-------------------------------------------------------------------------
-- Project: JCPU, a portable 8-bit RISC CPU written in VHDL
-- This file: testbench for system test using Xilinx ML-402

-- Copyright (C) 2007 J. Ahrensfeld

-- This library is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Lesser General Public
-- License as published by the Free Software Foundation; either
-- version 2.1 of the License, or (at your option) any later version.

-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-- Lesser General Public License for more details.

-- You should have received a copy of the GNU Lesser General Public
-- License along with this library; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

-- For questions and ideas, please contact the author at jens@jayfield.org

-----------------------------------------------------------------------

LIBRARY ieee;
use IEEE.STD_LOGIC_1164.ALL;
USE ieee.numeric_std.ALL;

use work.vga_types.all;

ENTITY tb_vga_frontend64 IS
END tb_vga_frontend64;

ARCHITECTURE behavior OF tb_vga_frontend64 IS 

	constant tsvga			: vga_timespec_t := ts_vga_testbench;
	constant CLK_PERIOD		: time := 10 ns;
	constant VGA_CLK_PERIOD	: time := (integer(1E9) / tsvga.f_pxl_clk) * 1 ns;
	signal CLK_O			: std_logic := '1';
	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;
	signal SEL_O			: unsigned(3 downto 0) := (others => '1');
	signal ACK_I			: std_logic := '0';
	signal MRDY_O			: std_logic := '1';
	signal SRDY_I			: std_logic := '0';
	signal ADDR_O			: unsigned(31 downto 0) := (others => '-');
	signal MDAT_I			: unsigned(63 downto 0) := (others => '-');
	signal MDAT_O			: unsigned(63 downto 0) := (others => '-');

	-- Slave
	signal CYC_I			: std_logic := '0';
	signal STB_I			: std_logic := '0';
	signal WE_I				: std_logic := '0';
	signal SEL_I			: unsigned(7 downto 0);
	signal ACK_O			: std_logic;
	signal MRDY_I			: std_logic;
	signal SRDY_O			: std_logic;
	signal ADDR_I			: unsigned(31 downto 0) := (others => '-');
	signal SDAT_I			: unsigned(31 downto 0) := (others => '-');
	signal SDAT_O			: unsigned(31 downto 0) := (others => '-');
	signal rdy				: std_logic := '0';

	signal read_reg			: unsigned(31 downto 0) := (others => '-');

	-- VGA signals
	signal vga_clk			: std_logic := '1';
	signal vga_red			: unsigned(7 downto 0);
	signal vga_green		: unsigned(7 downto 0);
	signal vga_blue			: unsigned(7 downto 0);
	signal vga_blank_n		: std_logic;
	signal vga_sync_n		: std_logic;
	signal vga_hsync		: std_logic;
	signal vga_vsync		: std_logic;
	signal vga_en			: std_logic;

BEGIN

inst_vga_frontend64 : entity work.vga_frontend64
	GENERIC MAP
	(
		fifo_depth					=> 2048,
		fifo_almost_full_thresh		=> 2048-128,
		fifo_almost_empty_thresh	=> 512,
		tsvga						=> tsvga
	)
	PORT MAP
	(
		-- System signals
		RST_I			=> RST_O,
		CLK_I			=> CLK_O,

		-- JBUS Master signals
		CYC_O			=> CYC_I,
		STB_O			=> STB_I,
		WE_O			=> WE_I,
		SEL_O			=> SEL_I,
		ACK_I			=> ACK_O,
		SRDY_I			=> SRDY_O,
		MRDY_O			=> MRDY_I,
		ADDR_O			=> ADDR_I,
		MDAT_I			=> MDAT_O,
		MDAT_O			=> MDAT_I,

		-- JBUS Slave signals
		INT_O			=> INT_O,
		CYC_I			=> CYC_O,
		STB_I			=> STB_O,
		WE_I			=> WE_O,
		SEL_I			=> SEL_O,
		ACK_O			=> ACK_I,
		SRDY_O			=> SRDY_I,
		MRDY_I			=> MRDY_O,
		ADDR_I			=> ADDR_O,
		SDAT_I			=> SDAT_O,
		SDAT_O			=> SDAT_I,
		
		-- VGA signals
		vga_clk_in		=> vga_clk,
		vga_clk_ce		=> vga_en,
		vga_red			=> vga_red,
		vga_green		=> vga_green,
		vga_blue		=> vga_blue,
		vga_blank_n		=> vga_blank_n,
		vga_sync_n		=> vga_sync_n,
		vga_hsync		=> vga_hsync,
		vga_vsync		=> vga_vsync
	);

	vga_en		<= not RST_O;

rdy_GEN: process
	begin
		wait for 3*CLK_PERIOD/2;
		wait until rising_edge(CLK_O);
		rdy <= not rdy;
	end process;

CLK_GEN: process
	begin
		wait for CLK_PERIOD/2;
		CLK_O <= not CLK_O;
	end process;

VGA_CLK_GEN: process
	begin
		wait for VGA_CLK_PERIOD/2;
		vga_clk <= not vga_clk after 3 ns;
	end process;

-- Slave
	SRDY_O	<= CYC_I and rdy;
	
	process(CLK_O)
	variable ack_v : unsigned(11 downto 0);
	type arr64_t is array (11 downto 0) of unsigned(63 downto 0);
	variable dat_v : arr64_t;
	variable res: unsigned(63 downto 0);
	variable scan_count: unsigned(31 downto 0);
	variable blit_count: unsigned(31 downto 0);
	begin
		if rising_edge(CLK_O) then
			if RST_O = '1' then
				scan_count	:= X"00000000";
				blit_count	:= X"00000000";
				for i in 0 to 11 loop
					dat_v(i)	:= X"FFFFFFFF_FFFFFFFF";
					ack_v(i)	:= '0';
				end loop;
			else
				if (CYC_I and STB_I) = '1' and rdy = '1' and WE_I = '0' then
					if ADDR_I(24) = '0' then
						res			:= ADDR_I & scan_count;
						scan_count 	:= scan_count + 8;
					else
						res			:= ADDR_I & blit_count;
						blit_count 	:= blit_count + 8;
					end if;
					dat_v		:= dat_v(10 downto 0) & res;
					ack_v		:= ack_v(10 downto 0) & '1';
				else
					dat_v	:= dat_v(10 downto 0) & X"FFFFFFFF_FFFFFFFF";
					ack_v	:= ack_v(10 downto 0) & '0';
				end if;
				MDAT_O	<= dat_v(dat_v'left);
				ACK_O	<= ack_v(ack_v'left);
			end if;
		end if;
	end process;

	process(CLK_O)
	begin
		if rising_edge(CLK_O) then
			if RST_O = '1' then
				read_reg	<= X"00000000";
			elsif ACK_I = '1' then
				read_reg	<= SDAT_I;
			end if;
		end if;
	end process;

-- Master
STIMULUS: process

	begin

		wait for 6*CLK_PERIOD;
		RST_O <= '0';
		wait for 60*CLK_PERIOD;

		-- Enable master
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '1';
		SDAT_O	<= X"0000_0002";
		ADDR_O	<= X"0000_0000";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Read status
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_0000";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Read resolution
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_0014";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Read Cursor X
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_0008";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Read Cursor Y
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_000C";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Write char 1
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '1';
		SDAT_O	<= X"0000_0035";
		ADDR_O	<= X"0000_0004";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';
		
		-- Read char 1
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_0004";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';
		
		-- Write char 2
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '1';
		SDAT_O	<= X"0000_0045";
		ADDR_O	<= X"0000_0004";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Read char 2
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_0004";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';
		
		-- Read Cursor X
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_0008";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Read Cursor Y
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_000C";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Set Cursor X
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '1';
		SDAT_O	<= X"0000_0012";
		ADDR_O	<= X"0000_0008";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';
		
		-- Set Cursor Y
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '1';
		SDAT_O	<= X"0000_0014";
		ADDR_O	<= X"0000_000C";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';
		
		-- Read Cursor X
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_0008";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		-- Read Cursor Y
		CYC_O	<= '1';
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '1';
		WE_O	<= '0';
		ADDR_O	<= X"0000_000C";
		wait until rising_edge(CLK_O) and SRDY_I = '1';
		STB_O	<= '0';

		wait until rising_edge(CLK_O);
		CYC_O	<= '0';

		wait for 60000*CLK_PERIOD;

		for i in 0 to 99 loop
		
			-- BLIT test
			-- Read status
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '0';
			ADDR_O	<= X"0000_0000";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			wait until rising_edge(CLK_O) and ACK_I = '1';
			-- set src addr first
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= X"4100_0000";
			ADDR_O	<= X"0000_0020";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			-- set src addr last
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= X"4100_0000" + to_unsigned(4*(80*4-1), 32);
			ADDR_O	<= X"0000_0024";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			-- set src dim-x
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= to_unsigned(4*80, 32);
			ADDR_O	<= X"0000_0028";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			-- set dst addr first
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= X"4200_0000";
			ADDR_O	<= X"0000_0050";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			-- set dst addr last
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= X"4200_0000" + to_unsigned(4*(80*4-1), 32);
			ADDR_O	<= X"0000_0054";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			-- set dst dim-x
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= to_unsigned(4*80, 32);
			ADDR_O	<= X"0000_0058";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			-- set nx
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= to_unsigned(80-1, 32);
			ADDR_O	<= X"0000_0060";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			-- set ny
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= X"0000_0003";
			ADDR_O	<= X"0000_0064";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			-- set blit request
			CYC_O	<= '1';
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '1';
			WE_O	<= '1';
			SDAT_O	<= read_reg or X"0000_0100";
			ADDR_O	<= X"0000_0000";
			wait until rising_edge(CLK_O) and SRDY_I = '1';
			STB_O	<= '0';
			CYC_O	<= '0';
			WE_O	<= '0';
			
			wait for 100000*CLK_PERIOD;

		
		end loop;
		
		wait; 
	
	end process;
	
END;