--------------------------------------------------------------------------------  This file is a part of the GRLIB VHDL IP LIBRARY--  Copyright (C) 2003, Gaisler Research----  This program is free software; you can redistribute it and/or modify--  it under the terms of the GNU General Public License as published by--  the Free Software Foundation; either version 2 of the License, 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 more details.----  You should have received a copy of the GNU General Public License--  along with this program; if not, write to the Free Software--  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA ------------------------------------------------------------------------------- Entity: 	mmutlbcam-- File:	mmutlbcam.vhd-- Author:	Konrad Eisele, Jiri Gaisler, Gaisler Research-- Description:	MMU TLB logic------------------------------------------------------------------------------library ieee;use ieee.std_logic_1164.all;library grlib;use grlib.amba.all;use grlib.stdlib.all;library gaisler;use gaisler.libiu.all;use gaisler.libcache.all;use gaisler.leon3.all;use gaisler.mmuconfig.all;use gaisler.mmuiface.all;entity mmutlbcam is    generic (     tlb_type  : integer range 0 to 3 := 1  );  port (      rst     : in std_logic;      clk     : in std_logic;      tlbcami : in mmutlbcam_in_type;      tlbcamo : out mmutlbcam_out_type  );end mmutlbcam;architecture rtl of mmutlbcam is    constant M_TLB_FASTWRITE : integer range 0 to 3 := conv_integer(conv_std_logic_vector(tlb_type,2) and conv_std_logic_vector(2,2));   -- fast writebuffer  type tlbcam_rtype is record    btag     : tlbcam_reg;  end record;  signal r,c : tlbcam_rtype;begin    p0: process (rst, r, tlbcami)  variable v : tlbcam_rtype;  variable hm, hf                : std_logic;  variable h_i1, h_i2, h_i3, h_c : std_logic;  variable h_l2, h_l3            : std_logic;  variable h_su_cnt              : std_logic;  variable blvl                  : std_logic_vector(1 downto 0);  variable bet                   : std_logic_vector(1 downto 0);  variable bsu                   : std_logic;  variable blvl_decode           : std_logic_vector(3 downto 0);  variable bet_decode            : std_logic_vector(3 downto 0);  variable ref, modified         : std_logic;  variable tlbcamo_pteout        : std_logic_vector(31 downto 0);  variable tlbcamo_LVL           : std_logic_vector(1 downto 0);  variable tlbcamo_NEEDSYNC      : std_logic;  variable tlbcamo_WBNEEDSYNC    : std_logic;  begin    v := r;    --#init    h_i1 := '0'; h_i2 := '0'; h_i3 := '0'; h_c := '0';    hm := '0';    hf := r.btag.VALID;        blvl := r.btag.LVL;    bet  := r.btag.ET;    bsu  := r.btag.SU;    bet_decode  := decode(bet);    blvl_decode  := decode(blvl);    ref := r.btag.R;    modified := r.btag.M;    tlbcamo_pteout := (others => '0');    tlbcamo_lvl := (others => '0');         -- prepare tag comparision    if (r.btag.I1  = tlbcami.tagin.I1)  then h_i1 := '1';  else h_i1 := '0'; end if;    if (r.btag.I2  = tlbcami.tagin.I2)  then h_i2 := '1';  else h_i2 := '0'; end if;    if (r.btag.I3  = tlbcami.tagin.I3)  then h_i3 := '1';  else h_i3 := '0'; end if;    if (r.btag.CTX = tlbcami.tagin.CTX) then h_c  := '1';  else h_c  := '0'; end if;        -- #level 2 hit (segment)    h_l2 := h_i1 and h_i2 ;    -- #level 3 hit (page)    h_l3 := h_i1 and h_i2 and h_i3;    -- # context + su    h_su_cnt := h_c or bsu;        --# translation (match) op    case blvl is      when LVL_PAGE    => hm := h_l3 and h_c and r.btag.VALID;      when LVL_SEGMENT => hm := h_l2 and h_c and r.btag.VALID;      when LVL_REGION  => hm := h_i1 and h_c and r.btag.VALID;      when LVL_CTX     => hm :=          h_c and r.btag.VALID;      when others      => hm := 'X';    end case;        --# translation: update ref/mod bit    tlbcamo_NEEDSYNC := '0';    if (tlbcami.trans_op and hm  ) = '1' then      v.btag.R := '1';      v.btag.M := r.btag.M or tlbcami.tagin.M;      tlbcamo_NEEDSYNC := (not r.btag.R) or (tlbcami.tagin.M and (not r.btag.M));  -- cam: ref/modified changed, write back synchronously    end if;    tlbcamo_WBNEEDSYNC := '0';    if ( hm  ) = '1' then      tlbcamo_WBNEEDSYNC := (not r.btag.R) or (tlbcami.tagin.M and (not r.btag.M));  -- cam: ref/modified changed, write back synchronously    end if;        --# flush operation    -- tlbcam only stores PTEs, tlb does not store PTDs    case tlbcami.tagin.TYP is                              when FPTY_PAGE =>                        -- page        hf := hf and h_su_cnt and h_l3 and (blvl_decode(0));  -- only level 3 (page)      when FPTY_SEGMENT =>                     -- segment        hf := hf and h_su_cnt and h_l2 and (blvl_decode(0) or blvl_decode(1));  -- only level 2+3 (segment,page)      when FPTY_REGION =>                      -- region        hf := hf and h_su_cnt and h_i1 and (not blvl_decode(3));  -- only level 1+2+3 (region,segment,page)      when FPTY_CTX =>                         -- context        hf := hf and (h_c and (not bsu));       when FPTY_N  =>                          -- entire      when others =>        hf := '0';    end case;        --# flush: invalidate on flush hit    --if (tlbcami.flush_op and hf ) = '1' then    if (tlbcami.flush_op  ) = '1' then      v.btag.VALID := '0';    end if;        --# write op    if ( tlbcami.write_op  = '1' ) then      v.btag := tlbcami.tagwrite;    end if;    --# reset    if (rst = '0' or tlbcami.mmuen = '0') then      v.btag.VALID := '0';    end if;        tlbcamo_pteout(PTE_PPN_U downto PTE_PPN_D) := r.btag.PPN;    tlbcamo_pteout(PTE_C) := r.btag.C;    tlbcamo_pteout(PTE_M) := r.btag.M;    tlbcamo_pteout(PTE_R) := r.btag.R;    tlbcamo_pteout(PTE_ACC_U downto PTE_ACC_D) := r.btag.ACC;    tlbcamo_pteout(PT_ET_U downto PT_ET_D) := r.btag.ET;    tlbcamo_LVL(1 downto 0) := r.btag.LVL;        --# drive signals    tlbcamo.pteout   <= tlbcamo_pteout;    tlbcamo.LVL      <= tlbcamo_LVL;    --tlbcamo.hit      <= (tlbcami.trans_op and hm) or (tlbcami.flush_op and hf);    tlbcamo.hit      <= (hm) or (tlbcami.flush_op and hf);    tlbcamo.ctx      <= r.btag.CTX;       -- for diagnostic only    tlbcamo.valid    <= r.btag.VALID;     -- for diagnostic only    tlbcamo.vaddr    <= r.btag.I1 & r.btag.I2 & r.btag.I3 & "000000000000"; -- for diagnostic only    tlbcamo.NEEDSYNC <= tlbcamo_NEEDSYNC;    tlbcamo.WBNEEDSYNC <= tlbcamo_WBNEEDSYNC;            c <= v;  end process p0;    p1: process (clk, c)  begin if rising_edge(clk) then r <= c; end if;  end process p1;  end rtl;