Implement almost_full and almost_empty for Synchronous FIFOs #294
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
migen/genlib/fifo.py
Outdated
Comment on lines
85
to
100
| 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) | ||
|
|
||
| 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) | ||
|
|
There was a problem hiding this comment.
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.
There was a problem hiding this comment.
They are also definitely incorrect in the case of an asynchronous FIFO.
occheung
force-pushed
the
fifo-watermark
branch
from
573e4cc to
a960a08
Compare
migen/genlib/fifo.py
Outdated
Comment on lines
155
to
157
| 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):]])) |
There was a problem hiding this comment.
Isn't Vivado handling this already?
occheung
force-pushed
the
fifo-watermark
branch
from
a960a08 to
cadfd24
Compare
occheung
force-pushed
the
fifo-watermark
branch
from
cadfd24 to
1694a08
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
This PR introduces FIFO watermark configuration.
almost_fullis asserted.almost_emptyis asserted.