Try to squeeze out a little more performance

``Common wisdom'' dictates that placements are often better than stack
moves, so we bias the generated move list in this fashion. Seems to be
a little faster.

1 files changed, 28 insertions, 3 deletions

diff --git a/include/actions.c b/include/actions.c
index 800a2d4..316b19f 100644
--- a/include/actions.c
+++ b/include/actions.c
@@ -31,6 +31,11 @@ list_append(action_list_t *list, const enum A_TYPE type,
 						const uint8_t data1);
 
 static inline void
+list_prepend(action_list_t *list, const enum A_TYPE type,
+						 const int8_t loc, const uint8_t data0,
+						 const uint8_t data1);
+
+static inline void
 inline_next_ply(void);
 
 static inline void
@@ -82,6 +87,8 @@ void action_list_init(void) {
 	move_deltas[3] = +1;
 }
 
+// We bias place over move by prepending place actions and appending
+// move actions to the generated list
 action_list_t *action_list_generate(void) {
 	action_list_t *list = malloc(sizeof(struct action_list_s));
 
@@ -198,12 +205,12 @@ action_list_t *action_list_generate(void) {
 			else if (material) {
 				// Empty square, generate placements
 				if (flat) {
-					list_append(list, A_PLACE, loc, STONE_FLAT, 0);
+					list_prepend(list, A_PLACE, loc, STONE_FLAT, 0);
 					if (standing)
-						list_append(list, A_PLACE, loc, STONE_STANDING,0);
+						list_prepend(list, A_PLACE, loc, STONE_STANDING,0);
 				}
 				if (cap)
-					list_append(list, A_PLACE, loc, STONE_CAPSTONE, 0);
+					list_prepend(list, A_PLACE, loc, STONE_CAPSTONE, 0);
 			}
 		}
 	}
@@ -397,6 +404,24 @@ list_append(action_list_t *list, const enum A_TYPE type,
 }
 
 static inline void
+list_prepend(action_list_t *list, const enum A_TYPE type,
+						 const int8_t loc, const uint8_t data0,
+						 const uint8_t data1) {
+	action_node_t *new = malloc(sizeof(action_list_t));
+	// TODO: trap errno
+
+	new->next = list->head;
+	list->head = new;
+	new->action = A_BUILD(type, loc, data0, data1);
+
+	if (list->length == 0) {
+		list->tail = new;
+	}
+
+	list->length++;
+}
+
+static inline void
 inline_next_ply(void) {
 	ply++;
 	if (ply == 2) {