X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/f327eee1f228769c4753a3f2279063c99f6f1ab0..f8c46ff554cb7f4c067eab1234faf729118c4c25:/core/insn_alu_a.v

diff --git a/core/insn_alu_a.v b/core/insn_alu_a.v
index 80d317d..5fbadee 100644
--- a/core/insn_alu_a.v
+++ b/core/insn_alu_a.v
@@ -9,6 +9,18 @@
 
 `define INSN_ALU_A		9'b000xxx111
 
+`ifdef LOCALWIRES
+	/* Y U Q */
+	/* Derived from MESS opc_main.h */
+	wire [8:0] daa_tmp_n0_h = ((`_F & `FLAG_H) || (`_A[3:0] > 9)) ? {1'b0,`_A} + 9'h06 : {1'b0,`_A};
+	wire [8:0] daa_tmp_n0 = ((`_F & `FLAG_C) || (daa_tmp_n0_h[8:4] > 9)) ? daa_tmp_n0_h + 9'h60 : daa_tmp_n0_h;
+	
+	wire [8:0] daa_tmp_n_h1 = (`_F & `FLAG_H) ? ({1'b0,`_A} - 9'h06) : {1'b0,`_A};
+	wire [8:0] daa_tmp_n_h2 = ((`_F & `FLAG_H) && !(`_F & `FLAG_C)) ? {1'b0,daa_tmp_n_h1[7:0]} : daa_tmp_n_h1;
+	wire [8:0] daa_tmp_n = (`_F & `FLAG_C) ? (daa_tmp_n_h2 - 9'h60) : daa_tmp_n_h2;
+	wire [8:0] daa_tmp = (`_F & `FLAG_N) ? daa_tmp_n : daa_tmp_n0;
+`endif
+
 `ifdef EXECUTE
 	`INSN_ALU_A: begin
 		`EXEC_NEWCYCLE
@@ -36,86 +48,23 @@
 			`_F <= {`_F[7:5],`_A[0],`_F[3:0]};
 		end
 		`INSN_alu_DAA: begin
-			if (`_F[6]) begin				
-				if (`_F[4]) begin
-					if(`_A[3:0] >= 4'h6 && `_A[7:4] >= 4'h6 && `F[5]) begin
-						`_A <= `_A + 8'h9A;
-						`_F <= {((`_A + 8'h9A) == 8'b0), `_F[6:0]};
-					end
-					else begin
-						`_A <= `_A + 8'hA0;
-						`_F <= {((`_A + 8'hA0) == 8'b0), `_F[6:0]};
-					end
-				end
-				else begin
-					if(`_A[3:0] <= 4'h9 && `_A[7:4] <= 4'h9 && !`_F[5]) begin
-						`_F <= {(`_A == 8'b0), `_F[6:0]};
-					end
-					else begin
-						`_A <= `_A + 8'hFA;
-						`_F <= {((`_A + 8'hFA) == 8'b0), `_F[6:0]};
-					end
-				end
-			end
-			else begin
-				if (`_F[4]) begin
-					if(`_F[5]) begin
-						`_A <= `_A + 8'h66;
-						`_F <= {((`_A + 8'h66) == 8'b0), `_F[6:0]};
-					end
-					else if (`_A[3:0] > 4'b9) begin
-						`_A <= `_A + 8'h66;
-						`_F <= {((`_A + 8'h66) == 8'b0), `_F[6:0]};
-					end
-					else begin
-						`_A <= `_A + 8'h60;
-						`_F <= {((`_A + 8'h60) == 8'b0), `_F[6:0]};
-					end
-				end
-				else begin
-					if(`_F[5]) begin
-						if(`_A[7:4] > 4'h9) begin
-							`_A <= `_A + 8'h66;
-							`_F <= {((`_A + 8'h66) == 8'b0), `_F[6:5], 1'b1, `_F[3:0]};
-						end
-						else begin
-							`_A <= `_A + 8'h06;
-							`_F <= {((`_A + 8'h06) == 8'b0), `_F[6:0]};
-						end
-					end
-					else begin
-						if(`_A[3:0] > 4'h9) begin
-							if (`_A[7:4] > 4'h8) begin
-								`_A <= `_A + 8'h66;
-								`_F <= {((`_A + 8'h66) == 8'b0), `_F[6:5], 1'b1, `_F[3:0]};
-							end
-							else begin
-								`_A <= `_A + 8'h06;
-								`_F <= {((`_A + 8'h06) == 8'b0), `_F[6:0]};
-							end
-						end
-						else begin
-							if (`_A[7:4] > 4'h9) begin
-								`_A <= `_A + 8'h66;
-								`_F <= {((`_A + 8'h66) == 8'b0), `_F[6:5], 1'b1, `_F[3:0]};
-							end
-							else begin
-								`_F <= {(`_A == 8'b0), `_F[6:0]};
-							end
-						end
-					end
-				end
-			end
+			`_A <= daa_tmp[7:0];
+			`_F <= {
+					(daa_tmp[7:0] == 0) ? 1'b1 : 8'b0, /* Z */
+					2'b00, /* NH */
+					daa_tmp[8], /* C */
+					`_F[3:0]
+				};
 		end
 		`INSN_alu_CPL: begin
 			`_A <= ~`_A;
 			`_F <= {`_F[7],1'b1,1'b1,`_F[4:0]};
 		end
 		`INSN_alu_SCF: begin
-			`_F <= {`_F[7:5],1'b1,`_F[3:0]};
+			`_F <= {`_F[7],3'b001,`_F[3:0]};
 		end
 		`INSN_alu_CCF: begin
-			`_F <= {`_F[7:5],~`_F[4],`_F[3:0]};
+			`_F <= {`_F[7],2'b00,~`_F[4],`_F[3:0]};
 		end
 		endcase
 	end