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

diff --git a/insn_rst.v b/insn_rst.v
new file mode 100644
index 0000000..8752034
--- /dev/null
+++ b/insn_rst.v
@@ -0,0 +1,36 @@
+`ifdef EXECUTE
+	`INSN_RST: begin
+		case (cycle)
+		0:	begin
+				`EXEC_INC_PC;		// This goes FIRST in RST
+			end
+		1:	begin
+				wr <= 1;
+				address <= {registers[`REG_SPH],registers[`REG_SPL]}-1;
+				wdata <= registers[`REG_PCH];
+			end
+		2:	begin
+				wr <= 1;
+				address <= {registers[`REG_SPH],registers[`REG_SPL]}-2;
+				wdata <= registers[`REG_PCL];
+			end
+		3:	begin
+				`EXEC_NEWCYCLE;
+				{registers[`REG_PCH],registers[`REG_PCL]} <=
+					{10'b0,opcode[5:3],3'b0};
+			end
+		endcase
+	end
+`endif
+
+`ifdef WRITEBACK
+	`INSN_RST: begin
+		case (cycle)
+		0:	begin /* type F */ end
+		1:	begin /* type F */ end
+		2:	begin /* type F */ end
+		3:	{registers[`REG_SPH],registers[`REG_SPL]} <=
+				{registers[`REG_SPH],registers[`REG_SPL]}-2;
+		endcase
+	end
+`endif