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-- $Id: pdp11_ubmap.vhd 335 2010-10-24 22:24:23Z mueller $

--

-- Copyright 2008-2010 by Walter F.J. Mueller <W.F.J.Mueller@gsi.de>

--

-- This program is free software; you may redistribute and/or modify it under

-- the terms of the GNU General Public License as published by the Free

-- Software Foundation, either version 2, or at your option any later version.

--

-- This program 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 General Public License

-- for complete details.

--

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

-- Module Name:    pdp11_ubmap - syn

-- Description:    pdp11: 11/70 unibus mapper

--

-- Dependencies:   memlib/ram_1swar_gen

--                 ib_sel

-- Test bench:     tb/tb_pdp11_core (implicit)

-- Target Devices: generic

-- Tool versions:  xst 8.1, 8.2, 9.1, 9.2, 12.1; ghdl 0.18-0.29

--

-- Revision History: 

-- Date         Rev Version  Comment

-- 2010-10-23   335   1.1.1  use ib_sel

-- 2010-10-17   333   1.1    use ibus V2 interface

-- 2008-08-22   161   1.0.1  use iblib

-- 2008-01-27   115   1.0    Initial version 

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

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_arith.all;

use work.slvtypes.all;

use work.memlib.all;

use work.iblib.all;

use work.pdp11.all;

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

entity pdp11_ubmap is                   -- 11/70 unibus mapper

  port (

    CLK : in slbit;                     -- clock

    MREQ : in slbit;                    -- request mapping

    ADDR_UB : in slv18_1;               -- UNIBUS address (in)

    ADDR_PM : out slv22_1;              -- physical memory address (out)

    IB_MREQ : in ib_mreq_type;          -- ibus request

    IB_SRES : out ib_sres_type          -- ibus response

  );

end pdp11_ubmap;

architecture syn of pdp11_ubmap is

  constant ibaddr_ubmap : slv16 := conv_std_logic_vector(8#170200#,16);

  signal IBSEL_UBMAP : slbit := '0';

  signal MAP_2_WE : slbit := '0';

  signal MAP_1_WE : slbit := '0';

  signal MAP_0_WE : slbit := '0';

  signal MAP_ADDR : slv5 := (others => '0');     -- map regs address

  signal MAP_DOUT : slv22_1 := (others => '0');  -- map regs output

begin

  MAP_2 : ram_1swar_gen                 -- bit 21:16 of map regs

    generic map (

      AWIDTH => 5,

      DWIDTH => 6)

    port map (

      CLK  => CLK,

      WE   => MAP_2_WE,

      ADDR => MAP_ADDR,

      DI   => IB_MREQ.din(5 downto 0),

      DO   => MAP_DOUT(21 downto 16));

  MAP_1 : ram_1swar_gen                 -- bit 15:08 of map regs

    generic map (

      AWIDTH => 5,

      DWIDTH => 8)

    port map (

      CLK  => CLK,

      WE   => MAP_1_WE,

      ADDR => MAP_ADDR,

      DI   => IB_MREQ.din(15 downto 8),

      DO   => MAP_DOUT(15 downto 8));

  MAP_0 : ram_1swar_gen                 -- bit 07:01 of map regs

    generic map (

      AWIDTH => 5,

      DWIDTH => 7)

    port map (

      CLK  => CLK,

      WE   => MAP_0_WE,

      ADDR => MAP_ADDR,

      DI   => IB_MREQ.din(7 downto 1),

      DO   => MAP_DOUT(7 downto 1));

  SEL : ib_sel

    generic map (

      IB_ADDR => ibaddr_ubmap,

      SAWIDTH => 6)                     -- 2^6 = 64 = 2*32 words

    port map (

      CLK     => CLK,

      IB_MREQ => IB_MREQ,

      SEL     => IBSEL_UBMAP

    );

  proc_comb: process (MREQ, ADDR_UB, IBSEL_UBMAP, IB_MREQ, MAP_DOUT)

    variable ibusy : slbit := '0';

    variable idout : slv16 := (others=>'0');

    variable iwe2  : slbit := '0';

    variable iwe1  : slbit := '0';

    variable iwe0  : slbit := '0';

    variable iaddr : slv5 := (others=>'0');

  begin

    ibusy := '0';

    idout := (others=>'0');

    iwe2  := '0';

    iwe1  := '0';

    iwe0  := '0';

    iaddr := (others=>'0');

    if IBSEL_UBMAP = '1' then

      if IB_MREQ.addr(1) = '1' then

        idout(5 downto 0)  := MAP_DOUT(21 downto 16);

      else

        idout(15 downto 1) := MAP_DOUT(15 downto 1);

      end if;

      if MREQ = '1' then                -- if map request, stall ib cycle

        ibusy := '1';

      end if;

    end if;

    if IBSEL_UBMAP='1' and IB_MREQ.we='1' then

      if IB_MREQ.addr(1)='1' then

        if IB_MREQ.be0 = '1' then

          iwe2 := '1';

        end if;

      else

        if IB_MREQ.be1 = '1' then

          iwe1 := '1';

        end if;

        if IB_MREQ.be0 = '1' then

          iwe0 := '1';

        end if;

      end if;

    end if;

    if MREQ = '1' then

      iaddr := ADDR_UB(17 downto 13);

    else

      iaddr := IB_MREQ.addr(6 downto 2);

    end if;

    MAP_ADDR <= iaddr;

    MAP_2_WE <= iwe2;

    MAP_1_WE <= iwe1;

    MAP_0_WE <= iwe0;

    ADDR_PM  <= unsigned(MAP_DOUT) + unsigned("000000000"&ADDR_UB(12 downto 1));

    IB_SRES.ack  <= IBSEL_UBMAP and (IB_MREQ.re or IB_MREQ.we);

    IB_SRES.busy <= ibusy;

    IB_SRES.dout <= idout;

  end process proc_comb;

end syn;