23 lines
645 B
Python
23 lines
645 B
Python
from migen.fhdl import structure as f
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class Inst:
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def __init__(self, n):
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self.n = n
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self.bn = f.bits_for(self.n-1)
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f.declare_signal(self, "request", f.BV(self.n))
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f.declare_signal(self, "grant", f.BV(self.bn))
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def get_fragment(self):
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cases = []
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for i in range(self.n):
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switch = []
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for j in reversed(range(i+1,i+self.n)):
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t = j % self.n
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switch = [f.If(self.request[t],
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[f.Assign(self.grant, f.Constant(t, f.BV(self.bn)))],
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switch)]
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case = f.If(~self.request[i], switch)
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cases.append((f.Constant(i, f.BV(self.bn)), case))
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statement = f.Case(self.grant, cases)
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return f.Fragment(sync=[statement])
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