread->priority = PRIORITIES - 1;
+ else
+ thread->priority = priority;
thread->old_priority = -1;
thread->preempt = 0;
// Add Thread* to scheduler's appropriate buffer
struct ThreadQueues* tq = &scheduler.thread_queues[thread->priority];
struct ThreadRotBuffer* trb;
// Add to stack error queue if stack was not obtained
- if (thread->status == THREAD_SERROR) {
- trb = &tq->serror;
- }
- else {
- trb = &tq->ready;
- }
+ trb = &tq->ready;
trb->queue[trb->woffset++] = thread;
trb->woffset %= TQUEUE_MAX;
// Schedule if this was called in usermode
--
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