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dsp/tools: clean up SatAddMixin logic

This commit is contained in:
Robert Jördens 2017-06-21 12:37:11 +02:00
parent f369cb97f7
commit b6569df02f
1 changed files with 9 additions and 6 deletions

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@ -37,9 +37,8 @@ class SatAddMixin:
carry = log2_int(len(a), need_pow2=False)
full = Signal((length + carry, True))
limited = Signal((length, True))
clip = Signal(2)
if clipped is not None:
clipped.eq(clip)
if clipped is None:
clipped = Signal(2)
self.comb += [
full.eq(reduce(add, a)),
]
@ -47,15 +46,19 @@ class SatAddMixin:
self.comb += [
If(full[-1-carry:] == Replicate(full[-1], carry + 1),
limited.eq(full),
clip.eq(0),
clipped.eq(0),
).Else(
limited.eq(Cat(Replicate(~full[-1], length - 1), full[-1])),
clip.eq(Cat(full[-1], ~full[-1])),
clipped.eq(Cat(full[-1], ~full[-1])),
)
]
else:
self.comb += [
clip.eq(Cat(full < limits[0], full > limits[1])),
limited.eq(Array([full, limits[0], limits[1], 0])[clip]),
Case(clip, {
0b01, limited.eq(limits[0]),
0b10, limited.eq(limits[1]),
"default": limited.eq(full),
})
]
return limited