Fixed video, kbd and buzzer

cpu/toplevel/tb_iorq.sv

@@ -0,0 +1,32 @@
+//--------------------------------------------------------------
+// Interrupt test for simulation
+// This model injects an interrupt opcode on the bus
+//--------------------------------------------------------------
+module iorq (Data, M1, IORQ);
+
+// Set to 1 if you want debug printout on each IO access
+int debug = 0;
+
+inout [7:0] Data;
+input M1, IORQ;
+
+// Define the opcode to be sent through IORQ (FF=RST38, C7=RST0,...)
+
+// To test interrupts in mode 0, uncommend one of these lines (pushed opcode):
+//`define OPCODE  8'hFF
+//`define OPCODE  8'hC7
+
+// To test interrupts in mode 2, uncommend this line (this is a vector):
+`define OPCODE  8'h80
+
+// Return data on an IORQ condition
+assign Data = (!M1 && !IORQ) ? `OPCODE : {8{1'bz}};
+
+int fd;
+
+always @(!M1 && !IORQ) begin
+    if (debug)
+        $strobe("[IORQ] DB=%H", `OPCODE);
+end
+
+endmodule