Implement almost_full and almost_empty for Synchronous FIFOs #294
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migen/genlib/fifo.py
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| def add_almost_full(self, hi_wm): | ||
| self.almost_full = Signal() | ||
| if hi_wm.bit_count() == 1: | ||
| self.comb += self.almost_full.eq( | ||
| reduce(or_, [level_i for level_i in self.level[log2_int(hi_wm):]])) | ||
| else: | ||
| self.comb += self.almost_full.eq(self.level >= hi_wm) | ||
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| def add_almost_empty(self, lo_wm): | ||
| self.almost_empty = Signal() | ||
| if lo_wm.bit_count() == 1: | ||
| self.comb += self.almost_empty.eq( | ||
| reduce(and_, [~level_i for level_i in self.level[log2_int(lo_wm):]]) | (self.level == lo_wm)) | ||
| else: | ||
| self.comb += self.almost_empty.eq(self.level <= lo_wm) | ||
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I'm not sure what those functions are supposed to do, in any case FIFOInterface isn't a Module and self.comb cannot be used there.
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They are also definitely incorrect in the case of an asynchronous FIFO.
occheung
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Description
This PR introduces FIFO watermark configuration.
almost_fullis asserted.almost_emptyis asserted.