`define INSN_LD_HL_reg 8'b01110xxx
`define INSN_LD_reg_HL 8'b01xxx110
`define INSN_LD_reg_reg 8'b01xxxxxx
+`define INSN_LD_reg_imm16 8'b00xx0001
+`define INSN_LD_SP_HL 8'b11111001
`define INSN_reg_A 3'b111
`define INSN_reg_B 3'b000
`define INSN_reg_C 3'b001
`define INSN_reg_H 3'b100
`define INSN_reg_L 3'b101
`define INSN_reg_dHL 3'b110
-
+`define INSN_reg16_BC 2'b00
+`define INSN_reg16_DE 2'b01
+`define INSN_reg16_HL 2'b10
+`define INSN_reg16_SP 2'b11
module GBZ80Core(
input clk,
output reg [15:0] busaddress, /* BUS_* is latched on STATE_FETCH. */
endcase
end
`INSN_HALT: begin
- /* XXX UNIMP */
+ `EXEC_NEWCYCLE;
+ /* XXX Interrupts needed for HALT. */
end
`INSN_LD_HL_reg: begin
- /* XXX UNIMP */
+ case (cycle)
+ 0: begin
+ case (opcode[2:0])
+ `INSN_reg_A: begin wdata <= registers[`REG_A]; end
+ `INSN_reg_B: begin wdata <= registers[`REG_B]; end
+ `INSN_reg_C: begin wdata <= registers[`REG_C]; end
+ `INSN_reg_D: begin wdata <= registers[`REG_D]; end
+ `INSN_reg_E: begin wdata <= registers[`REG_E]; end
+ `INSN_reg_H: begin wdata <= registers[`REG_H]; end
+ `INSN_reg_L: begin wdata <= registers[`REG_L]; end
+ endcase
+ address <= {registers[`REG_H], registers[`REG_L]};
+ wr <= 1; rd <= 0;
+ end
+ 1: begin
+ `EXEC_INC_PC;
+ `EXEC_NEWCYCLE;
+ end
+ endcase
end
`INSN_LD_reg_HL: begin
- /* XXX UNIMP */
+ case(cycle)
+ 0: begin
+ address <= {registers[`REG_H], registers[`REG_L]};
+ wr <= 0; rd <= 1;
+ end
+ 1: begin
+ tmp <= rdata;
+ `EXEC_INC_PC;
+ `EXEC_NEWCYCLE;
+ end
+ endcase
end
`INSN_LD_reg_reg: begin
`EXEC_INC_PC;
`INSN_reg_L: begin tmp <= registers[`REG_L]; end
endcase
end
+ `INSN_LD_reg_imm16: begin
+ `EXEC_INC_PC;
+ case (cycle)
+ 0: begin
+ `EXEC_NEXTADDR_PCINC;
+ rd <= 1;
+ end
+ 1: begin
+ `EXEC_NEXTADDR_PCINC;
+ rd <= 1;
+ end
+ 2: begin `EXEC_NEWCYCLE; end
+ endcase
+ end
+ `INSN_LD_SP_HL: begin
+ case (cycle)
+ 0: begin
+ rd <= 0;
+ address <= 16'bxxxxxxxxxxxxxxxx;
+ tmp <= registers[`REG_H];
+ end
+ 1: begin
+ `EXEC_NEWCYCLE;
+ `EXEC_INC_PC;
+ tmp <= registers[`REG_L];
+ end
+ endcase
+ end
+ default:
+ $stop;
endcase
state <= `STATE_WRITEBACK;
end
`STATE_WRITEBACK: begin
casex (opcode)
- `INSN_LD_reg_imm8:
- case (cycle)
- 0: cycle <= 1;
- 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;
- endcase
- 2: cycle <= 0;
- endcase
- `INSN_HALT: begin
- /* XXX UNIMP */
- end
- `INSN_LD_HL_reg: begin
- /* XXX UNIMP */
- end
- `INSN_LD_reg_HL: begin
- /* XXX UNIMP */
- end
- `INSN_LD_reg_reg: begin
- case (opcode[5:3])
- `INSN_reg_A: begin registers[`REG_A] <= tmp; end
- `INSN_reg_B: begin registers[`REG_B] <= tmp; end
- `INSN_reg_C: begin registers[`REG_C] <= tmp; end
- `INSN_reg_D: begin registers[`REG_D] <= tmp; end
- `INSN_reg_E: begin registers[`REG_E] <= tmp; end
- `INSN_reg_H: begin registers[`REG_H] <= tmp; end
- `INSN_reg_L: begin registers[`REG_L] <= tmp; end
+ `INSN_LD_reg_imm8:
+ case (cycle)
+ 0: cycle <= 1;
+ 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;
endcase
- end
+ 2: cycle <= 0;
+ 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
+ end
+ `INSN_LD_reg_HL: begin
+ case (cycle)
+ 0: cycle <= 1;
+ 1: begin
+ case (opcode[5:3])
+ `INSN_reg_A: begin registers[`REG_A] <= tmp; end
+ `INSN_reg_B: begin registers[`REG_B] <= tmp; end
+ `INSN_reg_C: begin registers[`REG_C] <= tmp; end
+ `INSN_reg_D: begin registers[`REG_D] <= tmp; end
+ `INSN_reg_E: begin registers[`REG_E] <= tmp; end
+ `INSN_reg_H: begin registers[`REG_H] <= tmp; end
+ `INSN_reg_L: begin registers[`REG_L] <= tmp; end
+ endcase
+ cycle <= 0;
+ end
+ endcase
+ end
+ `INSN_LD_reg_reg: begin
+ case (opcode[5:3])
+ `INSN_reg_A: begin registers[`REG_A] <= tmp; end
+ `INSN_reg_B: begin registers[`REG_B] <= tmp; end
+ `INSN_reg_C: begin registers[`REG_C] <= tmp; end
+ `INSN_reg_D: begin registers[`REG_D] <= tmp; end
+ `INSN_reg_E: begin registers[`REG_E] <= tmp; end
+ `INSN_reg_H: begin registers[`REG_H] <= tmp; end
+ `INSN_reg_L: begin registers[`REG_L] <= tmp; end
+ endcase
+ end
+ `INSN_LD_reg_imm16: begin
+ case (cycle)
+ 0: cycle <= 1;
+ 1: begin
+ case (opcode[5:4])
+ `INSN_reg16_BC: registers[`REG_C] <= rdata;
+ `INSN_reg16_DE: registers[`REG_E] <= 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_BC: registers[`REG_B] <= rdata;
+ `INSN_reg16_DE: registers[`REG_D] <= rdata;
+ `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
+ endcase
+ end
endcase
state <= `STATE_FETCH;
end
git.joshuawise.com / fpgaboy.git / blobdiff