module GBZ80Core(
input clk,
- output reg [15:0] busaddress, /* BUS_* is latched on STATE_FETCH. */
- inout [7:0] busdata,
- output reg buswr, output reg busrd,
+ inout [15:0] bus0address, /* BUS_* is latched on STATE_FETCH. */
+ inout [7:0] bus0data,
+ inout bus0wr, bus0rd,
+ inout [15:0] bus1address, /* BUS_* is latched on STATE_FETCH. */
+ inout [7:0] bus1data,
+ inout bus1wr, bus1rd,
input irq, input [7:0] jaddr,
output reg [1:0] state);
reg [7:0] tmp, tmp2; /* Generic temporary regs. */
reg [7:0] buswdata;
- assign busdata = buswr ? buswdata : 8'bzzzzzzzz;
+ wire [7:0] busdata;
+
+ reg [15:0] busaddress;
+ reg buswr, busrd;
+
+ reg bootstrap_enb;
+
+ wire bus = ((busaddress[15:8] == 8'h00) && bootstrap_enb) || ((busaddress[15:7] == 9'b111111111) && (busaddress != 16'hFFFF)); /* 0 or 1 depending on which bus */
+
+ assign bus0address = (bus == 0) ? busaddress : 16'bzzzzzzzzzzzzzzz;
+ assign bus1address = (bus == 1) ? busaddress : 16'bzzzzzzzzzzzzzzz;
+ assign bus0data = ((bus == 0) && buswr) ? buswdata : 8'bzzzzzzzz;
+ assign bus1data = ((bus == 1) && buswr) ? buswdata : 8'bzzzzzzzz;
+ assign busdata = (bus == 0) ? bus0data : bus1data;
+ assign bus0rd = (bus == 0) ? busrd : 1'bz;
+ assign bus1rd = (bus == 1) ? busrd : 1'bz;
+ assign bus0wr = (bus == 0) ? buswr : 1'bz;
+ assign bus1wr = (bus == 1) ? buswr : 1'bz;
reg ie, iedelay;
state <= `STATE_WRITEBACK;
cycle <= 0;
twobyte <= 0;
+ bootstrap_enb <= 1;
end
always @(posedge clk)