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Added corner case for 1 inv pos polarity and renamed variables.

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This commit is contained in:
Jennifer Eve Sowash
2018-12-07 19:42:11 -08:00
parent a6eec10f41
commit a51aacfa90
2 changed files with 41 additions and 34 deletions
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compiler/pgates/pdriver.py
+34 -29
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@@ -13,25 +13,25 @@ class pdriver(pgate.pgate):
"""
unique_id = 1
def __init__(self, height=None, name="", neg_polarity=False, c_load=8, size_list = []):
def __init__(self, neg_polarity=False, fanout_size=8, size_list = [], height=None, name=""):
self.stage_effort = 4
self.row_height = height
self.height = height
self.neg_polarity = neg_polarity
self.size_list = size_list
self.c_load = c_load
if len(self.size_list) > 0 and (self.c_load != 8 or self.neg_polarity):
raise Exception("Cannot specify both size_list and neg_polarity or c_load.")
self.compute_sizes()
self.fanout_size = fanout_size
if len(self.size_list) > 0 and (self.fanout_size != 8 or self.neg_polarity):
debug.error("Cannot specify both size_list and neg_polarity or fanout_size.", -1)
if name=="":
name = "pdriver_{0}_{1}_".format(self.num_inv, pdriver.unique_id)
pdriver.unique_id += 1
name = "pdriver_{}".format(pdriver.unique_id)
pdriver.unique_id += 1
pgate.pgate.__init__(self, name)
debug.info(1, "Creating {}".format(self.name))
self.compute_sizes()
self.create_netlist()
if not OPTS.netlist_only:
@@ -45,8 +45,8 @@ class pdriver(pgate.pgate):
self.num_inv = len(self.size_list)
else:
# find the number of stages
#c_load is a unit inverter fanout, not a capacitance so c_in=1
num_stages = int(round(log(self.c_load)/log(4)))
#fanout_size is a unit inverter fanout, not a capacitance so c_in=1
num_stages = max(1,int(round(log(self.fanout_size)/log(4))))
# find inv_num and compute sizes
if self.neg_polarity:
@@ -65,30 +65,35 @@ class pdriver(pgate.pgate):
self.calc_size_list = []
self.num_inv = num_stages
# compute sizes
c_prev = self.c_load
fanout_size_prev = self.fanout_size
for x in range(self.num_inv-1,-1,-1):
c_prev = int(round(c_prev/self.stage_effort))
self.calc_size_list.append(c_prev)
fanout_size_prev = int(round(fanout_size_prev/self.stage_effort))
self.calc_size_list.append(fanout_size_prev)
def diff_polarity(self, num_stages):
self.calc_size_list = []
# find which delay is smaller
delay_below = ((num_stages-1)*(self.c_load**(1/num_stages-1))) + num_stages-1
delay_above = ((num_stages+1)*(self.c_load**(1/num_stages+1))) + num_stages+1
if (delay_above < delay_below):
# recompute stage_effort for this delay
if (num_stages > 1):
delay_below = ((num_stages-1)*(self.fanout_size**(1/num_stages-1))) + num_stages-1
delay_above = ((num_stages+1)*(self.fanout_size**(1/num_stages+1))) + num_stages+1
if (delay_above < delay_below):
# recompute stage_effort for this delay
self.num_inv = num_stages+1
polarity_stage_effort = self.fanout_size**(1/self.num_inv)
else:
self.num_inv = num_stages-1
polarity_stage_effort = self.fanout_size**(1/self.num_inv)
else: # num_stages is 1, can't go to 0
self.num_inv = num_stages+1
polarity_stage_effort = self.c_load**(1/self.num_inv)
else:
self.num_inv = num_stages-1
polarity_stage_effort = self.c_load**(1/self.num_inv)
polarity_stage_effort = self.fanout_size**(1/self.num_inv)
# compute sizes
c_prev = self.c_load
fanout_size_prev = self.fanout_size
for x in range(self.num_inv-1,-1,-1):
c_prev = int(round(c_prev/polarity_stage_effort))
self.calc_size_list.append(c_prev)
fanout_size_prev = int(round(fanout_size_prev/polarity_stage_effort))
self.calc_size_list.append(fanout_size_prev)
def create_netlist(self):
@@ -118,11 +123,11 @@ class pdriver(pgate.pgate):
self.inv_list = []
if len(self.size_list) > 0: # size list specified
for x in range(len(self.size_list)):
self.inv_list.append(pinv(size=self.size_list[x], height=self.row_height))
self.inv_list.append(pinv(size=self.size_list[x], height=self.height))
self.add_mod(self.inv_list[x])
else: # find inv sizes
for x in range(len(self.calc_size_list)):
self.inv_list.append(pinv(size=self.calc_size_list[x], height=self.row_height))
self.inv_list.append(pinv(size=self.calc_size_list[x], height=self.height))
self.add_mod(self.inv_list[x])