luke
/
iverilog
mirror of https://github.com/steveicarus/iverilog.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Do not schedule a new event if the previous event has the same value. 

If the previous event has exactly the same value as this event then
we do not add this event to the event queue.
This commit is contained in:
Cary R 2009-08-06 20:32:10 -07:00 committed by Stephen Williams
parent e44247f82c
commit 2e820ca6f0
2 changed files with 57 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
vvp/delay.cc
View File

@ -140,6 +140,7 @@ vvp_fun_delay::vvp_fun_delay(vvp_net_t*n, vvp_bit4_t init, const vvp_delay_t&d)
cur_vec8_ = vvp_vector8_t(cur_vec4_, 6, 6);
cur_real_ = 0.0;
list_ = 0;
type_ = UNKNOWN_DELAY;
initial_ = true;
// Calculate the values used when converting variable delays
// to simulation time units.
@ -160,10 +161,48 @@ vvp_fun_delay::~vvp_fun_delay()
delete cur;
}
bool vvp_fun_delay::clean_pulse_events_(vvp_time64_t use_delay,
const vvp_vector4_t&bit)
{
if (list_ == 0) return false;
/* If the most recent event and the new event have the same
* value then we need to skip the new event. */
if (list_->next->ptr_vec4.eeq(bit)) return true;
clean_pulse_events_(use_delay);
return false;
}
bool vvp_fun_delay::clean_pulse_events_(vvp_time64_t use_delay,
const vvp_vector8_t&bit)
{
if (list_ == 0) return false;
/* If the most recent event and the new event have the same
* value then we need to skip the new event. */
if (list_->next->ptr_vec8.eeq(bit)) return true;
clean_pulse_events_(use_delay);
return false;
}
bool vvp_fun_delay::clean_pulse_events_(vvp_time64_t use_delay,
double bit)
{
if (list_ == 0) return false;
/* If the most recent event and the new event have the same
* value then we need to skip the new event. */
if (list_->next->ptr_real == bit) return true;
clean_pulse_events_(use_delay);
return false;
}
void vvp_fun_delay::clean_pulse_events_(vvp_time64_t use_delay)
{
if (list_ == 0)
return;
assert(list_ != 0);
do {
struct event_*cur = list_->next;
@ -219,6 +258,7 @@ void vvp_fun_delay::recv_vec4(vvp_net_ptr_t port, const vvp_vector4_t&bit,
/* This is an initial value so it needs to be compared to all the
bits (the order the bits are changed is not deterministic). */
if (initial_) {
type_ = VEC4_DELAY;
vvp_bit4_t cur_val = cur_vec4_.value(0);
use_delay = delay_.get_delay(cur_val, bit.value(0));
for (unsigned idx = 1 ; idx < bit.size() ; idx += 1) {
@ -227,6 +267,7 @@ void vvp_fun_delay::recv_vec4(vvp_net_ptr_t port, const vvp_vector4_t&bit,
if (tmp > use_delay) use_delay = tmp;
}
} else {
assert(type_ == VEC4_DELAY);
/* How many bits to compare? */
unsigned use_wid = cur_vec4_.size();
@ -246,7 +287,7 @@ void vvp_fun_delay::recv_vec4(vvp_net_ptr_t port, const vvp_vector4_t&bit,
/* what *should* happen here is we check to see if there is a
transaction in the queue. This would be a pulse that needs to be
eliminated. */
clean_pulse_events_(use_delay);
if (clean_pulse_events_(use_delay, bit)) return;
vvp_time64_t use_simtime = schedule_simtime() + use_delay;
@ -273,6 +314,7 @@ void vvp_fun_delay::recv_vec8(vvp_net_ptr_t port, const vvp_vector8_t&bit)
/* This is an initial value so it needs to be compared to all the
bits (the order the bits are changed is not deterministic). */
if (initial_) {
type_ = VEC8_DELAY;
vvp_bit4_t cur_val = cur_vec8_.value(0).value();
use_delay = delay_.get_delay(cur_val, bit.value(0).value());
for (unsigned idx = 1 ; idx < bit.size() ; idx += 1) {
@ -281,6 +323,7 @@ void vvp_fun_delay::recv_vec8(vvp_net_ptr_t port, const vvp_vector8_t&bit)
if (tmp > use_delay) use_delay = tmp;
}
} else {
assert(type_ == VEC8_DELAY);
/* How many bits to compare? */
unsigned use_wid = cur_vec8_.size();
@ -302,7 +345,7 @@ void vvp_fun_delay::recv_vec8(vvp_net_ptr_t port, const vvp_vector8_t&bit)
/* what *should* happen here is we check to see if there is a
transaction in the queue. This would be a pulse that needs to be
eliminated. */
clean_pulse_events_(use_delay);
if (clean_pulse_events_(use_delay, bit)) return;
vvp_time64_t use_simtime = schedule_simtime() + use_delay;
@ -351,11 +394,14 @@ void vvp_fun_delay::recv_real(vvp_net_ptr_t port, double bit,
return;
}
if (initial_) type_ = REAL_DELAY;
else assert(type_ == REAL_DELAY);
vvp_time64_t use_delay;
use_delay = delay_.get_min_delay();
/* Eliminate glitches. */
clean_pulse_events_(use_delay);
if (clean_pulse_events_(use_delay, bit)) return;
/* This must be done after cleaning pulses to avoid propagating
* an incorrect value. */

6
vvp/delay.h
View File

@ -71,6 +71,7 @@ class vvp_delay_t {
*/
class vvp_fun_delay : public vvp_net_fun_t, private vvp_gen_event_s {
enum delay_type_t {UNKNOWN_DELAY, VEC4_DELAY, VEC8_DELAY, REAL_DELAY};
struct event_ {
event_(vvp_time64_t s) : sim_time(s) { }
void (vvp_fun_delay::*run_run_ptr)(struct vvp_fun_delay::event_*cur);
@ -103,6 +104,7 @@ class vvp_fun_delay : public vvp_net_fun_t, private vvp_gen_event_s {
private:
vvp_net_t*net_;
vvp_delay_t delay_;
delay_type_t type_;
bool initial_; // Indicates if the value is still the initial value.
vvp_vector4_t cur_vec4_;
@ -133,6 +135,10 @@ class vvp_fun_delay : public vvp_net_fun_t, private vvp_gen_event_s {
list_->next = cur->next;
return cur;
}
bool clean_pulse_events_(vvp_time64_t use_delay, const vvp_vector4_t&bit);
bool clean_pulse_events_(vvp_time64_t use_delay, const vvp_vector8_t&bit);
bool clean_pulse_events_(vvp_time64_t use_delay, double bit);
// Delete this when done!
void clean_pulse_events_(vvp_time64_t use_delay);
};