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wfjm.w11/rtl/ibus/ibd_iist.vhd
wfjm d3cce101a7 SPDX: rtl/*/*.vhd
2019-07-12 19:01:49 +02:00

677 lines
28 KiB
VHDL
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-- $Id: ibd_iist.vhd 1181 2019-07-08 17:00:50Z mueller $
-- SPDX-License-Identifier: GPL-3.0-or-later
-- Copyright 2009-2016 by Walter F.J. Mueller <W.F.J.Mueller@gsi.de>
--
------------------------------------------------------------------------------
-- Module Name: ibd_iist - syn
-- Description: ibus dev(loc): IIST
--
-- Dependencies: -
-- Test bench: -
-- Target Devices: generic
-- Tool versions: ise 8.2-14.7; viv 2014.4-2016.1; ghdl 0.18-0.33
--
-- Synthesized (xst):
-- Date Rev ise Target flop lutl lutm slic t peri
-- 2010-10-17 333 12.1 M53d xc3s1000-4 112 510 0 291 s 15.8
-- 2010-10-17 314 12.1 M53d xc3s1000-4 111 504 0 290 s 15.6
-- 2009-06-01 223 10.1.03 K39 xc3s1000-4 111 439 0 256 s 9.8
-- 2009-06-01 221 10.1.03 K39 xc3s1000-4 111 449 0 258 s 13.3
--
-- Revision History:
-- Date Rev Version Comment
-- 2016-05-22 767 0.8.2 don't init N_REGS (vivado fix for fsm inference)
-- 2011-11-18 427 0.8.1 now numeric_std clean
-- 2010-10-17 333 0.8 use ibus V2 interface
-- 2009-06-07 224 0.7 send inverted stc_stp; remove pgc_err; honor msk_im
-- also for dcf_dcf and exc_rte; add iist_mreq and
-- iist_sreq, boot and lock interfaces
-- 2009-06-05 223 0.6 level interrupt, parity logic, exc.ui logic
-- st logic modified (partially tested)
-- 2009-06-01 221 0.5 Initial version (untested, lock&boot missing)
------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use work.slvtypes.all;
use work.iblib.all;
use work.ibdlib.all;
-- ----------------------------------------------------------------------------
entity ibd_iist is -- ibus dev(loc): IIST
-- fixed address: 177500
generic (
SID : slv2 := "00"); -- self id
port (
CLK : in slbit; -- clock
CE_USEC : in slbit; -- usec pulse
RESET : in slbit; -- system reset
BRESET : in slbit; -- ibus reset
IB_MREQ : in ib_mreq_type; -- ibus request
IB_SRES : out ib_sres_type; -- ibus response
EI_REQ : out slbit; -- interrupt request
EI_ACK : in slbit; -- interrupt acknowledge
IIST_BUS : in iist_bus_type; -- iist bus (input from all iist's)
IIST_OUT : out iist_line_type; -- iist output
IIST_MREQ : out iist_mreq_type; -- iist->cpu requests
IIST_SRES : in iist_sres_type -- cpu->iist responses
);
end ibd_iist;
architecture syn of ibd_iist is
constant ibaddr_iist : slv16 := slv(to_unsigned(8#177500#,16));
constant tdlysnd : natural := 150; -- send delay timer
constant ibaddr_acr : slv1 := "0"; -- acr address offset
constant ibaddr_adr : slv1 := "1"; -- adr address offset
constant acr_ibf_clr : integer := 15; -- clear flag
subtype acr_ibf_sid is integer range 9 downto 8; -- self id
subtype acr_ibf_ac is integer range 3 downto 0; -- ac code
constant ac_pge : slv4 := "0000"; -- 0 program generated enables
constant ac_pgc : slv4 := "0001"; -- 1 program generated control/status
constant ac_ste : slv4 := "0010"; -- 2 sanity timer enables
constant ac_stc : slv4 := "0011"; -- 3 sanity timer control/status
constant ac_msk : slv4 := "0100"; -- 4 input masks
constant ac_pgf : slv4 := "0101"; -- 5 program generated flags
constant ac_stf : slv4 := "0110"; -- 6 sanity timer flags
constant ac_dcf : slv4 := "0111"; -- 7 disconnect flags
constant ac_exc : slv4 := "1000"; -- 10 exceptions
constant ac_mtc : slv4 := "1101"; -- 15 maintenance control
subtype pge_ibf_pbe is integer range 11 downto 8; -- pg boot ena
subtype pge_ibf_pie is integer range 3 downto 0; -- pg int ena
constant pgc_ibf_err : integer := 15; -- error
constant pgc_ibf_grj : integer := 14; -- go reject
constant pgc_ibf_pgrmr : integer := 13; -- pg req refused
constant pgc_ibf_strmr : integer := 12; -- st req refused
constant pgc_ibf_rdy : integer := 11; -- ready flag
subtype pgc_ibf_sid is integer range 9 downto 8; -- self id
constant pgc_ibf_ip : integer := 3; -- int pending
constant pgc_ibf_ie : integer := 2; -- int enable
constant pgc_ibf_ptp : integer := 1; -- pg parity
constant pgc_ibf_go : integer := 0; -- go flag
subtype ste_ibf_sbe is integer range 11 downto 8; -- st boot enable
subtype ste_ibf_sie is integer range 3 downto 0; -- st int enable
subtype stc_ibf_count is integer range 15 downto 8; -- count
constant stc_ibf_tmo : integer := 3; -- timeout
constant stc_ibf_lke : integer := 2; -- lockup enable
constant stc_ibf_stp : integer := 1; -- st parity
constant stc_ibf_enb : integer := 0; -- enable
subtype msk_ibf_bm is integer range 11 downto 8; -- boot mask
subtype msk_ibf_im is integer range 3 downto 0; -- int mask
subtype pgf_ibf_pbf is integer range 11 downto 8; -- boot flags
subtype pgf_ibf_pif is integer range 3 downto 0; -- int flags
subtype stf_ibf_sbf is integer range 11 downto 8; -- boot flags
subtype stf_ibf_sif is integer range 3 downto 0; -- int flags
subtype dcf_ibf_brk is integer range 11 downto 8; -- break flags
subtype dcf_ibf_dcf is integer range 3 downto 0; -- disconnect flags
subtype exc_ibf_ui is integer range 11 downto 8; -- unexpected int
subtype exc_ibf_rte is integer range 3 downto 0; -- transm. error
constant mtc_ibf_mttp : integer := 11; -- maint. type
constant mtc_ibf_mfrm : integer := 10; -- maint. frame err
subtype mtc_ibf_mid is integer range 9 downto 8; -- maint. id
constant mtc_ibf_dsbt : integer := 3; -- disable boot
constant mtc_ibf_enmxd : integer := 2; -- enable maint mux
constant mtc_ibf_enmlp : integer := 1; -- enable maint loop
constant mtc_ibf_dsdrv : integer := 0; -- disable driver
type state_type is (
s_idle, -- idle state
s_clear, -- handle acr clr
s_stsnd, -- handle st transmit
s_pgsnd -- handle pg transmit
);
type regs_type is record -- state registers
ibsel : slbit; -- ibus select
acr_ac : slv4; -- acr: ac
pge_pbe : slv4; -- pge: pg boot ena
pge_pie : slv4; -- pge: pg int ena
pgc_grj : slbit; -- pgc: go reject
pgc_pgrmr : slbit; -- pgc: pg req refused
pgc_strmr : slbit; -- pgc: st req refused
pgc_ie : slbit; -- pgc: int enable
pgc_ptp : slbit; -- pgc: pg parity
ste_sbe : slv4; -- ste: st boot enable
ste_sie : slv4; -- ste: st int enable
stc_count : slv8; -- stc: count
stc_tmo : slbit; -- stc: timeout
stc_lke : slbit; -- stc: lockup enable
stc_stp : slbit; -- stc: st parity
stc_enb : slbit; -- stc: enable
msk_bm : slv4; -- msk: boot mask
msk_im : slv4; -- msk: int mask
pgf_pbf : slv4; -- pgf: boot flags
pgf_pif : slv4; -- pgf: int flags
stf_sbf : slv4; -- stf: boot flags
stf_sif : slv4; -- stf: int flags
dcf_brk : slv4; -- dcf: break flags
dcf_dcf : slv4; -- dcf: disconnect flags
exc_ui : slv4; -- exc: unexpected int
exc_rte : slv4; -- exc: transm. error
mtc_mttp : slbit; -- mtc: maint. type
mtc_mfrm : slbit; -- mtc: maint. frame err
mtc_mid : slv2; -- mtc: maint. id
mtc_dsbt : slbit; -- mtc: disable boot
mtc_enmxd : slbit; -- mtc: enable maint mux
mtc_enmlp : slbit; -- mtc: enable maint loop
mtc_dsdrv : slbit; -- mtc: disable driver
state : state_type; -- state
req_clear : slbit; -- request clear
req_stsnd : slbit; -- request sanity timer transmit
req_pgsnd : slbit; -- request prog. gen. transmit
tcnt256 : slv8; -- usec clock divider for st clock
tcntsnd : slv8; -- timer for transmit delay
req_lock : slbit; -- cpu lock request
req_boot : slbit; -- cpu boot request
end record regs_type;
constant regs_init : regs_type := (
'0', -- ibsel
"0000", -- acr_ac
"0000","0000", -- pge_pbe, pge_pie
'0', -- pgc_grj
'0','0', -- pgc_pgrmr, pgc_strmr
'0','0', -- pgc_ie, pgc_ptp
"0000","0000", -- ste_sbe, ste_sie
(others=>'0'), -- stc_count
'0','0', -- stc_tmo, stc_lke
'0','0', -- stc_stp, stc_enb
"0000","0000", -- msk_bm, msk_im
"0000","0000", -- pgf_pbf, pgf_pif
"0000","0000", -- stf_sbf, stf_sif
"0000","0000", -- dcf_brk, dcf_dcf
"0000","0000", -- exc_ui, exc_rte
'0','0', -- mtc_mttp, mtc_mfrm
"00", -- mtc_mid
'0','0', -- mtc_dsbt, mtc_enmxd
'0','0', -- mtc_enmlp, mtc_dsdrv
s_idle, -- state
'0', -- req_clear
'0','0', -- req_stsnd, req_pgsnd
(others=>'0'), -- tcnt256
(others=>'0'), -- tcntsnd
'0','0' -- req_lock, req_boot
);
signal R_REGS : regs_type := regs_init;
signal N_REGS : regs_type; -- don't init (vivado fix for fsm infer)
begin
proc_regs: process (CLK)
begin
if rising_edge(CLK) then
if BRESET = '1' or -- BRESET is 1 for system and ibus reset
R_REGS.req_clear='1' then
R_REGS <= regs_init; --
if RESET = '0' then -- if RESET=0 we do just an ibus reset
R_REGS.pgf_pbf <= N_REGS.pgf_pbf; -- don't reset pg boot flags
R_REGS.stf_sbf <= N_REGS.stf_sbf; -- don't reset st boot flags
R_REGS.tcnt256 <= N_REGS.tcnt256; -- don't reset st clock divider
end if;
else
R_REGS <= N_REGS;
end if;
end if;
end process proc_regs;
proc_next : process (R_REGS, CE_USEC, IB_MREQ,
IIST_BUS(0), IIST_BUS(1), IIST_BUS(2), IIST_BUS(3),
IIST_SRES)
variable r : regs_type := regs_init;
variable n : regs_type := regs_init;
variable ibhold : slbit := '0';
variable idout : slv16 := (others=>'0');
variable ibreq : slbit := '0';
variable ibrd : slbit := '0';
variable ibw0 : slbit := '0';
variable ibw1 : slbit := '0';
variable int_or : slbit := '0';
variable tcnt256_end : slbit := '0';
variable tcntsnd_end : slbit := '0';
variable eff_id : slv2 := "00";
variable eff_bus : iist_bus_type := iist_bus_init;
variable par_err : slbit := '0';
variable act_ibit : slbit := '0';
variable act_bbit : slbit := '0';
variable iout : iist_line_type := iist_line_init;
begin
r := R_REGS;
n := R_REGS;
ibhold := '0';
idout := (others=>'0');
ibreq := IB_MREQ.re or IB_MREQ.we;
ibrd := IB_MREQ.re;
ibw0 := IB_MREQ.we and IB_MREQ.be0;
ibw1 := IB_MREQ.we and IB_MREQ.be1;
int_or := r.pgc_grj or r.pgc_pgrmr or r.pgc_strmr;
for i in r.dcf_dcf'range loop
int_or := int_or or r.dcf_dcf(i) or
r.exc_rte(i) or
r.pgf_pif(i) or
r.stf_sif(i);
end loop; -- i
tcnt256_end := '0';
if CE_USEC='1' and r.stc_enb='1'then -- if st enabled on every usec
n.tcnt256 := slv(unsigned(r.tcnt256) + 1); -- advance 8 bit counter
if unsigned(r.tcnt256) = 255 then -- if wrap
tcnt256_end := '1'; -- signal 256 usec passed
end if;
end if;
tcntsnd_end := '0';
n.tcntsnd := slv(unsigned(r.tcntsnd) + 1); -- advance send timer counter
if unsigned(r.tcntsnd) = tdlysnd-1 then -- if delay time reached
tcntsnd_end := '1'; -- signal end
end if;
eff_id := SID; -- effective self-id, normally SID
if r.mtc_enmxd = '1' then -- if maint. mux enabled
eff_id := r.mtc_mid; -- use maint. id
end if;
eff_bus := IIST_BUS;
par_err := '0';
act_ibit := '0';
act_bbit := '0';
iout := iist_line_init; -- default state of out line
-- ibus address decoder
n.ibsel := '0';
if IB_MREQ.aval='1' and
IB_MREQ.addr(12 downto 2)=ibaddr_iist(12 downto 2) then
n.ibsel := '1';
end if;
-- internal state machine
case r.state is
when s_idle => -- idle state
n.tcntsnd := (others=>'0'); -- keep send delay timer zero
if r.req_stsnd = '1' then -- sanity timer request pending
n.state := s_stsnd;
elsif r.req_pgsnd = '1' then -- prog. gen. request pending
n.state := s_pgsnd;
end if;
when s_clear => -- handle acr clr
ibhold := r.ibsel; -- keep req pending if selected
-- r.req_clear is set when in this state and cause a reset in prog_regs
-- --> n.req_clear := '0';
-- --> n.state := s_idle;
when s_stsnd => -- handle st transmit
if tcntsnd_end = '1' then -- send delay expired
n.req_stsnd := '0'; -- clear st transmit request
iout.req := '1'; -- do transmit
iout.stf := '1'; -- signal type = st
iout.imask := r.ste_sie; -- int enables
iout.bmask := r.ste_sbe; -- boot enables
iout.par := not r.stc_stp; -- send parity (odd incl. stf!)
iout.frm := '0'; -- frame always ok
n.state := s_idle;
end if;
when s_pgsnd => -- handle pg transmit
if tcntsnd_end = '1' then -- send delay expired
n.req_pgsnd := '0'; -- clear pg transmit request
iout.req := '1'; -- do transmit
iout.stf := '0'; -- signal type = pg
iout.imask := r.pge_pie; -- int enables
iout.bmask := r.pge_pbe; -- boot enables
iout.par := r.pgc_ptp; -- send parity
iout.frm := '0'; -- frame always ok
n.state := s_idle;
end if;
when others => null;
end case;
if r.mtc_enmxd = '1' then -- if maintenance mux enabled
iout.stf := r.mtc_mttp; -- force type from mtc_mttp
iout.frm := r.mtc_mfrm; -- force frame from mtc_mfrm
end if;
-- ibus transactions
if r.ibsel = '1' and ibhold='0' then
if IB_MREQ.addr(1 downto 1) = "0" then -- ACR -- access control reg -----
idout(acr_ibf_sid) := SID;
idout(acr_ibf_ac) := r.acr_ac;
if ibw1 = '1' then
if IB_MREQ.din(acr_ibf_clr) = '1' then
n.req_clear := '1';
n.state := s_clear;
end if;
end if;
if ibw0 = '1' then
n.acr_ac := IB_MREQ.din(acr_ibf_ac);
end if;
else -- ADR -- access data reg --------
case r.acr_ac is
when ac_pge => -- PGE -- program gen enables --------
idout(pge_ibf_pbe) := r.pge_pbe;
idout(pge_ibf_pie) := r.pge_pie;
if IB_MREQ.we = '1' then
if r.req_pgsnd = '0' then -- no pg transmit pending
if ibw1 = '1' then
n.pge_pbe := IB_MREQ.din(pge_ibf_pbe);
end if;
if ibw0 = '1' then
n.pge_pie := IB_MREQ.din(pge_ibf_pie);
end if;
else -- if collision with pg transmit
n.pgc_pgrmr := '1'; -- set pge refused flag
end if;
end if;
when ac_pgc => -- PGC -- program gen control/status -
idout(pgc_ibf_err) := r.pgc_grj or r.pgc_pgrmr or r.pgc_strmr;
idout(pgc_ibf_grj) := r.pgc_grj;
idout(pgc_ibf_pgrmr) := r.pgc_pgrmr;
idout(pgc_ibf_strmr) := r.pgc_strmr;
idout(pgc_ibf_rdy) := not r.req_pgsnd;
idout(pgc_ibf_sid) := eff_id;
idout(pgc_ibf_ip) := int_or;
idout(pgc_ibf_ie) := r.pgc_ie;
idout(pgc_ibf_ptp) := r.pgc_ptp;
if ibw1 = '1' then
if IB_MREQ.din(pgc_ibf_err) = '1' then -- '1' written into ERR
n.pgc_grj := '0'; -- clears GRJ
n.pgc_pgrmr := '0'; -- clears PGRMR
n.pgc_strmr := '0'; -- clears STRMR
end if;
end if;
if ibw0 = '1' then
n.pgc_ie := IB_MREQ.din(pgc_ibf_ie);
n.pgc_ptp := IB_MREQ.din(pgc_ibf_ptp);
if IB_MREQ.din(pgc_ibf_go) = '1' then -- GO bit set
if r.req_pgsnd = '0' then -- if ready (no pgsnd pend)
n.req_pgsnd := '1'; -- request pgsnd
else -- if not ready
n.pgc_grj := '1'; -- set go reject flag
end if;
end if;
end if;
when ac_ste => -- STE -- sanity timer enables -------
idout(ste_ibf_sbe) := r.ste_sbe;
idout(ste_ibf_sie) := r.ste_sie;
if IB_MREQ.we = '1' then
if r.req_stsnd = '0' then -- no st transmit pending
if ibw1 = '1' then
n.ste_sbe := IB_MREQ.din(ste_ibf_sbe);
end if;
if ibw0 = '1' then
n.ste_sie := IB_MREQ.din(ste_ibf_sie);
end if;
else -- if collision with st transmit
n.pgc_strmr := '1'; -- set ste refused flag
end if;
end if;
when ac_stc => -- STC -- sanity timer control/status
idout(stc_ibf_count) := r.stc_count;
idout(stc_ibf_tmo) := r.stc_tmo;
idout(stc_ibf_lke) := r.stc_lke;
idout(stc_ibf_stp) := r.stc_stp;
idout(stc_ibf_enb) := r.stc_enb;
if ibw1 = '1' then
n.stc_count := IB_MREQ.din(stc_ibf_count); -- reset st count
n.tcnt256 := (others=>'0'); -- reset usec count
end if;
if ibw0 = '1' then
if IB_MREQ.din(stc_ibf_tmo) = '1' then -- 1 written into TMO
n.stc_tmo := '0';
end if;
n.stc_lke := IB_MREQ.din(stc_ibf_lke);
n.stc_stp := IB_MREQ.din(stc_ibf_stp);
n.stc_enb := IB_MREQ.din(stc_ibf_enb);
end if;
when ac_msk => -- MSK -- input masks ----------------
idout(msk_ibf_bm) := r.msk_bm;
idout(msk_ibf_im) := r.msk_im;
if ibw1 = '1' then
n.msk_bm := IB_MREQ.din(msk_ibf_bm);
end if;
if ibw0 = '1' then
n.msk_im := IB_MREQ.din(msk_ibf_im);
end if;
when ac_pgf => -- PGF -- program generated flags ----
idout(pgf_ibf_pbf) := r.pgf_pbf;
idout(pgf_ibf_pif) := r.pgf_pif;
if ibw1 = '1' then
n.pgf_pbf := r.pgf_pbf and not IB_MREQ.din(pgf_ibf_pbf);
end if;
if ibw0 = '1' then
n.pgf_pif := r.pgf_pif and not IB_MREQ.din(pgf_ibf_pif);
end if;
when ac_stf => -- STF -- sanity timer flags ---------
idout(stf_ibf_sbf) := r.stf_sbf;
idout(stf_ibf_sif) := r.stf_sif;
if ibw1 = '1' then
n.stf_sbf := r.stf_sbf and not IB_MREQ.din(stf_ibf_sbf);
end if;
if ibw0 = '1' then
n.stf_sif := r.stf_sif and not IB_MREQ.din(stf_ibf_sif);
end if;
when ac_dcf => -- DCE -- disconnect flags -----------
idout(dcf_ibf_brk) := r.dcf_brk;
idout(dcf_ibf_dcf) := r.dcf_dcf;
if ibw0 = '1' then
n.dcf_dcf := r.dcf_dcf and not IB_MREQ.din(dcf_ibf_dcf);
end if;
when ac_exc => -- EXC -- exceptions -----------------
idout(exc_ibf_ui) := r.exc_ui;
idout(exc_ibf_rte) := r.exc_rte;
if ibw1 = '1' then
n.exc_ui := r.exc_ui and not IB_MREQ.din(exc_ibf_ui);
end if;
if ibw0 = '1' then
n.exc_rte := r.exc_rte and not IB_MREQ.din(exc_ibf_rte);
end if;
when ac_mtc => -- MTC -- maintenance control --------
idout(mtc_ibf_mttp) := r.mtc_mttp;
idout(mtc_ibf_mfrm) := r.mtc_mfrm;
idout(mtc_ibf_mid) := r.mtc_mid;
idout(mtc_ibf_dsbt) := r.mtc_dsbt;
idout(mtc_ibf_enmxd) := r.mtc_enmxd;
idout(mtc_ibf_enmlp) := r.mtc_enmlp;
idout(mtc_ibf_dsdrv) := r.mtc_dsdrv;
if ibw1 = '1' then
n.mtc_mttp := IB_MREQ.din(mtc_ibf_mttp);
n.mtc_mfrm := IB_MREQ.din(mtc_ibf_mfrm);
n.mtc_mid := IB_MREQ.din(mtc_ibf_mid);
end if;
if ibw0 = '1' then
n.mtc_dsbt := IB_MREQ.din(mtc_ibf_dsbt);
n.mtc_enmxd := IB_MREQ.din(mtc_ibf_enmxd);
n.mtc_enmlp := IB_MREQ.din(mtc_ibf_enmlp);
n.mtc_dsdrv := IB_MREQ.din(mtc_ibf_dsdrv);
end if;
when others => -- access to undefined AC code -------
null;
end case;
if unsigned(r.acr_ac) <= unsigned(ac_exc) then -- if ac 0,..,10
if IB_MREQ.rmw = '0' then -- if not 1st part of rmw
n.acr_ac := slv(unsigned(r.acr_ac) + 1); -- autoincrement
end if;
end if;
end if;
end if;
-- sanity timer
if tcnt256_end = '1' then -- if 256 usec expired (and enabled)
n.stc_count := slv(unsigned(r.stc_count) - 1);
if unsigned(r.stc_count) = 0 then -- if sanity timer expired
n.stc_tmo := '1'; -- set timeout flag
n.req_stsnd := '1'; -- request st transmit
if r.stc_lke = '1' then -- if lockup enabled
n.req_lock := '1'; -- request lockup
end if;
end if;
end if;
-- process iist bus inputs
if r.mtc_enmlp = '1' then -- if mainentance loop
for i in eff_bus'range loop
eff_bus(i) := iout; -- local signal on all input ports
eff_bus(i).dcf := '0'; -- all ports considered connected
end loop; -- i
end if;
for i in eff_bus'range loop
par_err := eff_bus(i).stf xor
eff_bus(i).imask(0) xor eff_bus(i).imask(1) xor
eff_bus(i).imask(2) xor eff_bus(i).imask(3) xor
eff_bus(i).bmask(0) xor eff_bus(i).bmask(1) xor
eff_bus(i).bmask(2) xor eff_bus(i).bmask(3) xor
not eff_bus(i).par;
act_ibit := eff_bus(i).imask(to_integer(unsigned(eff_id)));
act_bbit := eff_bus(i).bmask(to_integer(unsigned(eff_id)));
n.dcf_brk(i) := eff_bus(i).dcf; -- trace dcf state in brk
if eff_bus(i).dcf = '1' then -- if disconnected
if r.msk_im(i) = '0' then -- if not disabled
n.dcf_dcf(i) := '1'; -- set dcf flag
end if;
else -- if connected
if eff_bus(i).req = '1' then -- request received ?
if eff_bus(i).frm='1' or -- frame error seen ?
par_err='1' then -- parity error seen ?
if r.msk_im(i) = '0' then -- if not disabled
n.exc_rte(i) := '1'; -- set rte flag
end if;
else -- here if valid request seen
if act_ibit = '1' then -- interrupt request
if r.msk_im(i) = '1' then -- if disabled
n.exc_ui(i) := '1'; -- set ui flag
else -- if enabled
n.req_lock := '0'; -- release lock
if eff_bus(i).stf = '0' then -- and pg request
n.pgf_pif(i) := '1'; -- set pif flag
else -- and st request
n.stf_sif(i) := '1'; -- set sif flag
end if;
end if;
end if; -- act_ibit='1'
if act_bbit = '1' then -- boot request
if r.msk_bm(i) = '1' then -- if msk disabled
n.exc_ui(i) := '1'; -- set ui flag
else -- if msk enabled
if r.mtc_dsbt = '0' then -- if mtc enabled
n.req_lock := '0'; -- release lock
n.req_boot := '1'; -- request boot
end if;
if eff_bus(i).stf = '0' then -- and pg request
n.pgf_pbf(i) := '1'; -- set pbf flag
else -- and st request
n.stf_sbf(i) := '1'; -- set sbf flag
end if;
end if;
end if; -- act_bbit='1'
end if;
end if;
end if;
end loop;
-- process cpu->iist responses
if IIST_SRES.ack_lock = '1' then
n.req_lock := '0';
end if;
if IIST_SRES.ack_boot = '1' then
n.req_boot := '0';
end if;
N_REGS <= n;
IB_SRES.dout <= idout;
IB_SRES.ack <= r.ibsel and ibreq;
IB_SRES.busy <= ibhold and ibreq;
EI_REQ <= r.pgc_ie and int_or;
if r.mtc_dsdrv = '1' then -- if driver disconnected
iout.dcf := '1'; -- set dcf flag
iout.req := '0'; -- suppress requests
end if;
IIST_OUT <= iout; -- and finally send it out...
IIST_MREQ.lock <= r.req_lock;
IIST_MREQ.boot <= r.req_boot;
end process proc_next;
end syn;
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