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corelogic/roundrobin: handle correctly special case with 1 request source

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This commit is contained in:
Sebastien Bourdeauducq 2012-03-31 18:01:40 +02:00
parent 94b02aa8ed
commit 0dfc215fe8
1 changed files with 24 additions and 21 deletions
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45
migen/corelogic/roundrobin.py
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@ -13,24 +13,27 @@ class RoundRobin:
self.ce = Signal() self.ce = Signal()
def get_fragment(self): def get_fragment(self):
cases = [] if self.n > 1:
for i in range(self.n): cases = []
switch = [] for i in range(self.n):
for j in reversed(range(i+1,i+self.n)): switch = []
t = j % self.n for j in reversed(range(i+1,i+self.n)):
switch = [ t = j % self.n
If(self.request[t], switch = [
self.grant.eq(Constant(t, BV(self.bn))) If(self.request[t],
).Else( self.grant.eq(Constant(t, BV(self.bn)))
*switch ).Else(
) *switch
] )
if self.switch_policy == SP_WITHDRAW: ]
case = [If(~self.request[i], *switch)] if self.switch_policy == SP_WITHDRAW:
else: case = [If(~self.request[i], *switch)]
case = switch else:
cases.append([Constant(i, BV(self.bn))] + case) case = switch
statement = Case(self.grant, *cases) cases.append([Constant(i, BV(self.bn))] + case)
if self.switch_policy == SP_CE: statement = Case(self.grant, *cases)
statement = If(self.ce, statement) if self.switch_policy == SP_CE:
return Fragment(sync=[statement]) statement = If(self.ce, statement)
return Fragment(sync=[statement])
else:
return Fragment([self.grant.eq(0)])