minor routing improvement

autotest.c

@@ -103,25 +103,6 @@ fail:
 	return rc;
 }
 
-int fpga_switch_to_yx(struct switch_to_yx* p)
-{
-	struct sw_conns conns = { .model = p->model, .y = p->y, .x = p->x,
-		.start_switch = p->start_switch };
-	while (fpga_switch_conns(&conns) != NO_CONN) {
-		if (is_atyx(p->yx_req, p->model, conns.dest_y, conns.dest_x)) {
-			memcpy(p->chain, conns.chain.chain,
-				conns.chain.chain_size*sizeof(*p->chain));
-			p->chain_size = conns.chain.chain_size;
-			p->dest_y = conns.dest_y;
-			p->dest_x = conns.dest_x;
-			p->dest_connpt = conns.dest_str_i;
-			return 0;
-		}
-	}
-	p->chain_size = 0;
-	return 0;
-}
-
 int main(int argc, char** argv)
 {
 	struct fpga_model model;
@@ -189,6 +170,7 @@ int main(int argc, char** argv)
 	printf("P46 I pinw %s\n", strarray_lookup(&model.str, P46_dev->iob.pinw_out_I));
 
 	switch_to.yx_req = YX_DEV_ILOGIC;
+	switch_to.flags = SWTO_YX_DEF;
 	switch_to.model = &model;
 	switch_to.y = P46_y;
 	switch_to.x = P46_x;
@@ -198,6 +180,7 @@ int main(int argc, char** argv)
 	printf("%s\n", fmt_swchain(&model, switch_to.y, switch_to.x, switch_to.chain, switch_to.chain_size));
 
 	switch_to.yx_req = YX_ROUTING_TILE;
+	switch_to.flags = SWTO_YX_DEF;
 	switch_to.y = switch_to.dest_y;
 	switch_to.x = switch_to.dest_x;
 	switch_to.start_switch = switch_to.dest_connpt;
@@ -206,6 +189,7 @@ int main(int argc, char** argv)
 	printf("%s\n", fmt_swchain(&model, switch_to.y, switch_to.x, switch_to.chain, switch_to.chain_size));
 
 	switch_to.yx_req = YX_ROUTING_TO_FABLOGIC;
+	switch_to.flags = SWTO_YX_CLOSEST;
 	switch_to.y = switch_to.dest_y;
 	switch_to.x = switch_to.dest_x;
 	switch_to.start_switch = switch_to.dest_connpt;
@@ -213,8 +197,7 @@ int main(int argc, char** argv)
 	if (rc) FAIL(rc);
 	printf("%s\n", fmt_swchain(&model, switch_to.y, switch_to.x, switch_to.chain, switch_to.chain_size));
 
-	// todo: result is NN2 but NR1 would be closer
-	// printf_swconns(&model, P46_y, P46_x, P46_dev->iob.pinw_out_I);
+	// next: YX_DEV_LOGIC
 
 	printf("P48 O pinw %s\n", strarray_lookup(&model.str, P48_dev->iob.pinw_in_O));
 

control.c

@@ -619,3 +619,51 @@ void printf_swconns(struct fpga_model* model, int y, int x, str16_t sw)
 			strarray_lookup(&model->str, conns.dest_str_i));
 	}
 }
+
+int fpga_switch_to_yx(struct switch_to_yx* p)
+{
+	struct sw_conns conns = { .model = p->model, .y = p->y, .x = p->x,
+		.start_switch = p->start_switch };
+
+	int best_y, best_x, best_chain_size, best_distance, distance;
+	int best_num_dests;
+	str16_t best_connpt;
+	swidx_t best_chain[MAX_SW_CHAIN_SIZE];
+
+	best_y = -1;
+	while (fpga_switch_conns(&conns) != NO_CONN) {
+		if (is_atyx(p->yx_req, p->model, conns.dest_y, conns.dest_x)) {
+			if (best_y != -1) {
+				distance = abs(conns.dest_y-p->y)
+					+abs(conns.dest_x-p->x);
+				if (distance > best_distance)
+					continue;
+				else if (conns.num_dests > best_num_dests)
+					continue;
+				else if (conns.chain.chain_size > best_chain_size)
+					continue;
+			}
+			memcpy(best_chain, conns.chain.chain,
+				conns.chain.chain_size*sizeof(*best_chain));
+			best_chain_size = conns.chain.chain_size;
+			best_y = conns.dest_y;
+			best_x = conns.dest_x;
+			best_num_dests = conns.num_dests;
+			best_connpt = conns.dest_str_i;
+			best_distance = abs(conns.dest_y-p->y)
+				+abs(conns.dest_x-p->x);
+			if (!p->flags & SWTO_YX_CLOSEST)
+				break;
+		}
+	}
+	if (best_y == -1)
+		p->chain_size = 0;
+	else {
+		memcpy(p->chain, best_chain, best_chain_size*sizeof(*p->chain));
+		p->chain_size = best_chain_size;
+		p->dest_y = best_y;
+		p->dest_x = best_x;
+		p->dest_connpt = best_connpt;
+	}
+	return 0;
+}

control.h

@@ -41,6 +41,7 @@ void fpga_conn_dest(struct fpga_model* model, int y, int x,
 	int connpt_dest_idx, int* dest_y, int* dest_x, str16_t* str_i);
 
 typedef int swidx_t; // swidx_t is an index into the uint32_t switches array
+#define MAX_SW_CHAIN_SIZE 32 // largest seen so far was 10
 
 // returns a switch index, or -1 (NO_SWITCH) if no switch was found
 swidx_t fpga_switch_first(struct fpga_model* model, int y, int x,
@@ -68,8 +69,6 @@ const char* fmt_sw(struct fpga_model* model, int y, int x,
 const char* fmt_swchain(struct fpga_model* model, int y, int x,
 	swidx_t* sw, int sw_size);
 
-#define MAX_SW_CHAIN_SIZE 32 // largest seen so far was 10
-
 struct sw_chain
 {
 	// start and recurring values:
@@ -118,10 +117,14 @@ int fpga_switch_conns(struct sw_conns* conns);
 
 void printf_swconns(struct fpga_model* model, int y, int x, str16_t sw);
 
+#define SWTO_YX_DEF		0
+#define SWTO_YX_CLOSEST		0x0001
+
 struct switch_to_yx
 {
 	// input:
 	int yx_req; // YX_-value
+	int flags; // SWTO_YX-value
 	struct fpga_model* model;
 	int y;
 	int x;