- added double buffer

- added INT_O on buffer change
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git-svn-id: http://moon:8086/svn/vhdl/trunk@641 cc03376c-175c-47c8-b038-4cd826a8556b

lib/VGA_ctrl/src/tb_vga_frontend64.vhd

@@ -40,6 +40,7 @@ ARCHITECTURE behavior OF tb_vga_frontend64 IS
 	signal RST_O			: std_logic := '1';
 
 	-- Master
+	signal INT_O			: std_logic;
 	signal CYC_O			: std_logic;
 	signal STB_O			: std_logic;
 	signal WE_O				: std_logic;
@@ -103,6 +104,7 @@ inst_vga_frontend64 : entity work.vga_frontend64
 		MDAT_O			=> MDAT_I,
 
 		-- JBUS Slave signals
+		INT_O			=> INT_O,
 		CYC_I			=> CYC_O,
 		STB_I			=> STB_O,
 		WE_I			=> WE_O,

lib/VGA_ctrl/src/vga_frontend64.vhd

@@ -51,6 +51,7 @@ entity vga_frontend64 is
 		MDAT_O			: out unsigned(63 downto 0);
 		
 		-- JBUS Slave signals
+		INT_O			: out STD_LOGIC;
 		CYC_I			: in  STD_LOGIC;
 		STB_I			: in  STD_LOGIC;
 		WE_I			: in  STD_LOGIC;
@@ -123,8 +124,14 @@ architecture Behavioral of vga_frontend64 is
 	-- Bus master signals
 	constant MAX_REQUEST_CNT	: natural := tsvga.ts_h.ncyc_scan*tsvga.ts_v.ncyc_scan;
 
-	signal mem_offset			: unsigned(31 downto 0);
+	signal buf_chg				: std_logic;
-	signal vga_mem_offset		: unsigned(31 downto 0);
+	signal buf_chg_irq_en		: std_logic;
+	signal buf_chg_irq			: std_logic;
+	signal buf_chg_irq_ack		: std_logic;
+	signal vga_mem_off_last		: unsigned(31 downto 0);
+	signal vga_mem_off_curr		: unsigned(31 downto 0);
+	signal vga_mem_off_0		: unsigned(31 downto 0);
+	signal vga_mem_off_1		: unsigned(31 downto 0);
 	signal vga_scan_rdy			: std_logic;
 	signal vga_master_en		: std_logic;
 	signal request_cnt_rst		: std_logic;
@@ -141,6 +148,20 @@ architecture Behavioral of vga_frontend64 is
 
 begin
 
+	INT_O	<= buf_chg_irq;
+	
+proc_buf_chg_irq:
+	process(CLK_I)
+	begin
+		if rising_edge(CLK_I) then
+			if RST_I = '1' or buf_chg_irq_ack = '1' then
+				buf_chg_irq	<= '0';
+			elsif buf_chg = '1' then
+				buf_chg_irq	<= buf_chg_irq_en and vga_master_en;
+			end if;
+		end if;
+	end process;	
+
 inst_vga_backend : entity work.vga_backend
 	GENERIC MAP
 	(
@@ -327,20 +348,28 @@ read_counter:
 pixel_counter:
 	process(CLK_I)
 	variable pixel_cnt	: natural range 0 to MAX_REQUEST_CNT/2-1;
+	variable curr		: unsigned(31 downto 0);
+	variable last		: unsigned(31 downto 0);
 	begin
 		if rising_edge(CLK_I) then
+			buf_chg	<= '0';
 			if pixel_cnt_rst = '1' then
 				pixel_cnt	:= 0;
-				mem_offset	<= vga_mem_offset;
+				curr		:= vga_mem_off_0;
+				last		:= vga_mem_off_1;
 			elsif request_cnt_en = '1' and SRDY_I = '1' then
 				if pixel_cnt /= MAX_REQUEST_CNT/2-1 then
 					pixel_cnt 	:= pixel_cnt + 1;
 				else
 					pixel_cnt	:= 0;
-					mem_offset	<= vga_mem_offset;
+					curr		:= vga_mem_off_last;
+					last		:= vga_mem_off_curr;
+					buf_chg		<= '1';
 				end if;	
  			end if;	
- 			ADDR_O	<= mem_offset + (to_unsigned(pixel_cnt, 29) & "000");
+ 			vga_mem_off_curr	<= curr;
+ 			vga_mem_off_last	<= last;
+ 			ADDR_O				<= curr + (to_unsigned(pixel_cnt, 29) & "000");
 		end if;
 	end process;	
 	
@@ -381,7 +410,6 @@ inst_char_gen : entity work.char_gen
 	    char_draw_en	=> cg_draw
     );
 	SRDY_O				<= CYC_I; -- and cg_rdy;
---	SDAT_O				<= X"0000000" & "000" & cg_rdy;
 	MDAT_O				<= (others => '-');
 	scan_rdy			<= stat_hready and stat_vready;
 	cg_en				<= stat_scan;
@@ -401,6 +429,7 @@ registers_read:
 				when "0000" =>
 					SDAT_O(0)			<= cg_rdy;
 					SDAT_O(1)			<= vga_master_en;
+					SDAT_O(2)			<= buf_chg_irq;
 					
 				-- sys_vga_ascii	4
 				when "0001" =>
@@ -418,22 +447,26 @@ registers_read:
 				when "0100" =>
 					SDAT_O				<= to_unsigned(cg_color);
 
-				-- sys_vga_moffs	20
+				-- sys_vga_resx		20
 				when "0101" =>
-					SDAT_O				<= vga_mem_offset;
-
-				-- sys_vga_resx		24
-				when "0110" =>
 					SDAT_O(15 downto 0)	<= to_unsigned(tsvga.ts_h.ncyc_scan, 16);
 
-				-- sys_vga_resy		28
+				-- sys_vga_resy		24
-				when "0111" =>
+				when "0110" =>
 					SDAT_O(15 downto 0)	<= to_unsigned(tsvga.ts_v.ncyc_scan, 16);
 
-				-- sys_vga_fps		32
+				-- sys_vga_fps		28
-				when "1000" =>
+				when "0111" =>
 					SDAT_O(15 downto 0)	<= to_unsigned(tsvga.nfps, 16);
 
+				-- sys_vga_moffs_curr	32
+				when "1000" =>
+					SDAT_O				<= vga_mem_off_curr;
+
+				-- sys_vga_moffs_last	36
+				when "1001" =>
+					SDAT_O				<= vga_mem_off_last;
+
 				when others => null;
 				end case;
 			end if;
@@ -450,10 +483,13 @@ registers_write:
 			cg_posx_we		<= '0';
 			cg_clr_screen	<= '0';
 			cg_clr_line		<= '0';
+			buf_chg_irq_ack	<= '0';
 			if RST_I = '1' then
 				cg_din			<= (others => '0');
 				vga_master_en	<= '0';
-				vga_mem_offset	<= X"40000000";
+				buf_chg_irq_en	<= '0';
+				vga_mem_off_0	<= X"40000000";
+				vga_mem_off_1	<= X"40004000";
 				cg_color		<= (X"FF", X"FF", X"FF", X"FF");
 			elsif (STB_I and CYC_I and WE_I) = '1' then
 				case ADDR_I(5 downto 2) is
@@ -461,6 +497,7 @@ registers_write:
 				-- sys_vga_ctrl		0
 				when "0000" =>
 					vga_master_en	<= SDAT_I(1);
+					buf_chg_irq_ack	<= SDAT_I(2);
 					cg_clr_screen	<= SDAT_I(4);
 					cg_clr_line		<= SDAT_I(5);
 					
@@ -483,9 +520,13 @@ registers_write:
 				when "0100" =>
 					cg_color		<= to_color_t(SDAT_I(31 downto 0));
 
-				-- sys_vga_moffs	20
+				-- sys_vga_moffs0	32
-				when "0101" =>
+				when "1000" =>
-					vga_mem_offset	<= SDAT_I(31 downto 2) & "00";
+					vga_mem_off_0	<= SDAT_I(31 downto 2) & "00";
+					
+				-- sys_vga_moffs1	36
+				when "1001" =>
+					vga_mem_off_1	<= SDAT_I(31 downto 2) & "00";
 					
 				when others => null;
 				end case;