-- ------------------------------------------
-- description du status du DLX-m en VHDL -
-- version m0.3
-- 4 decembre 1992
-- ------------------------------------------
--
-- le chemin de test n'est pas implemente, seuls figurent les connecteurs
-- associes scout, fonc .
-- Dans la simulation fonc doit etre a 1, scout doivent etre
-- mis a zero .
entity dlxm_sts is
port( ck : in bit ; -- horloge externe
gel : in bit ; -- gel externe
st_datain : in bit_vector(31 downto 0) ; -- data du d_p pour modif status
w_sr : in bit ; -- m_ins(16)=st_datain enable
reset : in bit ; -- connecteur externe reset
ovr : in bit ; -- flag calcule dans data_path
ipc : in bit ; -- flag calcule dans dpt
byte : in bit ; -- ................. controle
ico : in bit ; -- ................. controle
data : in bit ; -- flag acces memoire ........
mem : in bit ; -- ..........................
it : in bit_vector(3 downto 0) ; -- connecteur externe
adr01 : in bit_vector(1 downto 0) ; -- bits poids faible adr du d_path
adr31 : in bit ; -- bit ... fort ..........
rqst : out bit ; -- signal int. masquable
excp : out bit ; -- ..... exception non masquable
--rst : out bit ; -- signal requete reset non masqu.
st_datout : out bit_vector(31 downto 0) ; -- registre status mis a jour
fonc : in bit ;
scout : out bit ;
vdd : in bit ;
vss : in bit ) ;
end dlxm_sts ;
architecture FONCTIONAL of dlxm_sts is
-- --------------------------
-- - Definition des signaux -
-- --------------------------
signal d_status : reg_vector(31 downto 0) register ;
signal sh_reset : bit ;
signal sh_iav : bit ;
signal sh_ico : bit ;
signal sh_dav : bit ;
signal sh_ovr : bit ;
signal sh_it : bit_vector(3 downto 0) ;
-- ----------------------------------
-- - ecriture des shifter du status -
-- ----------------------------------
begin
sh_reset <= st_datain(3) when (w_sr='1') else
'1' when (reset='1') else
'0' ;
sh_iav <= st_datain(8) when (w_sr='1') else
'1' when (ipc='1') else -- ((data='1') and (mem='0') and (adr01/=B"00"))
'0' ;
--(data='1') and (mem='0') and (adr31='1') and (d_status(0)='1'))
sh_ico <= st_datain(9) when (w_sr='1') else
'1' when ( ico ='1') else
'0';
sh_dav <= st_datain(10) when (w_sr='1') else
'1' when (( adr01/= B"00") and (byte='0') and (data='0') and (mem='0')) else
'1' when (( adr31='1') and (data='0') and (mem='0') and (d_status(0)='1')) else
'0' ;
sh_ovr <= st_datain(11) when (w_sr='1') else
'1' when ( ovr='1' ) else
'0' ;
sh_it <= st_datain(15 downto 12) when (w_sr='1') else
it(3 downto 0) ;
-- ------------------------------------
-- - ecriture dans les bascules du sr -
-- ------------------------------------
-- reset et exceptions sont dans "pieges a 1" --------------------------
-- ainsi que les interruptions
------------------------------------------------------------------------
binactif_sr : block (((not ck) and (not gel))='1' and not ck'STABLE)
begin
with w_sr select
d_status(2 downto 0) <= guarded st_datain(2 downto 0) when '1',
d_status(2 downto 0) when others ;
with w_sr select
d_status(7 downto 4) <= guarded st_datain(7 downto 4) when '1',
d_status(7 downto 4) when others ;
with w_sr select
d_status(31 downto 16) <= guarded st_datain(31 downto 16) when '1',
d_status(31 downto 16) when others;
with (w_sr & reset) select
d_status(3) <= guarded d_status(3) when B"00",
sh_reset when others;
with (w_sr & sh_iav) select
d_status(8) <= guarded d_status(8) when B"00",
sh_iav when others;
with (w_sr & sh_ico) select
d_status(9) <= guarded d_status(9) when B"00",
sh_ico when others;
with (w_sr & sh_dav) select
d_status(10) <= guarded d_status(10) when B"00",
sh_dav when others;
with (w_sr & sh_ovr) select
d_status(11) <= guarded d_status(11) when B"00",
sh_ovr when others;
with (w_sr & sh_it(3)) select
d_status(15) <= guarded d_status(15) when B"00",
sh_it(3) when others ;
with (w_sr & sh_it(2)) select
d_status(14) <= guarded d_status(14) when B"00",
sh_it(2) when others ;
with (w_sr & sh_it(1)) select
d_status(13) <= guarded d_status(13) when B"00",
sh_it(1) when others ;
with (w_sr & sh_it(0)) select
d_status(12) <= guarded d_status(12) when B"00",
sh_it(0) when others ;
end block;
-- --------------------------
-- - definition des sorties -
-- --------------------------
--
-- le chemin de test n est pas implemente ------
--
scout <= '0' ;
--
st_datout (31 downto 0) <= d_status(31 downto 0) ;
rqst <= '1' when ((d_status(15 downto 12)/=B"0000") and (d_status(1)='1')) else
'0' ;
excp <= '1' when (d_status(11 downto 10)/=B"00") or (d_status(8)/='0')
else
'0' ;
--rst <= d_status(3) ;
end FONCTIONAL;
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