Subversion Repositories avuc

-- File generated by avuc.pl (8/8/2009)

--

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

-- Copyright 2008 by USM

-- Description: Search for the maximum number in a memory.

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

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_unsigned.all;

library work;

use work.usm_pkg.all;

entity max_mem is

   port (

      -- To start the program:

      avuc_start: in std_logic;

      -- To stop the program:

      avuc_rst: in std_logic;

      -- Main clock:

      clk: in std_logic;

      -- Memory data bus:

      mem_data: in std_logic_vector(7 downto 0);

      -- Memory address bus:

      mem_addr: out std_logic_vector(6 downto 0);

      -- State of the program (running/stopped):

      avuc_state: out std_logic

   );

end max_mem;

architecture program of max_mem is

-- Temporary maximum number 

signal max_number: std_logic_vector(mem_data'range);

-- Copy of output:

signal mem_addr_s: std_logic_vector(mem_addr'range);

-- Basic registers of usm:

signal usm_opcode: std_logic_vector(2 downto 0);

signal usm_pc: std_logic_vector(2 downto 0) := (others => '1');

signal usm_data: std_logic_vector(2 downto 0);

signal usm_cyclesno: std_logic_vector(0 downto 0);

-- Cycles counter:

signal usm_cy: std_logic_vector(1 downto 0);

-- usm_cy(0) delayed 1 clock:

signal usm_cy_0_d1: std_logic;

-- To avoid usm_cy deadlock:

signal usm_cy_rst: std_logic;

-- Commands list:

constant USMO_NOP:

         std_logic_vector(usm_opcode'range) := "000";

constant USMO_JUMP:

         std_logic_vector(usm_opcode'range) := "001";

constant USMO_MEM_ADDR_INI:

         std_logic_vector(usm_opcode'range) := "010";

constant USMO_MEM_ADDR_INC:

         std_logic_vector(usm_opcode'range) := "011";

constant USMO_MAX_NUMBER_INI:

         std_logic_vector(usm_opcode'range) := "100";

constant USMO_MAX_NUMBER_ASSIGN:

         std_logic_vector(usm_opcode'range) := "101";

constant USMO_JUMP_IF_MEM_ADDR_EQ_LAST:

         std_logic_vector(usm_opcode'range) := "110";

constant USMO_JUMP_IF_MEM_DATA_LT_MAX:

         std_logic_vector(usm_opcode'range) := "111";

-- Labels list:

constant USML_NEXT1:

         std_logic_vector(usm_pc'range) := "100";

constant USML_LOOP1:

         std_logic_vector(usm_pc'range) := "010";

constant USML_BEGIN:

         std_logic_vector(usm_pc'range) := "000";

constant USML_END:

         std_logic_vector(usm_pc'range) := "111";

-- usm_pc reset:

signal avuc_start_d: std_logic_vector(2 downto 0);

signal avuc_rst_d: std_logic_vector(2 downto 0);

signal stup_rst, stup_rst_d1: std_logic;

signal stup_rst_cnt: std_logic_vector(5 downto 0) := (others => '0');

signal usm_pc_gt_end: std_logic;

signal usm_pc_ldini_init_d1: std_logic;

signal usm_pc_ldend_init_d1: std_logic;

-- usm_pc microcodes:

signal usm_pc_inc: std_logic;

signal usm_pc_ldjmp: std_logic;

signal usm_pc_ldini: std_logic;

signal usm_pc_ldend: std_logic;

-- Remaining microcodes:

signal usm_max_number_assign_0: std_logic;

signal usm_max_number_ini_0: std_logic;

signal usm_mem_addr_ini_0: std_logic;

signal usm_mem_addr_inc_0: std_logic;

begin

--***************************** Program processes *****************************--

-- Program start/stop/state:

p_prog_init: process(clk)

variable usm_pc_ld_init_var: std_logic;

begin

   if rising_edge(clk) then

      -- Program start:

      avuc_start_d(0) <= avuc_start;

      avuc_start_d(1) <= avuc_start_d(0);

      avuc_start_d(2) <= avuc_start_d(1);

      usm_pc_ld_init_var := avuc_start_d(1) and not avuc_start_d(2);

      usm_pc_ldini_init_d1 <= usm_pc_ld_init_var;

      usm_pc_ldini <= usm_pc_ld_init_var or usm_pc_ldini_init_d1;          -- 2 clocks long

      -- Program stop:

      if stup_rst = '1' then

         stup_rst_cnt <= stup_rst_cnt + 1;

      end if;

      stup_rst <= '0';

      if stup_rst_cnt(5 downto 4) /= 2 then

         stup_rst <= '1';

      end if;

      stup_rst_d1 <= stup_rst;

      usm_pc_gt_end <= '0';

      if usm_pc > USML_END and usm_pc_gt_end = '0' then

         usm_pc_gt_end <= '1';

      end if;

      avuc_rst_d(0) <= avuc_rst;

      avuc_rst_d(1) <= avuc_rst_d(0);

      avuc_rst_d(2) <= avuc_rst_d(1);

      usm_pc_ld_init_var := usm_pc_gt_end or (not stup_rst and stup_rst_d1) or

                                             ( avuc_rst_d(1) and not avuc_rst_d(2) );

      usm_pc_ldend_init_d1 <= usm_pc_ld_init_var;

      usm_pc_ldend <= usm_pc_ld_init_var or usm_pc_ldend_init_d1;          -- 2 clocks long

      -- Program state:

      avuc_state <= AVUC_STATE_RUNNING;

      if usm_pc = USML_END then

         avuc_state <= AVUC_STATE_STOPPED;

      end if;

   end if;

end process p_prog_init;

p_usm_prog_code: process(usm_pc)

begin

   usm_data <= (others => '-');

   case usm_pc is

   when "000" =>

      usm_opcode <= USMO_MEM_ADDR_INI;

      usm_cyclesno <= (0 => '1', others => '0');

   when "001" =>

      usm_opcode <= USMO_MAX_NUMBER_INI;

      usm_cyclesno <= (0 => '1', others => '0');

   when "010" =>

      usm_opcode <= USMO_JUMP_IF_MEM_DATA_LT_MAX;

      usm_cyclesno <= (0 => '1', others => '0');

      usm_data <= "100";

   when "011" =>

      usm_opcode <= USMO_MAX_NUMBER_ASSIGN;

      usm_cyclesno <= (0 => '1', others => '0');

   when "100" =>

      usm_opcode <= USMO_JUMP_IF_MEM_ADDR_EQ_LAST;

      usm_cyclesno <= (0 => '1', others => '0');

      usm_data <= "111";

   when "101" =>

      usm_opcode <= USMO_MEM_ADDR_INC;

      usm_cyclesno <= (0 => '1', others => '0');

   when "110" =>

      usm_opcode <= USMO_JUMP;

      usm_cyclesno <= (0 => '1', others => '0');

      usm_data <= "010";

   when "111" =>

      usm_opcode <= USMO_JUMP;

      usm_cyclesno <= (0 => '1', others => '0');

      usm_data <= "111";

   when others =>

      usm_opcode <= (others => '-');

      usm_cyclesno <= (others => '-');

   end case;

end process p_usm_prog_code;

--************************** Jump & cycle processes ***************************--

p_usm_pc_drv: process(clk)

variable var_aux: std_logic_vector(3 downto 0);

begin

   if rising_edge(clk) then

      -- usm_pc_inc (increment usm_pc):

      usm_pc_inc <= '0';

      if usm_cy = usm_cyclesno and usm_pc_ldini_init_d1 = '0' then

         usm_pc_inc <= '1';

      end if;

      -- usm_pc_ldjmp (load usm_pc with usm_data):

      usm_pc_ldjmp <= '0';

      case usm_opcode is

      when USMO_JUMP =>

         usm_pc_ldjmp <= '1';

      when USMO_JUMP_IF_MEM_ADDR_EQ_LAST =>

         if mem_addr_s = (mem_addr_s'range => '1')

 then

            usm_pc_ldjmp <= '1';

         end if;

      when USMO_JUMP_IF_MEM_DATA_LT_MAX =>

         if mem_data < max_number

   then

            usm_pc_ldjmp <= '1';

         end if;

      when others =>

         usm_pc_ldjmp <= '0';

      end case;

      -- usm_pc:

      usm_cy_0_d1 <= usm_cy(0) and not usm_pc_ldini_init_d1;

      var_aux := usm_pc_ldini & usm_pc_ldend & (usm_pc_ldjmp and usm_cy_0_d1) & usm_pc_inc;

      case var_aux is

      when "0000" =>

         null;

      when "0001" =>

         usm_pc <= usm_pc + 1;

      when "0010" | "0011" =>

         usm_pc <= usm_data(usm_pc'range);

      when "0100" | "0101" | "0110" | "0111" =>

         usm_pc <= USML_END;

      when "1000" | "1001" | "1010" | "1011" | "1100" | "1101" | "1110" | "1111" =>       -- 1XXX

         usm_pc <= USML_BEGIN;

      when others =>

            null;

--          usm_pc <= USML_BEGIN;

      end case;

   end if;

end process p_usm_pc_drv;

p_usm_cy_drv: process(clk)

begin

   if rising_edge(clk) then

      usm_cy_rst <= '0';

      if usm_cy = 0 then

         usm_cy_rst <= '1';

      end if;

      -- usm_cy:

      if usm_pc_inc = '1' or (usm_pc_ldjmp = '1' and usm_cy_0_d1 = '1') or

                                    usm_pc_ldini_init_d1 = '1' or usm_cy_rst = '1' then

         usm_cy <= (0 => '1', others => '0');

      else

         usm_cy(0) <= '0';

         for i in usm_cy'range loop

            if i /= 0 then

               usm_cy(i) <= usm_cy(i-1);

            end if;

         end loop;

      end if;

   end if;

end process p_usm_cy_drv;

--**************************** Drivers processes ******************************--

p_usm_max_number_drv: process(clk)

variable max_number_var: std_logic_vector(1 downto 0);

begin

   if rising_edge(clk) then

      -- max_number_assign:

      usm_max_number_assign_0 <= '0';

      if usm_opcode = USMO_MAX_NUMBER_ASSIGN then

         if usm_cy(0) = '1' then

            usm_max_number_assign_0 <= '1';

         end if;

      end if;

      -- max_number_ini:

      usm_max_number_ini_0 <= '0';

      if usm_opcode = USMO_MAX_NUMBER_INI then

         if usm_cy(0) = '1' then

            usm_max_number_ini_0 <= '1';

         end if;

      end if;

      -- Actions:

      max_number_var := usm_max_number_assign_0 & usm_max_number_ini_0;

      case max_number_var is

      when "00" => null;

      when "10" =>

         max_number <= mem_data;

      when "01" =>

         max_number <= (others => '0');

      when others => null;

      end case;

   end if;

end process p_usm_max_number_drv;

p_usm_mem_addr_s_drv: process(clk)

variable mem_addr_s_var: std_logic_vector(1 downto 0);

begin

   if rising_edge(clk) then

      -- mem_addr_ini:

      usm_mem_addr_ini_0 <= '0';

      if usm_opcode = USMO_MEM_ADDR_INI then

         if usm_cy(0) = '1' then

            usm_mem_addr_ini_0 <= '1';

         end if;

      end if;

      -- mem_addr_inc:

      usm_mem_addr_inc_0 <= '0';

      if usm_opcode = USMO_MEM_ADDR_INC then

         if usm_cy(0) = '1' then

            usm_mem_addr_inc_0 <= '1';

         end if;

      end if;

      -- Actions:

      mem_addr_s_var := usm_mem_addr_inc_0 & usm_mem_addr_ini_0;

      case mem_addr_s_var is

      when "00" => null;

      when "10" =>

         mem_addr_s <= mem_addr_s + 1;

      when "01" =>

         mem_addr_s <= (others => '0');

      when others => null;

      end case;

   end if;

end process p_usm_mem_addr_s_drv;

--******************************** Extra code *********************************--

   mem_addr <= mem_addr_s;

end program;