Fix: lab3 on-board problems

kernel/lib/ringbuffer.c

@@ -24,11 +24,11 @@ int ringbuffer_push(ringbuffer_t *buf, uint8_t val)
     return ERR_OUT_OF_BOUND;
 
   *buf->write++ = val;
-  ++buf->size;
 
   if (buf->write == buf->data + buf->cap)
     buf->write = buf->data;
 
+  ++buf->size;
   return NO_ERROR;
 }
 
@@ -38,10 +38,18 @@ uint8_t ringbuffer_bump(ringbuffer_t *buf)
     exit(ERR_INVALID_OP);
 
   uint8_t ret = *buf->read++;
-  --buf->size;
 
   if (buf->read == buf->data + buf->cap)
     buf->read = buf->data;
 
+  --buf->size;
   return ret;
 }
+
+uint8_t ringbuffer_peek(ringbuffer_t *buf)
+{
+  if (buf->size == 0)
+    exit(ERR_INVALID_OP);
+
+  return *buf->read;
+}

kernel/lib/shell.c

@@ -159,20 +159,41 @@ void _reboot(void)
   _reset(1 << 16);
 }
 
+char *_shell_buf = (char *)0x0;
+int _shell_sz = 0;
+
+static inline
+int _shell_operations(char ch)
+{
+  switch (ch) {
+  case 0x7f:
+    if (_shell_sz > 0) {
+      --_shell_sz;
+      uart_puts("\b \b");
+    }
+    return true;
+  default:
+  }
+  return false;
+}
+
 int shell(file_node_t *initrd_root)
 {
   uart_puts("# ");
-  char *buf = kmalloc(INPUT_BUFLEN * sizeof(char)), ch;
-  int sz = 0;
+  char ch;
+  _shell_buf = kmalloc(INPUT_BUFLEN * sizeof(char));
+  _shell_sz = 0;
   while ((ch = uart_getc()) != '\n') {
-    buf[sz++] = ch;
+    if (_shell_operations(ch))
+      continue;
+    _shell_buf[_shell_sz++] = ch;
     uart_putb((const uint8_t *)&ch, 1);
   }
   uart_puts(ENDL);
-  buf[sz] = ' ';
+  _shell_buf[_shell_sz] = ' ';
 
   vector_t *args = make_vector(0);
-  for (char *saveptr = 0x0, *tok = strtok_r(buf, " ", &saveptr);
+  for (char *saveptr = 0x0, *tok = strtok_r(_shell_buf, " ", &saveptr);
        tok; tok = strtok_r((char *)0x0, " ", &saveptr)) {
     VEC_PUSH(args, tok);
     LOG(tok);

kernel/lib/timer.c

@@ -61,6 +61,16 @@ void _set_timer_interrrupt()
   }
 }
 
+static inline
+void _traverse(timer_t *t)
+{
+  if (!t) return;
+  DEBUG_EXCEP(t->data.firing_tick);
+  t->data.func(t->data.param);
+  _traverse(t->_l);
+  _traverse(t->_r);
+}
+
 void add_task(task_t task)
 {
   DEBUG_EXCEP("add task");
@@ -74,6 +84,8 @@ void add_task(task_t task)
   };
 
   global_timer = _merge(global_timer, newtimer);
+
+  _traverse(global_timer);
   _set_timer_interrrupt();
 }
 

kernel/lib/uart.c

@@ -162,6 +162,7 @@ size_t uart_getb_async(uint8_t *bytes, size_t len)
   for (; recvlen < len; ++bytes, ++recvlen) {
     while (!uart_readbuf->size)
       wfe(); // wait for interrupt
+  
     *bytes = ringbuffer_bump(uart_readbuf);
   }