registers[ 9] <= 0;
registers[10] <= 0;
registers[11] <= 0;
+ ie <= 0;
+ rd <= 1;
+ wr <= 0;
+ newcycle <= 1;
+ state <= 0;
+ cycle <= 0;
end
always @(posedge clk)
case (state)
`STATE_FETCH: begin
- if (wr)
- buswdata <= wdata;
- if (newcycle)
+ if (newcycle) begin
busaddress <= {registers[`REG_PCH], registers[`REG_PCL]};
- else
+ buswr <= 0;
+ busrd <= 1;
+ end else begin
busaddress <= address;
- buswr <= wr;
- busrd <= rd;
+ buswr <= wr;
+ busrd <= rd;
+ if (wr)
+ buswdata <= wdata;
+ end
state <= `STATE_DECODE;
end
`STATE_DECODE: begin
rdata <= busdata;
newcycle <= 0;
cycle <= 0;
- end else
+ end else begin
if (rd) rdata <= busdata;
+ cycle <= cycle + 1;
+ end
buswr <= 0;
busrd <= 0;
wr <= 0;
casex (opcode)
`INSN_LD_reg_imm8:
case (cycle)
- 0: cycle <= 1;
+ 0: begin end
1: case (opcode[5:3])
- `INSN_reg_A: begin registers[`REG_A] <= rdata; cycle <= 0; end
- `INSN_reg_B: begin registers[`REG_B] <= rdata; cycle <= 0; end
- `INSN_reg_C: begin registers[`REG_C] <= rdata; cycle <= 0; end
- `INSN_reg_D: begin registers[`REG_D] <= rdata; cycle <= 0; end
- `INSN_reg_E: begin registers[`REG_E] <= rdata; cycle <= 0; end
- `INSN_reg_H: begin registers[`REG_H] <= rdata; cycle <= 0; end
- `INSN_reg_L: begin registers[`REG_L] <= rdata; cycle <= 0; end
- `INSN_reg_dHL: cycle <= 2;
+ `INSN_reg_A: begin registers[`REG_A] <= rdata; end
+ `INSN_reg_B: begin registers[`REG_B] <= rdata; end
+ `INSN_reg_C: begin registers[`REG_C] <= rdata; end
+ `INSN_reg_D: begin registers[`REG_D] <= rdata; end
+ `INSN_reg_E: begin registers[`REG_E] <= rdata; end
+ `INSN_reg_H: begin registers[`REG_H] <= rdata; end
+ `INSN_reg_L: begin registers[`REG_L] <= rdata; end
+ `INSN_reg_dHL: begin /* Go off to cycle 2 */ end
endcase
- 2: cycle <= 0;
+ 2: begin end
endcase
`INSN_HALT: begin
/* Nothing needs happen here. */
/* XXX Interrupts needed for HALT. */
end
`INSN_LD_HL_reg: begin
- case (cycle)
- 0: cycle <= 1;
- 1: cycle <= 0;
- endcase
+ /* Nothing of interest here */
end
`INSN_LD_reg_HL: begin
case (cycle)
- 0: cycle <= 1;
+ 0: begin end
1: begin
case (opcode[5:3])
`INSN_reg_A: registers[`REG_A] <= tmp;
`INSN_reg_H: registers[`REG_H] <= tmp;
`INSN_reg_L: registers[`REG_L] <= tmp;
endcase
- cycle <= 0;
end
endcase
end
end
`INSN_LD_reg_imm16: begin
case (cycle)
- 0: cycle <= 1;
+ 0: begin /* */ end
1: begin
case (opcode[5:4])
`INSN_reg16_BC: registers[`REG_C] <= rdata;
`INSN_reg16_HL: registers[`REG_L] <= rdata;
`INSN_reg16_SP: registers[`REG_SPL] <= rdata;
endcase
- cycle <= 2;
end
2: begin
case (opcode[5:4])
`INSN_reg16_HL: registers[`REG_H] <= rdata;
`INSN_reg16_SP: registers[`REG_SPH] <= rdata;
endcase
- cycle <= 0;
end
endcase
end
`INSN_LD_SP_HL: begin
case (cycle)
- 0: begin
- cycle <= 1;
- registers[`REG_SPH] <= tmp;
- end
- 1: begin
- cycle <= 0;
- registers[`REG_SPL] <= tmp;
- end
+ 0: registers[`REG_SPH] <= tmp;
+ 1: registers[`REG_SPL] <= tmp;
endcase
end
`INSN_PUSH_reg: begin /* PUSH is 16 cycles! */
case (cycle)
- 0: begin
- {registers[`REG_SPH],registers[`REG_SPL]} <=
- {registers[`REG_SPH],registers[`REG_SPL]} - 1;
- cycle <= 1;
- end
- 1: begin
- {registers[`REG_SPH],registers[`REG_SPL]} <=
- {registers[`REG_SPH],registers[`REG_SPL]} - 1;
- cycle <= 2;
- end
- 2: cycle <= 3;
- 3: cycle <= 0;
+ 0: {registers[`REG_SPH],registers[`REG_SPL]} <=
+ {registers[`REG_SPH],registers[`REG_SPL]} - 1;
+ 1: {registers[`REG_SPH],registers[`REG_SPL]} <=
+ {registers[`REG_SPH],registers[`REG_SPL]} - 1;
+ 2: begin /* type F */ end
+ 3: begin /* type F */ end
endcase
end
`INSN_POP_reg: begin /* POP is 12 cycles! */
case (cycle)
- 0: begin
- cycle <= 1;
- {registers[`REG_SPH],registers[`REG_SPL]} <=
- {registers[`REG_SPH],registers[`REG_SPL]} + 1;
- end
+ 0: {registers[`REG_SPH],registers[`REG_SPL]} <=
+ {registers[`REG_SPH],registers[`REG_SPL]} + 1;
1: begin
case (opcode[5:4])
`INSN_stack_AF: registers[`REG_F] <= rdata;
endcase
{registers[`REG_SPH],registers[`REG_SPL]} <=
{registers[`REG_SPH],registers[`REG_SPL]} + 1;
- cycle <= 2;
end
2: begin
case (opcode[5:4])
`INSN_stack_DE: registers[`REG_D] <= rdata;
`INSN_stack_HL: registers[`REG_H] <= rdata;
endcase
- cycle <= 0;
end
endcase
end
`INSN_LDH_AC: begin
case (cycle)
- 0: cycle <= 1;
- 1: begin
- cycle <= 0;
- if (opcode[4])
- registers[`REG_A] <= rdata;
- end
+ 0: begin /* Type F */ end
+ 1: if (opcode[4])
+ registers[`REG_A] <= rdata;
endcase
end
`INSN_LDx_AHL: begin
case (cycle)
- 0: cycle <= 1;
+ 0: begin /* Type F */ end
1: begin
- cycle <= 0;
if (opcode[3])
registers[`REG_A] <= rdata;
{registers[`REG_H],registers[`REG_L]} <=
`INSN_ALU8: begin
if ((opcode[2:0] == `INSN_reg_dHL) && (cycle == 0)) begin
/* Sit on our asses. */
- cycle <= 1;
end else begin /* Actually do the computation! */
case (opcode[5:3])
`INSN_alu_ADD: begin
`INSN_NOP: begin /* NOP! */ end
`INSN_RST: begin
case (cycle)
- 0: cycle <= 1;
- 1: cycle <= 2;
- 2: cycle <= 3;
- 3: begin
- cycle <= 0;
- {registers[`REG_SPH],registers[`REG_SPL]} <=
- {registers[`REG_SPH],registers[`REG_SPL]}-2;
- end
+ 0: begin /* type F */ end
+ 1: begin /* type F */ end
+ 2: begin /* type F */ end
+ 3: {registers[`REG_SPH],registers[`REG_SPL]} <=
+ {registers[`REG_SPH],registers[`REG_SPL]}-2;
endcase
end
`INSN_RET: begin
case (cycle)
- 0: cycle <= 1;
- 1: begin
- cycle <= 2;
- registers[`REG_PCL] <= rdata;
- end
- 2: begin
- cycle <= 3;
- registers[`REG_PCH] <= rdata;
- end
+ 0: begin /* type F */ end
+ 1: registers[`REG_PCL] <= rdata;
+ 2: registers[`REG_PCH] <= rdata;
3: begin
- cycle <= 0;
{registers[`REG_SPH],registers[`REG_SPL]} <=
{registers[`REG_SPH],registers[`REG_SPL]} + 2;
if (opcode[4]) /* RETI */
end
`INSN_CALL: begin
case (cycle)
- 0: cycle <= 1;
- 1: begin
- cycle <= 2;
- tmp <= rdata; // tmp contains newpcl
- end
- 2: begin
- cycle <= 3;
- tmp2 <= rdata; // tmp2 contains newpch
- end
- 3: begin
- cycle <= 4;
- end
- 4: begin
- cycle <= 5;
- registers[`REG_PCH] <= tmp2;
- end
+ 0: begin /* type F */ end
+ 1: tmp <= rdata; // tmp contains newpcl
+ 2: tmp2 <= rdata; // tmp2 contains newpch
+ 3: begin /* type F */ end
+ 4: registers[`REG_PCH] <= tmp2;
5: begin
{registers[`REG_SPH],registers[`REG_SPL]} <=
{registers[`REG_SPH],registers[`REG_SPL]} - 2;
registers[`REG_PCL] <= tmp;
- cycle <= 0;
end
endcase
end
module ROM(
input [15:0] address,
inout [7:0] data,
+ input clk,
input wr, rd);
reg [7:0] rom [2047:0];
initial $readmemh("rom.hex", rom);
wire decode = address[15:13] == 0;
- reg [7:0] odata;
- wire idata = data;
+ wire [7:0] odata = rom[address[11:0]];
assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
-
- always @(posedge rd)
- if (decode)
- odata <= rom[address];
+ //assign data = rd ? odata : 8'bzzzzzzzz;
endmodule
module InternalRAM(
wire idata = data;
assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
- reg [13:0] diq;
- initial
- for (diq = 0; diq < 8191; diq = diq + 1)
- ram[diq] = 8'h43;
-
always @(negedge clk)
begin
if (decode && rd)
odata <= ram[address[12:0]];
- if (decode && wr)
+ else if (decode && wr)
ram[address[12:0]] <= data;
end
endmodule
-module TestBench();
- reg clk = 0;
+//module Switches(
+// input [15:0] address,
+// inout [7:0] data,
+// input clk,
+// input wr, rd,
+// input [7:0] switches,
+// output reg [7:0] ledout);
+
+// wire decode = address == 16'hFF51;
+// reg [7:0] odata;
+// wire idata = data;
+// assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
+
+// always @(negedge clk)
+// begin
+// if (decode && rd)
+// odata <= switches;
+// else if (decode && wr)
+// ledout <= data;
+// end
+//endmodule
+
+module CoreTop(
+ input iclk, xtal,
+ output wire [7:0] leds,
+ output serio,
+ output wire [3:0] digits,
+ output wire [7:0] seven);
+
+ wire clk;
+ //IBUFG ibuf (.O(clk), .I(iclk));
+
+ CPUDCM dcm (.CLKIN_IN(xtal), .CLKFX_OUT(clk));
+
wire [15:0] addr;
wire [7:0] data;
wire wr, rd;
- always #10 clk <= ~clk;
+ assign leds = iclk?{rd,wr,addr[5:0]}:data[7:0];
+
GBZ80Core core(
.clk(clk),
.busaddress(addr),
ROM rom(
.address(addr),
.data(data),
+ .clk(clk),
.wr(wr),
.rd(rd));
- InternalRAM ram(
+ AddrMon amon(
+ .addr(addr),
+ .clk(xtal),
+ .digit(digits),
+ .out(seven)
+ );
+
+ assign serio = 0;
+endmodule
+
+module TestBench();
+ reg clk = 0;
+ wire [15:0] addr;
+ wire [7:0] data;
+ wire wr, rd;
+
+// wire [7:0] leds;
+// wire [7:0] switches;
+
+ always #10 clk <= ~clk;
+ GBZ80Core core(
+ .clk(clk),
+ .busaddress(addr),
+ .busdata(data),
+ .buswr(wr),
+ .busrd(rd));
+
+ ROM rom(
+ .clk(clk),
.address(addr),
.data(data),
- .clk(clk),
.wr(wr),
.rd(rd));
+
+// InternalRAM ram(
+// .address(addr),
+// .data(data),
+// .clk(clk),
+// .wr(wr),
+// .rd(rd));
+
+// wire serio;
+// UART uart(
+// .addr(addr),
+// .data(data),
+// .clk(clk),
+// .wr(wr),
+// .rd(rd),
+// .serial(serio));
+
+// Switches sw(
+// .clk(clk),
+// .address(addr),
+// .data(data),
+// .wr(wr),
+// .rd(rd),
+// .switches(switches),
+// .leds(leds));
endmodule
git.joshuawise.com / fpgaboy.git / blobdiff