X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/3ad960bdb71efcbb1dfd436163085da0d70eb699..df770340caf8ecd26a55179484edb507082bd5c6:/insn_incdec16.v

diff --git a/insn_incdec16.v b/insn_incdec16.v
new file mode 100644
index 0000000..01f919c
--- /dev/null
+++ b/insn_incdec16.v
@@ -0,0 +1,59 @@
+`ifdef EXECUTE
+	`INSN_INCDEC16: begin
+		case (cycle)
+		0:	begin
+				case (opcode[5:4])
+				`INSN_reg16_BC:	begin
+					tmp <= registers[`REG_B];
+					tmp2 <= registers[`REG_C];
+				end
+				`INSN_reg16_DE:	begin
+					tmp <= registers[`REG_D];
+					tmp2 <= registers[`REG_E];
+				end
+				`INSN_reg16_HL:	begin
+					tmp <= registers[`REG_H];
+					tmp2 <= registers[`REG_L];
+				end
+				`INSN_reg16_SP:	begin
+					tmp <= registers[`REG_SPH];
+					tmp2 <= registers[`REG_SPL];
+				end
+				endcase
+			end
+		1:	begin
+				`EXEC_INC_PC;
+				`EXEC_NEWCYCLE;
+			end
+		endcase
+	end
+`endif
+
+`ifdef WRITEBACK
+	`INSN_INCDEC16: begin
+		case (cycle)
+		0:	{tmp,tmp2} <= {tmp,tmp2} +
+				(opcode[3] ? 16'hFFFF : 16'h0001);
+		1: begin
+				case (opcode[5:4])
+				`INSN_reg16_BC:	begin
+					registers[`REG_B] <= tmp;
+					registers[`REG_C] <= tmp2;
+				end
+				`INSN_reg16_DE:	begin
+					registers[`REG_D] <= tmp;
+					registers[`REG_E] <= tmp2;
+				end
+				`INSN_reg16_HL:	begin
+					registers[`REG_H] <= tmp;
+					registers[`REG_L] <= tmp2;
+				end
+				`INSN_reg16_SP:	begin
+					registers[`REG_SPH] <= tmp;
+					registers[`REG_SPL] <= tmp2;
+				end
+				endcase
+			end
+		endcase
+	end
+`endif