X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/1d97a0955e863b7dc7bbe4350bcef8c2047768d8..8e30fdaf6744e2006ade689e6f7b89ee536449d0:/Terminal.v

diff --git a/Terminal.v b/Terminal.v
index 9dc5a21..9ddd5d3 100644
--- a/Terminal.v
+++ b/Terminal.v
@@ -7,11 +7,20 @@ module Terminal(
 	output reg cp_busy,
 	input cp_rnw,
 	output reg [31:0] cp_read = 0,
-	input [31:0] cp_write);
+	input [31:0] cp_write
+`ifdef verilator
+`else
+	, output reg [8:0] sys_odata = 0,
+	input [8:0] sys_idata,
+	output reg sys_tookdata = 0
+`endif
+);
 	
 	/* Terminal pretends to be cp5. */
 	reg towrite = 0;
 	reg [7:0] data = 0;
+	reg [8:0] indata = 0;	/* High bit is if data is present. */
+	reg didread = 0;
 	
 	always @(*)
 	begin
@@ -19,15 +28,36 @@ module Terminal(
 		data = 8'hxx;
 		cp_ack = 0;
 		cp_busy = 0;
+		cp_read = 0;
+		didread = 0;
 		if (cp_req && (cp_rnw == 0) && (cp_insn[27:24] == 4'b1110) && (cp_insn[19:16] == 4'b0000) && (cp_insn[11:8] == 4'h5))
 		begin
 			towrite = 1;
 			data = cp_write[7:0];
 			cp_ack = 1;
+		end else if (cp_req && (cp_rnw == 1) && (cp_insn[27:24] == 4'b1110) && (cp_insn[19:16] == 4'b0001) && (cp_insn[11:8] == 4'h5))
+		begin
+			cp_read = {23'h0, indata[8:0]};
+			cp_ack = 1;
+			didread = cp_insn[7:5] == 1;
 		end
 	end
-	
+`ifdef verilator	
 	always @(posedge clk)
 		if (towrite)
 			$c("{extern void term_output(unsigned char d); term_output(",data,");}");
+		else if (didread || !indata[8])
+			indata = $c("({extern unsigned int term_input(); term_input();})");
+`else
+	always @(posedge clk)
+	begin
+		sys_odata = {towrite,data};
+		if (didread || !indata[8])
+		begin
+			indata = sys_idata;
+			sys_tookdata = 1;
+		end else
+			sys_tookdata = 0;
+	end
+`endif
 endmodule