ir_decoder_spec.vhd

這是Originl公司出的8051 VHDL source code.

--------------------------------------------------
-- Model        :   8051 Behavioral Model,
--                  VHDL Entity mc8051.ir_decoder.interface
--
-- Author       :   Michael Mayer ([e-mail]),
--                  Dr. Hardy J. Pottinger,
--                  Department of Electrical Engineering
--                  University of Missouri - Rolla
--
-- Created at   :   09/19/98 20:02:06
--
LIBRARY ieee ;
USE ieee.std_logic_1164.all;
USE ieee.numeric_std.all;
LIBRARY mc8051 ;
USE mc8051.cpu_pack.all;
USE mc8051.synth_pack.all;

ENTITY ir_decoder IS
   PORT( 
      alu_second_result : IN     std_logic ;
      cpu_rst : IN     std_logic ;
      cy : IN     std_logic ;
      int_clk : IN     std_logic ;
      ir : IN     std_logic_vector( 7 DOWNTO 0 )  ;
      new_ir : IN     std_logic ;
      alu_cmd : OUT    std_logic_vector( 3 DOWNTO 0 )  ;
      data_alu : OUT    std_logic_vector( 2 DOWNTO 0 )  ;
      data_dest : OUT    std_logic_vector( 2 DOWNTO 0 )  ;
      data_t1 : OUT    std_logic_vector( 2 DOWNTO 0 )  ;
      data_t2 : OUT    std_logic_vector( 2 DOWNTO 0 )  ;
      dest_cmd : OUT    std_logic_vector( 3 DOWNTO 0 )  ;
      read_latch : OUT    std_logic ;
      set_ac_ov : OUT    std_logic ;
      set_cy : OUT    std_logic ;
      t1_cmd : OUT    std_logic_vector( 3 DOWNTO 0 )  ;
      t2_cmd : OUT    std_logic_vector( 3 DOWNTO 0 )  ;
      two_dests : OUT    std_logic ;
      use_acc_0 : OUT    std_logic ;
      use_cy : OUT    std_logic
   );

-- Declarations

END ir_decoder ;
--
-- VHDL Architecture mc8051.ir_decoder.spec
--
-- Created:
--          by - mrmayer.UNKNOWN (eceultra20.ece.umr.edu)
--          at - 23:24:26 09/02/98
--
-- Generated by Mentor Graphics' Renoir(TM) 3.0 (Build 110)
--
architecture spec of ir_decoder is

   SIGNAL cy_int : std_logic;
   SIGNAL ir_10  : bit_vector(7 DOWNTO 0);
BEGIN

--t1, t2, alu, and dest each get 4 bits of cmd + 3 bits of data.
--this means we need a 8bit (opcode) to 16 bit (4x4 cmds) converter
--and then driver for the 12 bits (4x3) of data

-- latch with new_ir
cy_int    <= cy WHEN new_ir = '1' ELSE cy_int;
ir_10     <= To_bitvector (ir);
read_latch <= '0';   -- ALL ARE CONSIDERED READ PINS!!!

p1 : PROCESS (int_clk) IS
BEGIN

two_dests <= '0';
CASE ir_10 IS
  WHEN "00000000" | "10100101" => --NOP, reserved
       t1_cmd      <= zeros;       data_t1 <= "000";
       t2_cmd      <= zeros;       data_t2 <= "000";
       alu_cmd     <= pass_tmp1;
       dest_cmd    <= nothing;

  WHEN "00000001" | "00100001" | "01000001" | "01100001" | 
       "10000001" | "10100001" | "11000001" | "11100001" |    --  AJMP
       "00010001" | "00110001" | "01010001" | "01110001" | 
       "10010001" | "10110001" | "11010001" | "11110001" |    --  ACALL
       "00000010" | "00010010" | "00100010" | "00110010" =>   --  LJMP, LCALL, RET, RETI
           t1_cmd      <= nothing; 
           t2_cmd      <= nothing;
           alu_cmd     <= pass_tmp1;
           data_alu    <= "000";
           dest_cmd    <= nothing;   -- pass result to data_gb

  WHEN "11000000" =>   --  PUSH C0
       t1_cmd      <= direct_T;      data_t1 <= "001"; 
       t2_cmd      <= zeros; 
       alu_cmd     <= pass_tmp1; 
       dest_cmd    <= wr_at_sp; 

  WHEN "11010000" =>   --  POP D0
       t1_cmd      <= rd_at_sp; 
       t2_cmd      <= zeros; 
       alu_cmd     <= pass_tmp1;   data_alu    <= "000";
       dest_cmd    <= direct_T;      data_dest <= "001"; 

  WHEN "00000011" =>   -- RR (03) 
       t1_cmd      <= nothing;
       t2_cmd      <= use_acc;
       alu_cmd     <= rotate;   data_alu <= rr_instr; 
       use_cy      <= '0';
       dest_cmd    <= use_acc;

  WHEN "00010011" =>   -- RRC (13)
       t1_cmd      <= nothing;
       t2_cmd      <= use_acc;
       alu_cmd     <= rotate;   data_alu <= rr_instr;
       use_cy      <= '1';
       dest_cmd    <= use_acc;

  WHEN "00100011" =>   -- RL (23)
       t1_cmd      <= nothing;
       t2_cmd      <= use_acc;
       alu_cmd     <= rotate;   data_alu <= rl_instr;
       use_cy      <= '0';
       dest_cmd    <= use_acc;

  WHEN "00110011" =>   --  RLC (33)
       t1_cmd      <= nothing;
       t2_cmd      <= use_acc;
       alu_cmd     <= rotate;   data_alu <= rl_instr;
       use_cy      <= '1';
       dest_cmd    <= use_acc;

  WHEN "00000100" =>   --  INC A "04"  
       t1_cmd      <= use_acc;
       t2_cmd      <= nothing;
       alu_cmd     <= pass_tmp1;  data_alu <= t1_inc; 
       dest_cmd    <= use_acc; 

  WHEN "00000101" =>   --   INC direct_T "05"
       t1_cmd      <= direct_T;     data_t1 <= "001";   -- use byte 1
       t2_cmd      <= nothing;
       alu_cmd     <= pass_tmp1;  data_alu <= t1_inc; 
       --dest_cmd    <= direct_T;     data_dest <= "001";
       dest_cmd    <= same_as_t1;
       read_latch  <= '1';

  WHEN "00000110" | "00000111" =>   --   INC @Ri "06" - "07"
       t1_cmd      <= indirect_T;   data_t1 <= "00"&ir(0);
       t2_cmd      <= nothing; 
       alu_cmd     <= pass_tmp1;  data_alu <= t1_inc; 
       --dest_cmd    <= indirect_T;   data_dest <= "00"&ir(0);
       dest_cmd    <= same_as_t1;
       read_latch  <= '1';

  WHEN "00001000" | "00001001" | "00001010" | "00001011" |
       "00001100" | "00001101" | "00001110" | "00001111" =>   
       --  INC Rn 08-0F
       t1_cmd      <= use_reg;    data_t1 <= ir(2 DOWNTO 0); 
       t2_cmd      <= nothing;
       alu_cmd     <= pass_tmp1;  data_alu <= t1_inc; 
       --dest_cmd    <= use_reg;    data_dest <= ir(2 DOWNTO 0);
       dest_cmd    <= same_as_t1;

  WHEN "00010100" =>   --  DEC A "14"
       t1_cmd      <= use_acc;
       t2_cmd      <= nothing; 
       alu_cmd     <= pass_tmp1;  data_alu <= t1_dec; 
       dest_cmd    <= use_acc; 

  WHEN "00010101" =>   --   DEC direct_T "15"
       t1_cmd      <= direct_T;     data_t2 <= "001";   -- use byte 1
       t2_cmd      <= nothing;
       alu_cmd     <= pass_tmp1;  data_alu <= t1_dec; 
       --dest_cmd    <= direct_T;     data_dest <= "001";
       dest_cmd    <= same_as_t1;
       read_latch  <= '1';

  WHEN "00010110" | "00010111" =>   --   DEC @Ri "16" - "17"
       t1_cmd      <= indirect_T;   data_t2 <= "00"&ir(0); 
       t2_cmd      <= nothing;
       alu_cmd     <= pass_tmp1;  data_alu <= t1_dec;
       --dest_cmd    <= indirect_T;   data_dest <= "00"&ir(0);
       dest_cmd    <= same_as_t1;
       read_latch  <= '1';

  WHEN "00011000" | "00011001" | "00011010" | "00011011" |
       "00011100" | "00011101" | "00011110" | "00011111" =>
       --  DEC Rn 18-1F
       t1_cmd      <= use_reg;    data_t2 <= ir(2 DOWNTO 0); 
       t2_cmd      <= nothing;
       alu_cmd     <= pass_tmp1;  data_alu <= t1_dec;
       --dest_cmd    <= use_reg;    data_dest <= ir(2 DOWNTO 0);
       dest_cmd    <= same_as_t1;

  WHEN "00100100" =>   --  ADD A,#data  "24"
       t1_cmd      <= immed;      data_t1 <= "001" ;
       t2_cmd      <= use_acc;
       alu_cmd     <= add_instr;  data_alu <= "000";
       set_cy <= '1';   set_ac_ov <= '1';
       dest_cmd    <= use_acc; 

  WHEN "00100101" =>   --   ADD A,direct_T "25"
       t1_cmd      <= direct_T;     data_t1 <= "001";   -- use byte 
       t2_cmd      <= use_acc; 
       alu_cmd     <= add_instr;  data_alu <= "000";
       set_cy <= '1';  set_ac_ov <= '1';
       dest_cmd    <= use_acc;

  WHEN "00100110" | "00100111" =>  --   ADD A,@Ri "26" - "27"
       t1_cmd      <= indirect_T;   data_t1 <= "00"&ir(0);
       t2_cmd      <= use_acc; 
       alu_cmd     <= add_instr;  data_alu <= "000";
       set_cy <= '1';  set_ac_ov <= '1';
       dest_cmd    <= use_acc;

  WHEN "00101000" | "00101001" | "00101010" | "00101011" |
       "00101100" | "00101101" | "00101110" | "00101111" =>
       --  ADD A,Rn 28-2F
       t1_cmd      <= use_reg;    data_t1 <= ir(2 DOWNTO 0);
       t2_cmd      <= use_acc; 
       alu_cmd     <= add_instr;  data_alu <= "000";
       set_cy <= '1';  set_ac_ov <= '1';
       dest_cmd    <= use_acc;

  WHEN "00110100" =>   --  ADDC #data "34"
       t1_cmd      <= immed;      data_t1 <= "001" ;
       t2_cmd      <= use_acc;
       alu_cmd     <= add_instr;
       IF cy_int = '1' THEN data_alu <= t1_inc;
       ELSE                 data_alu <= "000";
       END IF;
       set_cy <= '1';  set_ac_ov <= '1';
       dest_cmd    <= use_acc; 

  WHEN "00110101" =>   --   ADDC direct_T "35"
       t1_cmd      <= direct_T;    data_t1 <= "001";   -- use byte 
       t2_cmd      <= use_acc; 
       alu_cmd     <= add_instr;
       IF cy_int = '1' THEN data_alu <= t1_inc;
       ELSE                 data_alu <= "000";
       END IF;
       set_cy <= '1';  set_ac_ov <= '1';
       dest_cmd    <= use_acc;

  WHEN "00110110" | "00110111" =>   --   ADDC @Ri "36" - "37"
       t1_cmd      <= indirect_T;  data_t1 <= "00"&ir(0);
       t2_cmd      <= use_acc; 
       alu_cmd     <= add_instr;
       IF cy_int = '1' THEN data_alu <= t1_inc;
       ELSE                 data_alu <= "000";
       END IF;
       set_cy <= '1';  set_ac_ov <= '1';
       dest_cmd    <= use_acc;

  WHEN "00111000" | "00111001" | "00111010" | "00111011" |
       "00111100" | "00111101" | "00111110" | "00111111" =>
        --  ADDC Rn 38-3F
       t1_cmd      <= use_reg;   data_t1 <= ir(2 DOWNTO 0);
       t2_cmd      <= use_acc; 
       alu_cmd     <= add_instr;
       IF cy_int = '1' THEN data_alu <= t1_inc;
       ELSE                 data_alu <= "000";
       END IF;
       set_cy <= '1';  set_ac_ov <= '1';
       dest_cmd    <= use_acc;

  WHEN "01000010" =>   --  ORL direct_T,A "42"
       t1_cmd      <= direct_T;   data_t1 <= "001" ;
       t2_cmd      <= use_acc;
       alu_cmd     <= logic;   data_alu <= orl_instr;
       dest_cmd    <= same_as_t1; 
       read_latch  <= '1';

  WHEN "01000011" =>   --  ORL direct_T,#data "43"
       t1_cmd      <= immed;  data_t1 <= "010" ;
       t2_cmd      <= direct_T;  data_t1 <= "001";  
       alu_cmd     <= logic;   data_alu <= orl_instr;
       dest_cmd    <= same_as_t1; 
       read_latch  <= '1';

  WHEN "01000100" =>   --  ORL A, #data "44"
       t1_cmd      <= immed;  data_t1 <= "001" ;
       t2_cmd      <= use_acc;
       alu_cmd     <= logic;   data_alu <= orl_instr;
       dest_cmd    <= use_acc; 

  WHEN "01000101" =>   --  ORL A,direct_T "45"
       t1_cmd      <= direct_T; data_t1 <= "001";   -- use byte 
       t2_cmd      <= use_acc; 
       alu_cmd     <= logic;   data_alu <= orl_instr;
       dest_cmd    <= use_acc;