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simplify logic of handling flip-flops and latches

This commit is contained in:
Miodrag Milanovic 2022-02-18 09:17:36 +01:00
parent 61752b255f
commit 13a5c28459
1 changed files with 46 additions and 122 deletions
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168
passes/sat/sim.cc
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@ -479,136 +479,60 @@ struct SimInstance
ff_state_t &ff = it.second;
FfData &ff_data = ff.data;
Const current_q = get_state(ff.data.sig_q);
if (ff_data.has_clk) {
// flip-flops
State current_clk = get_state(ff_data.sig_clk)[0];
// handle set/reset
if (ff.data.has_sr) {
Const current_q = get_state(ff.data.sig_q);
Const current_clr = get_state(ff.data.sig_clr);
Const current_set = get_state(ff.data.sig_set);
for(int i=0;i<ff.past_d.size();i++) {
if (current_clr[i] == (ff_data.pol_clr ? State::S1 : State::S0)) {
current_q[i] = State::S0;
}
else if (current_set[i] == (ff_data.pol_set ? State::S1 : State::S0)) {
current_q[i] = State::S1;
} else {
// all below is in sync with clk
if (ff_data.pol_clk ? (ff.past_clk == State::S1 || current_clk != State::S1) :
(ff.past_clk == State::S0 || current_clk != State::S0))
continue;
if (ff_data.has_ce) {
if (ff.past_ce == (ff_data.pol_ce ? State::S1 : State::S0))
current_q[i] = ff.past_d[i];
} else {
current_q[i] = ff.past_d[i];
}
}
}
if (set_state(ff_data.sig_q, current_q))
did_something = true;
} else {
// async reset
if (ff_data.has_arst) {
State current_arst = get_state(ff_data.sig_arst)[0];
if (current_arst == (ff_data.pol_arst ? State::S1 : State::S0)) {
if (set_state(ff_data.sig_q, ff_data.val_arst))
did_something = true;
continue;
}
}
// async load
if (ff_data.has_aload) {
State current_aload = get_state(ff_data.sig_aload)[0];
if (current_aload == (ff_data.pol_aload ? State::S1 : State::S0)) {
if (set_state(ff_data.sig_q, ff.past_ad))
did_something = true;
continue;
}
}
// all below is in sync with clk
if (ff_data.pol_clk ? (ff.past_clk == State::S1 || current_clk != State::S1) :
(ff.past_clk == State::S0 || current_clk != State::S0))
continue;
if (ff_data.pol_clk ? (ff.past_clk == State::S0 && current_clk != State::S0) :
(ff.past_clk == State::S1 && current_clk != State::S1)) {
bool ce = ff.past_ce == (ff_data.pol_ce ? State::S1 : State::S0);
// chip enable priority over reset
if (ff_data.ce_over_srst && ff_data.has_ce) {
if (ff.past_ce != (ff_data.pol_ce ? State::S1 : State::S0))
continue;
if (ff_data.ce_over_srst && ff_data.has_ce && !ce) continue;
// set if no ce, or ce is enabled
if (!ff_data.has_ce || (ff_data.has_ce && ce)) {
current_q = ff.past_d;
}
// handle sync reset
if (ff_data.has_srst) {
if (ff.past_srst == (ff_data.pol_srst ? State::S1 : State::S0)) {
if (set_state(ff_data.sig_q, ff_data.val_srst))
did_something = true;
continue;
}
// override if sync reset
if ((ff_data.has_srst) && (ff.past_srst == (ff_data.pol_srst ? State::S1 : State::S0))) {
current_q = ff_data.val_srst;
}
// reset had priority over chip enable
if (!ff_data.ce_over_srst && ff_data.has_ce) {
if (ff.past_ce != (ff_data.pol_ce ? State::S1 : State::S0))
continue;
}
if (set_state(ff_data.sig_q, ff.past_d))
did_something = true;
}
} else {
// handle set/reset
if (ff.data.has_sr) {
Const current_q = get_state(ff.data.sig_q);
Const current_clr = get_state(ff.data.sig_clr);
Const current_set = get_state(ff.data.sig_set);
for(int i=0;i<current_q.size();i++) {
if (current_clr[i] == (ff_data.pol_clr ? State::S1 : State::S0)) {
current_q[i] = State::S0;
}
else if (current_set[i] == (ff_data.pol_set ? State::S1 : State::S0)) {
current_q[i] = State::S1;
} else {
if (ff_data.has_aload) {
Const current_ad = get_state(ff.data.sig_ad);
State current_aload = get_state(ff_data.sig_aload)[0];
if (current_aload == (ff_data.pol_aload ? State::S1 : State::S0)) {
current_q[i] = current_ad[i];
}
}
}
}
if (set_state(ff_data.sig_q, current_q))
did_something = true;
}
// async load is true for all latches
else if (ff_data.has_aload) {
// async reset
if (ff_data.has_arst) {
State current_arst = get_state(ff_data.sig_arst)[0];
if (current_arst == (ff_data.pol_arst ? State::S1 : State::S0)) {
if (set_state(ff_data.sig_q, ff_data.val_arst))
did_something = true;
continue;
}
}
State current_aload = get_state(ff_data.sig_aload)[0];
if (current_aload == (ff_data.pol_aload ? State::S1 : State::S0)) {
if (set_state(ff_data.sig_q, get_state(ff.data.sig_ad)))
did_something = true;
}
} else if (ff_data.has_gclk) {
// $ff
if (set_state(ff_data.sig_q, ff.past_d))
did_something = true;
}
}
// async load
if (ff_data.has_aload) {
State current_aload = get_state(ff_data.sig_aload)[0];
if (current_aload == (ff_data.pol_aload ? State::S1 : State::S0)) {
current_q = ff_data.has_clk ? ff.past_ad : get_state(ff.data.sig_ad);
}
}
// async reset
if (ff_data.has_arst) {
State current_arst = get_state(ff_data.sig_arst)[0];
if (current_arst == (ff_data.pol_arst ? State::S1 : State::S0)) {
current_q = ff_data.val_arst;
}
}
// handle set/reset
if (ff.data.has_sr) {
Const current_clr = get_state(ff.data.sig_clr);
Const current_set = get_state(ff.data.sig_set);
for(int i=0;i<ff.past_d.size();i++) {
if (current_clr[i] == (ff_data.pol_clr ? State::S1 : State::S0)) {
current_q[i] = State::S0;
}
else if (current_set[i] == (ff_data.pol_set ? State::S1 : State::S0)) {
current_q[i] = State::S1;
}
}
}
if (ff_data.has_gclk) {
// $ff
current_q = ff.past_d;
}
if (set_state(ff_data.sig_q, current_q))
did_something = true;
}
for (auto &it : mem_database)