Change lru from double to single linked list. Only the font cache uses LRU and it never searches in reverse. Saves 2 bytes per glyph.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30818 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 1 insertions, 11 deletions

diff --git a/firmware/include/lru.h b/firmware/include/lru.h
index cd271afbd8..9bfe0cd4a7 100644
--- a/firmware/include/lru.h
+++ b/firmware/include/lru.h
@@ -33,7 +33,7 @@ struct lru
     void *_base;
 };
 
-#define LRU_SLOT_OVERHEAD (2 * sizeof(short))
+#define LRU_SLOT_OVERHEAD (1 * sizeof(short))
 
 /* Create LRU list with specified size from buf. */
 void lru_create(struct lru* pl, void *buf, short size, short data_size);
diff --git a/firmware/lru.c b/firmware/lru.c
index 798e09fb31..5e1561e492 100644
--- a/firmware/lru.c
+++ b/firmware/lru.c
@@ -48,11 +48,9 @@ void lru_create(struct lru* pl, void *buf, short size, short data_size)
     for (i=0; i<pl->_size; i++)
     {
         lru_node_p(pl, i)->_next = i + 1;
-        lru_node_p(pl, i)->_prev = i - 1;
     }
 
     /* Fix up head and tail to form circular buffer */
-    lru_node_p(pl, 0)->_prev = pl->_tail;
     lru_node_p(pl, pl->_tail)->_next = pl->_head;
 }
 
@@ -92,20 +90,12 @@ void lru_touch(struct lru* pl, short handle)
 
     /* Remove current node from linked list */
     struct lru_node* curr_node = lru_node_p(pl, handle);
-    struct lru_node* prev_node = lru_node_p(pl, curr_node->_prev);
-    struct lru_node* next_node = lru_node_p(pl, curr_node->_next);
-
-    prev_node->_next = curr_node->_next;
-    next_node->_prev = curr_node->_prev;
 
     /* insert current node at tail */
     struct lru_node* tail_node = lru_node_p(pl, pl->_tail);
     short tail_node_next_handle = tail_node->_next; /* Bug fix */
-    struct lru_node* tail_node_next = lru_node_p(pl, tail_node_next_handle); /* Bug fix */
 
     curr_node->_next = tail_node->_next;
-    curr_node->_prev = pl->_tail;
-    tail_node_next->_prev = handle; /* Bug fix */
     tail_node->_next = handle;
 
     pl->_tail = handle;