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40 lines
944 B
Python
40 lines
944 B
Python
from __future__ import generators
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from myhdl import Signal, intbv, concat
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from arith_utils import BEHAVIOR
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from PrefixAnd import PrefixAnd
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def Dec(width, speed, A, Z, architecture=BEHAVIOR):
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""" Decrementer module.
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width -- bitwidth of input and output
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speed -- SLOW, MEDIUM, or FAST performance
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A -- input
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Z -- output
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architecture -- BEHAVIOR or STRUCTURE architecture selection
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"""
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def Behavioral():
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while 1:
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yield A
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Z.next = A - 1
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def Structural():
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AI = Signal(intbv(0))
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PO = Signal(intbv(0))
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prefix = PrefixAnd(width, speed, AI, PO)
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def logic():
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while 1:
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yield A, PO
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AI.next = ~A
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Z.next = A ^ concat(PO[width-1:], '1')
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return [prefix, logic()]
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if architecture == BEHAVIOR:
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return Behavioral()
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else:
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return Structural()
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