1 files changed, 106 insertions, 0 deletions
diff --git a/src/components/grid/node.c b/src/components/grid/node.c
new file mode 100644
index 0000000..0aed768
--- /dev/null
+++ b/src/components/grid/node.c
@@ -0,0 +1,106 @@
+/* very simple grid node with 32bit private region, does not currently signal
+ * being busy or anything. I think I might have to refine the message passing
+ * interface I have, but this is good enough.
+ *
+ * Each node should have a router beneath it, just to simplify my life. A router
+ * is basically a bus with a fallback ascension path.
+ */
+#include <gran/grid/node.h>
+
+struct grid_node {
+	struct component component;
+	uint8_t u, v, x, y;
+	struct component *left, *right, *up, *down, *ascend, *lower;
+};
+
+typedef read_callback callback;
+
+static stat grid_route(struct grid_node *grid, struct packet *pkt, callback op)
+{
+	uint64_t addr = packet_addr(pkt);
+	uint8_t u = (addr >> 56) & 0xff;
+	uint8_t v = (addr >> 48) & 0xff;
+	uint8_t x = (addr >> 40) & 0xff;
+	uint8_t y = (addr >> 32) & 0xff;
+
+	if (grid->u == u && grid->v == v && grid->x == x && grid->y == y)
+		return op(grid->lower, pkt);
+
+	if (grid->u != u || grid->v != v) {
+		if (!grid->ascend)
+			return EBUS;
+
+		return op(grid->ascend, pkt);
+	}
+
+	if (y < grid->y) {
+		if (!grid->down)
+			return EBUS;
+
+		return op(grid->down, pkt);
+	}
+
+	if (y > grid->y) {
+		if (!grid->up)
+			return EBUS;
+
+		return op(grid->up, pkt);
+	}
+
+	if (x < grid->x) {
+		if (!grid->left)
+			return EBUS;
+
+		return op(grid->left, pkt);
+	}
+
+	if (x > grid->x) {
+		if (!grid->right)
+			return EBUS;
+
+		return op(grid->right, pkt);
+	}
+
+	return EBUS;
+}
+
+static stat grid_write(struct grid_node *node, struct packet *pkt)
+{
+	return grid_route(node, pkt, write);
+}
+
+static stat grid_read(struct grid_node *node, struct packet *pkt)
+{
+	return grid_route(node, pkt, read);
+}
+
+struct component *create_grid_node(uint8_t u, uint8_t v, uint8_t x, uint8_t y)
+{
+	struct grid_node *node = calloc(1, sizeof(struct grid_node));
+	if (!node)
+		return NULL;
+
+	node->u = u;
+	node->v = v;
+	node->x = x;
+	node->y = y;
+	node->component.write = (write_callback)grid_write;
+	node->component.read = (read_callback)grid_read;
+
+	return (struct component *)node;
+}
+
+stat grid_node_connect(struct component *node,
+		struct component *left, struct component *right,
+		struct component *up, struct component *down,
+		struct component *lower, struct component *ascend)
+{
+	struct grid_node *n = (struct grid_node *)node;
+	n->left = left;
+	n->right = right;
+	n->up = up;
+	n->down = down;
+	n->lower = lower;
+	n->ascend = ascend;
+	return OK;
+}