X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/a85b19a7c7e7fecb4e71c41b37fb30dabaf8bd14..20204e795d54fb0758a79f0abd5fb443c0178a54:/GBZ80Core.v?ds=inline

diff --git a/GBZ80Core.v b/GBZ80Core.v
index 1bc8f78..e125225 100644
--- a/GBZ80Core.v
+++ b/GBZ80Core.v
@@ -39,6 +39,7 @@
 `define INSN_CALL				8'b11001101
 `define INSN_JP_imm			8'b11000011
 `define INSN_JPCC_imm		8'b110xx010
+`define INSN_ALU_A		8'b00xxx111
 
 `define INSN_cc_NZ			2'b00
 `define INSN_cc_Z				2'b01
@@ -69,6 +70,14 @@
 `define INSN_alu_XOR		3'b101
 `define INSN_alu_OR		3'b110
 `define INSN_alu_CP		3'b111		// Oh lawd, is dat some CP?
+`define INSN_alu_RLCA		3'b000
+`define INSN_alu_RRCA		3'b001
+`define INSN_alu_RLA		3'b010
+`define INSN_alu_RRA		3'b011
+`define INSN_alu_DAA		3'b100
+`define INSN_alu_CPL		3'b101
+`define INSN_alu_SCF		3'b110
+`define INSN_alu_CCF		3'b111
 
 module GBZ80Core(
 	input clk,
@@ -280,7 +289,7 @@ module GBZ80Core(
 						`INSN_stack_HL:	wdata <= registers[`REG_L];
 						endcase
 					end
-				2:	begin /* TWIDDLE OUR FUCKING THUMBS! */ end
+				2:	begin /* Twiddle thumbs. */ end
 				3:	begin
 						`EXEC_NEWCYCLE;
 						`EXEC_INC_PC;
@@ -357,6 +366,10 @@ module GBZ80Core(
 					endcase
 				end
 			end
+			`INSN_ALU_A: begin
+				`EXEC_NEWCYCLE;
+				`EXEC_INC_PC;
+			end
 			`INSN_NOP: begin
 				`EXEC_NEWCYCLE;
 				`EXEC_INC_PC;
@@ -443,13 +456,14 @@ module GBZ80Core(
 						rd <= 1;
 					end
 				2:	begin
+						`EXEC_INC_PC;
 						if (!opcode[0]) begin	// i.e., JP cc,nn
 							/* We need to check the condition code to bail out. */
 							case (opcode[4:3])
 							`INSN_cc_NZ:	if (registers[`REG_F][7]) begin `EXEC_NEWCYCLE; end
-							`INSN_cc_Z:		if (!registers[`REG_F][7]) begin `EXEC_NEWCYCLE; end
+							`INSN_cc_Z:		if (~registers[`REG_F][7]) begin `EXEC_NEWCYCLE; end
 							`INSN_cc_NC:	if (registers[`REG_F][4]) begin `EXEC_NEWCYCLE; end
-							`INSN_cc_C:		if (!registers[`REG_F][4]) begin `EXEC_NEWCYCLE; end
+							`INSN_cc_C:		if (~registers[`REG_F][4]) begin `EXEC_NEWCYCLE; end
 							endcase
 						end
 					end
@@ -622,6 +636,28 @@ module GBZ80Core(
 							  registers[`REG_F][3:0]
 							};
 					end
+					`INSN_alu_SUB: begin
+						registers[`REG_A] <=
+							registers[`REG_A] - tmp;
+						registers[`REG_F] <=
+							{ /* Z */ ((registers[`REG_A] - tmp) == 0) ? 1'b1 : 1'b0,
+							  /* N */ 1'b1,
+							  /* H */ (({1'b0,registers[`REG_A][3:0]} - {1'b0,tmp[3:0]}) >> 4 == 1) ? 1'b1 : 1'b0,
+							  /* C */ (({1'b0,registers[`REG_A]} - {1'b0,tmp}) >> 8 == 1) ? 1'b1 : 1'b0,
+							  registers[`REG_F][3:0]
+							};
+					end
+					`INSN_alu_SBC: begin
+						registers[`REG_A] <=
+							registers[`REG_A] - (tmp + {7'b0,registers[`REG_F][4]});
+						registers[`REG_F] <=
+							{ /* Z */ ((registers[`REG_A] - (tmp + {7'b0,registers[`REG_F][4]})) == 0) ? 1'b1 : 1'b0,
+							  /* N */ 1'b1,
+							  /* H */ (({1'b0,registers[`REG_A][3:0]} - ({1'b0,tmp[3:0]} + {4'b0,registers[`REG_F][4]})) >> 4 == 1) ? 1'b1 : 1'b0,
+							  /* C */ (({1'b0,registers[`REG_A]} - ({1'b0,tmp} + {8'b0,registers[`REG_F][4]})) >> 8 == 1) ? 1'b1 : 1'b0,
+							  registers[`REG_F][3:0]
+							};
+					end
 					`INSN_alu_AND: begin
 						registers[`REG_A] <=
 							registers[`REG_A] & tmp;
@@ -649,11 +685,50 @@ module GBZ80Core(
 							  registers[`REG_F][3:0]
 							};
 					end
+					`INSN_alu_CP: begin
+						registers[`REG_F] <=
+							{ /* Z */ ((registers[`REG_A] - tmp) == 0) ? 1'b1 : 1'b0,
+							  /* N */ 1'b1,
+							  /* H */ (({1'b0,registers[`REG_A][3:0]} - {1'b0,tmp[3:0]}) >> 4 == 1) ? 1'b1 : 1'b0,
+							  /* C */ (({1'b0,registers[`REG_A]} - {1'b0,tmp}) >> 8 == 1) ? 1'b1 : 1'b0,
+							  registers[`REG_F][3:0]
+							};
+					end
 					default:
 						$stop;
 					endcase
 				end
 			end
+			`INSN_ALU_A: begin
+				case(opcode[5:3])
+				`INSN_alu_RLCA: begin
+					registers[`REG_A] <= {registers[`REG_A][6:0],registers[`REG_A][7]};
+					registers[`REG_F] <= {registers[`REG_F][7:5],registers[`REG_A][7],registers[`REG_F][3:0]};
+				end
+				`INSN_alu_RRCA: begin
+					registers[`REG_A] <= {registers[`REG_A][0],registers[`REG_A][7:1]};
+					registers[`REG_F] <= {registers[`REG_F][7:5],registers[`REG_A][0],registers[`REG_F][3:0]};
+				end
+				`INSN_alu_RLA: begin
+					registers[`REG_A] <= {registers[`REG_A][6:0],registers[`REG_F][4]};
+					registers[`REG_F] <= {registers[`REG_F][7:5],registers[`REG_A][7],registers[`REG_F][3:0]};
+				end
+				`INSN_alu_RRA: begin
+					registers[`REG_A] <= {registers[`REG_A][4],registers[`REG_A][7:1]};
+					registers[`REG_F] <= {registers[`REG_F][7:5],registers[`REG_A][0],registers[`REG_F][3:0]};
+				end
+				`INSN_alu_CPL: begin
+					registers[`REG_A] <= ~registers[`REG_A];
+					registers[`REG_F] <= {registers[`REG_F][7],1'b1,1'b1,registers[`REG_F][4:0]};
+				end
+				`INSN_alu_SCF: begin
+					registers[`REG_F] <= {registers[`REG_F][7:5],1,registers[`REG_F][3:0]};
+				end
+				`INSN_alu_CCF: begin
+					registers[`REG_F] <= {registers[`REG_F][7:5],~registers[`REG_F][4],registers[`REG_F][3:0]};
+				end
+				endcase
+			end
 			`INSN_NOP: begin /* NOP! */ end
 			`INSN_RST: begin
 				case (cycle)