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Applied quick corner estimation to analytical delay.

This commit is contained in:
Hunter Nichols 2019-04-09 12:26:54 -07:00
parent a500d7ee3d
commit c1411f4227
2 changed files with 12 additions and 6 deletions
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16
compiler/base/hierarchy_spice.py
View File

@ -235,13 +235,8 @@ class spice():
modeling it as a resistance driving a capacitance modeling it as a resistance driving a capacitance
""" """
swing_factor = abs(math.log(1-swing)) # time constant based on swing swing_factor = abs(math.log(1-swing)) # time constant based on swing
proc,vdd,temp = corner
#FIXME: type of delay is needed to know which process to use.
proc_mult = max(self.get_process_delay_factor(proc))
volt_mult = self.get_voltage_delay_factor(vdd)
temp_mult = self.get_temp_delay_factor(temp)
delay = swing_factor * r * c #c is in ff and delay is in fs delay = swing_factor * r * c #c is in ff and delay is in fs
delay = delay * proc_mult * volt_mult * temp_mult delay = self.apply_corners_analytically(delay, corner)
delay = delay * 0.001 #make the unit to ps delay = delay * 0.001 #make the unit to ps
# Output slew should be linear to input slew which is described # Output slew should be linear to input slew which is described
@ -254,6 +249,15 @@ class spice():
slew = delay * 0.6 * 2 + 0.005 * slew slew = delay * 0.6 * 2 + 0.005 * slew
return delay_data(delay = delay, slew = slew) return delay_data(delay = delay, slew = slew)
def apply_corners_analytically(self, delay, corner):
"""Multiply delay by corner factors"""
proc,vdd,temp = corner
#FIXME: type of delay is needed to know which process to use.
proc_mult = max(self.get_process_delay_factor(proc))
volt_mult = self.get_voltage_delay_factor(vdd)
temp_mult = self.get_temp_delay_factor(temp)
return delay * proc_mult * volt_mult * temp_mult
def get_process_delay_factor(self, proc): def get_process_delay_factor(self, proc):
"""Returns delay increase estimate based off process """Returns delay increase estimate based off process
Currently does +/-10 for fast/slow corners.""" Currently does +/-10 for fast/slow corners."""

2
compiler/sram_base.py
View File

@ -520,7 +520,9 @@ class sram_base(design, verilog, lef):
wlen_to_dout_delays = self.bank.analytical_delay(corner,slew,load,port) #port should probably be specified... wlen_to_dout_delays = self.bank.analytical_delay(corner,slew,load,port) #port should probably be specified...
all_delays = clk_to_wlen_delays+wlen_to_dout_delays all_delays = clk_to_wlen_delays+wlen_to_dout_delays
total_delay = logical_effort.calculate_absolute_delay(all_delays) total_delay = logical_effort.calculate_absolute_delay(all_delays)
total_delay = self.apply_corners_analytically(total_delay, corner)
last_slew = .1*all_delays[-1].get_absolute_delay() #slew approximated as 10% of delay last_slew = .1*all_delays[-1].get_absolute_delay() #slew approximated as 10% of delay
last_slew = self.apply_corners_analytically(last_slew, corner)
delays[port] = self.return_delay(delay=total_delay, slew=last_slew) delays[port] = self.return_delay(delay=total_delay, slew=last_slew)
return delays return delays