From: matt venn <matt@mattvenn.net>
Date: Wed, 22 Apr 2020 15:54:39 +0000 (+0200)
Subject: change order of statements and make gender neutral
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9d69f8a518c16adeeaa8e88d2a84e185716eb2f4;p=SymbiYosys.git

change order of statements and make gender neutral
---

diff --git a/docs/examples/puzzles/wolf_goat_cabbage.sv b/docs/examples/puzzles/wolf_goat_cabbage.sv
index 9c9fe7a..6821098 100644
--- a/docs/examples/puzzles/wolf_goat_cabbage.sv
+++ b/docs/examples/puzzles/wolf_goat_cabbage.sv
@@ -1,38 +1,39 @@
-// A man needs to cross a river with a wolf, a goat and a cabbage. His boat is only large
-// enough to carry himself and one of his three possessions, so he must transport these
-// items one at a time. However, if he leaves the wolf and the goat together unattended,
-// then the wolf will eat the goat; similarly, if he leaves the goat and the cabbage together
-// unattended, then the goat will eat the cabbage. How can the man get across safely with
-// his three items?
+// A person needs to cross a river with a wolf, a goat and a cabbage. Their boat is only large
+// enough to carry themselves and one of their three possessions, so they must transport these
+// items one at a time. However, if they leave the wolf and the goat together unattended,
+// then the wolf will eat the goat; similarly, if they leave the goat and the cabbage together
+// unattended, then the goat will eat the cabbage. How can the person get across safely with
+// their three items?
 
 module wolf_goat_cabbage (input clk, input w, g, c);
 	// everyone starts at the 1st river bank
 	reg bank_w = 0; // wolf
 	reg bank_g = 0; // goat
 	reg bank_c = 0; // cabbage
-	reg bank_m = 0; // man
+	reg bank_person = 0; // person who drives the boat
 
 	always @(posedge clk) begin
+		// person travels and takes the selected item with him
+		if (w && (bank_w == bank_person)) bank_w <= !bank_person;
+		if (g && (bank_g == bank_person)) bank_g <= !bank_person;
+		if (c && (bank_c == bank_person)) bank_c <= !bank_person;
+		bank_person <= !bank_person;
+
 		// maximum one of the control signals must be high
 		assume (w+g+c <= 1);
 
 		// we want wolf, goat, and cabbage on the 2nd river bank
-		cover (bank_w && bank_g && bank_c);
+		// write a cover statement that will result in the desired combination
+		cover(bank_w == 1 && bank_g == 1 && bank_c == 1);
 
 		// don't leave wolf and goat unattended
-		if (bank_w != bank_m) begin
+		if (bank_w != bank_person) begin
 			assume (bank_w != bank_g);
 		end
 
 		// don't leave goat and cabbage unattended
-		if (bank_g != bank_m) begin
+		if (bank_g != bank_person) begin
 			assume (bank_g != bank_c);
 		end
-
-		// man travels and takes the selected item with him
-		if (w && (bank_w == bank_m)) bank_w <= !bank_m;
-		if (g && (bank_g == bank_m)) bank_g <= !bank_m;
-		if (c && (bank_c == bank_m)) bank_c <= !bank_m;
-		bank_m <= !bank_m;
 	end
 endmodule