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62 lines
1.6 KiB
Python
62 lines
1.6 KiB
Python
from collections import OrderedDict
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from amaranth import *
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from amaranth.asserts import *
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from .. import pfv
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__all__ = ["Check"]
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class Check(Elaboratable):
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"""Special Purpose Registers check.
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Checks that reads from supported SPRs are consistent with the last value that was written to
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them.
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"""
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def __init__(self):
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self.pfv = pfv.Interface()
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self.trig = Record([
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("pre", 1),
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("post", 1),
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])
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def elaborate(self, platform):
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m = Module()
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spr_map = OrderedDict()
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for spr_name in ("lr", "ctr", "xer", "tar"):
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spr = Record([
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("written", 1),
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("shadow", 64),
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], name=spr_name)
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spr_map[spr_name] = spr
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spec_order = AnyConst(self.pfv.order.width)
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with m.If(self.pfv.stb & (self.pfv.order <= spec_order)):
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for spr_name, spr in spr_map.items():
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pfv_spr = getattr(self.pfv, spr_name)
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with m.If(pfv_spr.w_stb):
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m.d.sync += [
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spr.written.eq(1),
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spr.shadow .eq(pfv_spr.w_data),
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]
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with m.If(self.trig.post):
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m.d.sync += [
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Assume(Past(self.pfv.stb)),
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Assume(Past(self.pfv.order) == spec_order),
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]
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for spr_name, spr in spr_map.items():
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pfv_spr = getattr(self.pfv, spr_name)
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with m.If(spr.written & Past(pfv_spr.r_stb)):
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m.d.sync += Assert(Past(spr.shadow) == Past(pfv_spr.r_data))
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return m
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