37 lines
981 B
Python
37 lines
981 B
Python
from migen.fhdl.std import *
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from migen.bus.transactions import *
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def _byte_mask(orig, dat_w, sel):
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r = 0
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shift = 0
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while sel:
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if sel & 1:
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r |= (dat_w & 0xff) << shift
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else:
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r |= (orig & 0xff) << shift
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orig >>= 8
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dat_w >>= 8
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sel >>= 1
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shift += 8
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return r
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class Initiator(Module):
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def __init__(self, generator, mem):
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self.generator = generator
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self.mem = mem
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def do_simulation(self, selfp):
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try:
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transaction = next(self.generator)
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except StopIteration:
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transaction = None
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raise StopSimulation
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if isinstance(transaction, TRead):
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transaction.data = selfp.mem[transaction.address]
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elif isinstance(transaction, TWrite):
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d = selfp.mem[transaction.address]
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d_mask = _byte_mask(d, transaction.data, transaction.sel)
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selfp.mem[transaction.address] = d_mask
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