X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/25f4912ce5d2a6c70a9f604502303a17359b19ec..f8c46ff554cb7f4c067eab1234faf729118c4c25:/core/insn_alu_a.v

diff --git a/core/insn_alu_a.v b/core/insn_alu_a.v
index a5e1c1c..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
@@ -35,15 +47,24 @@
 			`_A <= {`_F[4],`_A[7:1]};
 			`_F <= {`_F[7:5],`_A[0],`_F[3:0]};
 		end
+		`INSN_alu_DAA: begin
+			`_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