mmu_dcache.vhd

ARM7的源代码

          and (dcramov.dtramoutsn(i).tag = rs.addr(TAG_HIGH downto TAG_LOW))
        then
          if DSNOOP_FAST then
-- pragma translate_off
            if not is_x(rs.addr(OFFSET_HIGH downto OFFSET_LOW)) then
-- pragma translate_on
            vh.hit(conv_integer(rs.addr(OFFSET_HIGH downto OFFSET_LOW)))(i) := '1';
--             vh.set := std_logic_vector(conv_unsigned(i, SETBITS));
-- pragma translate_off
            end if;
-- pragma translate_on
          else
            snoopaddr := rs.addr(OFFSET_HIGH downto OFFSET_LOW);
            snoopwe := '1'; snoopset := i;        
          end if;
        end if;
      -- bypass tag data on read/write contention
        if (not DSNOOP_FAST) and (rs.writebp(i) = '1') then 
          dcramov.dtramout(i).tag   := rs.addr(TAG_HIGH downto TAG_LOW);
          dcramov.dtramout(i).valid := (others => '0');
        end if;
      end loop;
    end if;

-- generate access parameters during pipeline stall

    if ((r.holdn) = '0') or (DEBUG_UNIT and (dci.dsuen = '1')) then
      taddr := r.xaddress(OFFSET_HIGH downto LINE_LOW);
      --if r.dsuwren = '0' then v.dsuwren := '1'; end if;
    elsif ((dci.enaddr and not dci.read) = '1') or (eholdn = '0')
    then
      taddr := dci.maddress(OFFSET_HIGH downto LINE_LOW);
    else
      taddr := dci.eaddress(OFFSET_HIGH downto LINE_LOW);
    end if;

    if (dci.write or not r.holdn) = '1' then
      maddress := r.xaddress(31 downto 0); signed := r.signed; 
      read := r.read; size := r.size; edata := dci.maddress;
      mmudci_su := r.su; mmudci_read := r.read;
    else
      maddress := dci.maddress(31 downto 0); signed := dci.signed; 
      read := dci.read; size := dci.size; edata := dci.edata;
      mmudci_su := dci.msu; mmudci_read := dci.read;
    end if;

    newtag := dci.maddress(TAG_HIGH downto TAG_LOW);
    vl.waddr := maddress(OFFSET_HIGH downto OFFSET_LOW);  -- lru write address

-- generate cache hit and valid bits

    forcemiss := not dci.asi(3); hit := '0'; set := 0; 
    snoophit := (others => '0'); snoopval := '1';
    for i in DSETS-1 downto 0 loop
      if DSNOOP and DSNOOP_FAST then
-- pragma translate_off
        if not is_x(rh.taddr) then
-- pragma translate_on        
          snoophit(i) := rh.hit(conv_integer(rh.taddr))(i);
-- pragma translate_off
        end if;
-- pragma translate_on
      end if;
      if (dcramov.dtramout(i).tag = dci.maddress(TAG_HIGH downto TAG_LOW)) and (tparerr(i) = '0') and
        (((dcramov.dtramout(i).ctx = r.mmctrl1.ctx) or (r.mmctrl1.e = '0')) or (not M_EN))  
      then hitv(i) := '1'; end if; -- not r.flush; set := i; end if;
      validrawv(i) := hitv(i) and (not r.flush) and (not snoophit(i)) and
	genmux(dci.maddress(LINE_HIGH downto LINE_LOW), dcramov.dtramout(i).valid);
      validv(i) :=  validrawv(i) and not dparerr(i);
      if (hitv(i) and not snoophit(i)) = '1' then ivalid := ivalid or dcramov.dtramout(i).valid; end if;
      snoopval := snoopval and not snoophit(i);
    end loop;
              
    hit := orv(hitv) and not r.flush;

    -- cache hit disabled if mmu-enabled but off or BYPASS
    if (M_EN) and (dci.asi(4 downto 0) = ASI_MMU_BP) then  -- or (r.mmctrl1.e = '0')
      hit := '0';
    end if;
    
    validraw := orv(validrawv);
    valid := orv(validv);
    if DSETS > 1 then 
      for i in DSETS-1 downto 0 loop 
        if hitv(i) = '1' then
	  vset := vset or std_logic_vector(conv_unsigned(i, SETBITS));
        end if;
      end loop;
      set := conv_integer(vset);
    else set := 0; end if;

    if (dci.dsuen and (not r.holdn)) = '1' then diagset := r.xaddress(TAG_LOW+SETBITS-1 downto TAG_LOW);
    else diagset := maddress(TAG_LOW + SETBITS - 1 downto TAG_LOW); end if;
-- pragma translate_off
    if not is_x(diagset) then
-- pragma translate_on
      case DSETS is
      when 1 => ddset := 0;
      when 3 => if conv_integer(diagset) < 3 then ddset := conv_integer(diagset); end if;
      when others => ddset := conv_integer(diagset); 
      end case;
-- pragma translate_off
    end if;
--pragma translate_on

    
    if ((r.holdn and dci.enaddr) = '1')  and (r.dstate = idle) then
        v.hit := hit; v.xaddress := dci.maddress;
	v.read := dci.read; v.size := dci.size;
	v.asi := dci.asi(4 downto 0);  
	v.signed := dci.signed; v.su := dci.msu;
    end if;

-- Store buffer

--    wdata := r.wb.data1;
    if mcdo.ready = '1' then
      v.wb.addr(2) := r.wb.addr(2) or (r.wb.size(0) and r.wb.size(1));
      if r.stpend = '1' then
        v.stpend := r.req; v.wb.data1 := r.wb.data2; 
	v.wb.lock := r.wb.lock and r.req;
      end if;
    end if;
    if mcdo.grant = '1' then v.req := r.burst; v.burst := '0'; end if;

-- main Dcache state machine

    case r.dstate is
    when idle =>			-- Idle state
      if (snoopval = '1') then v.valid := dcramov.dtramout(set).valid;
      else v.valid := (others => '0'); end if;
      v.nomds := r.nomds and not eholdn; v.valid := dcramov.dtramout(set).valid;
      if (r.stpend  = '0') or ((mcdo.ready and not r.req)= '1') then -- wait for store queue
	v.wb.addr := dci.maddress; v.wb.size := dci.size; 
	v.wb.read := dci.read; v.wb.data1 := dci.edata; v.wb.lock := dci.lock;
	v.wb.asi := dci.asi(3 downto 0); 
      end if;
      if (eholdn and (not r.nomds)) = '1' then -- avoid false path through nullify
	if dci.asi(4 downto 0) = ASI_DTAG then rdatasel := dtag; end if;
	if dci.asi(4 downto 0) = ASI_DDATA then rdatasel := dddata; end if;
	if dci.asi(4 downto 0) = ASI_DCTX then rdatasel := dctx; end if;
      end if;
      if (dci.enaddr and eholdn and (not r.nomds) and not dci.nullify) = '1' then
	case dci.asi(4 downto 0) is
	when ASI_ITAG | ASI_IDATA | ASI_ICTX =>		-- Read/write Icache tags
          -- CTX write has to be done through ctxnr & ASI_ITAG
	  if (ico.flush = '1') or (dci.asi(4) = '1') then mexc := '1';
 	 else v.dstate := asi_idtag; v.holdn := '0'; end if;
 	when ASI_IFLUSH =>		-- flush instruction cache
	  if dci.read = '0' then iflush := '1'; end if;
 	when ASI_DFLUSH =>		-- flush data cache
	  if dci.read = '0' then flush := '1'; end if;
 	when ASI_DDATA =>		-- Read/write Dcache data
 	  if (dci.size /= "10") or (r.flush = '1') then -- only word access is allowed
 	    mexc := '1';
 	  elsif (dci.read = '0') then
 	    dwrite := '1'; ddiagwrite := '1';
 	  end if;
 	when ASI_DTAG =>		-- Read/write Dcache tags
 	  if (dci.size /= "10") or (r.flush = '1') then -- allow only word access
 	    mexc := '1';
 	  elsif (dci.read = '0') then
 	    twrite := '1'; tdiagwrite := '1';
 	  end if;
        when ASI_DCTX =>
          -- write has to be done through ctxnr & ASI_DTAG
          if (dci.size /= "10") or (r.flush = '1') or (dci.read = '0') then -- allow only word access
 	    mexc := '1';
 	  end if;
        when ASI_FLUSH_PAGE => -- i/dcache flush page
          if M_EN then
            if dci.read = '0' then
              flush := '1'; iflush := '1'; pflush := '1'; pflushtyp := PFLUSH_PAGE;
            end if;
 	  end if;
        when ASI_FLUSH_CTX => -- i/dcache flush ctx
          if M_EN then
            if dci.read = '0' then
              flush := '1'; iflush := '1'; pflush := '1'; pflushtyp := PFLUSH_CTX;
            end if;
          end if;
        when ASI_MMUFLUSHPROBE =>
          if M_EN then
            if dci.read = '0' then      -- flush
              mmudci_flush_op := '1';
              v.flush_op := not mmudco.grant;
              v.dstate := wflush;
              v.vaddr := dci.maddress; v.holdn := '0'; flush := '1'; iflush := '1';
            end if;
          end if;
        when ASI_MMU_DIAG =>
          -- ASI_MMU_DIAG is not needed,
          if M_EN and M_EN_DIAG then
            if dci.read = '0' then      -- diag access
              mmudci_diag_op := '1';
              v.diag_op := not mmudco.grant;
              v.vaddr := dci.maddress;
            end if;
          end if;  
        when ASI_MMU_DSU =>
        when ASI_MMUREGS =>
          if M_EN then
            rdatasel := misc; mmuregw := not dci.read;
            -- clean fault valid bit
            if dci.read = '1' then
              case dci.maddress(CNR_U downto CNR_D) is
                when CNR_F =>
                  mmudci_fsread := '1';
                when others => null;
              end case;
            end if;
          end if;
	when others =>
--          setrepl := std_logic_vector(conv_unsigned(set, SETBITS));
	  if dci.read = '1' then	-- read access
	    if (not ((mcdo.dcs(0) = '1') 
	       and ((hit and valid and not forcemiss) = '1')))

	    then	-- read miss
	      v.holdn := '0'; v.dstate := wread; v.ready := '0'; v.cache := '1';
              if (not M_EN) or
                ((dci.asi(4 downto 0) = ASI_MMU_BP) or (r.mmctrl1.e = '0'))
              then
                -- cache disabled if mmu-enabled but off or BYPASS
                if (M_EN) then v.cache := '0'; end if;
                
                if ((r.stpend  = '0') or ((mcdo.ready and not r.req) = '1'))
                then	-- wait for store queue
                  
                  v.req := '1';
                  v.burst := dci.size(1) and dci.size(0) and not dci.maddress(2);
                end if;
              else
                -- ## mmu case >
                if (r.stpend  = '0') or ((mcdo.ready and not r.req)= '1')
                then
                  v.wbinit := '1';     -- wb init in idle
                  v.burst := dci.size(1) and dci.size(0) and not dci.maddress(2);
                else
                  v.wbinit := '0';
                end if;
                
                mmudci_trans_op := '1';  -- start translation
                v.trans_op := not mmudco.grant;
                v.vaddr := dci.maddress; 
                v.dstate := rtrans;
                -- ## < mmu case 
              end if;
              
            else       -- read hit
              if (DSETS > 1) and (DCREPLACE = lru) then vl.write := '1'; end if;
            end if;
            
	  else			-- write access
            v.ready := '0';
            if (not M_EN) or
              ((dci.asi(4 downto 0) = ASI_MMU_BP) or (r.mmctrl1.e = '0')) then
                            
              if (r.stpend  = '0') or ((mcdo.ready and not r.req)= '1') then

                v.req := '1'; v.stpend := '1'; 
                v.burst := dci.size(1) and dci.size(0);

                if (dci.size = "11") then v.dstate := dblwrite; end if; -- double store	      
              else		-- wait for store queue
                v.dstate := wwrite; v.holdn := '0';
              end if;
            else
              -- ## mmu case >
              if (r.stpend  = '0') or ((mcdo.ready and not r.req)= '1')
              then
                v.wbinit := '1';     -- wb init in idle
                v.burst := dci.size(1) and dci.size(0);              
              else
                v.wbinit := '0';
              end if;  
              mmudci_trans_op := '1';  -- start translation
              v.trans_op := not mmudco.grant; 
              v.vaddr := dci.maddress; v.holdn := '0';
              v.dstate := wtrans;
              v.dblwdata := dci.size(0) or dci.size(1);  -- "11"
              -- ## < mmu case 
            end if;

            -- note: cache hit disabled if BYPASS
            if (mcdo.dcs(0) = '1') and ((hit and (dci.size(1) or validraw)) = '1') 
            then  -- write hit
              
              twrite := '1'; dwrite := '1';
              if (DSETS > 1) and (DCREPLACE = lru) then vl.write := '1'; end if;
              setrepl := std_logic_vector(conv_unsigned(set, SETBITS));
            end if;

	    if (dci.size = "11") then v.xaddress(2) := '1'; end if;
	  end if;

          if (DSETS > 1) then
    	    vl.set := std_logic_vector(conv_unsigned(set, SETBITS));
            v.setrepl := std_logic_vector(conv_unsigned(set, SETBITS));
            if ((not hit) and (not dparerr(set)) and (not r.flush)) = '1' then
              case DCREPLACE is
              when rnd =>
                if DCLOCK_BIT = 1 then 
                  if lock(conv_integer(r.rndcnt)) = '0' then v.setrepl := r.rndcnt;
                  else
                    v.setrepl := std_logic_vector(conv_unsigned(DSETS-1, SETBITS));
                    for i in DSETS-1 downto 0 loop
                      if (lock(i) = '0') and (i>conv_integer(r.rndcnt)) then
                        v.setrepl := std_logic_vector(conv_unsigned(i, SETBITS));
                      end if;
                    end loop;
                  end if;
                else
                  v.setrepl := r.rndcnt;
                end if;
              when lru =>
-- pragma translate_off
      		if not is_x(dci.maddress(OFFSET_HIGH downto OFFSET_LOW)) then
-- pragma translate_on        
                  v.setrepl := lru_set(rl.lru(conv_integer(dci.maddress(OFFSET_HIGH downto OFFSET_LOW))), lock(0 to DSETS-1));
-- pragma translate_off
      		end if;
-- pragma translate_on        
              when lrr =>
                v.setrepl := (others => '0');
                if DCLOCK_BIT = 1 then 
                  if lock(0) = '1' then v.setrepl(0) := '1';
                  else
                    v.setrepl(0) := dcramov.dtramout(0).lrr xor dcramov.dtramout(1).lrr;
                  end if;
                else
                  v.setrepl(0) := dcramov.dtramout(0).lrr xor dcramov.dtramout(1).lrr;
                end if;
                if v.setrepl(0) = '0' then
                  v.lrr := not dcramov.dtramout(0).lrr;
                else
                  v.lrr := dcramov.dtramout(0).lrr;
                end if;
              end case;
            end if;

            if (DCLOCK_BIT = 1) then
              if (hit and (not dparerr(set)) and lock(set)) = '1' then v.lock := '1';
              else v.lock := '0'; end if;
            end if;
              
          end if;

        end case;
      end if;
    when rtrans =>
      if M_EN then
        if r.stpend = '1' then
          if ((mcdo.ready and not r.req) = '1') then	
            v.ready := '1';       -- buffer store finish
          end if;
        end if;
        
        v.holdn := '0';
        if mmudco.transdata.finish = '1' then
          -- translation error, i.e. page fault
          if (mmudco.transdata.accexc) = '1' then
            v.holdn := '1'; v.dstate := idle;
            mds := '0'; mexc := not r.mmctrl1.nf;
          else
            v.dstate := wread;