From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 22 Apr 2019 20:58:26 +0000 (+0100)
Subject: comment about max_exponent, remove its use: use python slice [:-1]
X-Git-Tag: div_pipeline~2147
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d7d4d8c2219412a45f6f860cdc62d325a446bb36;p=soc.git

comment about max_exponent, remove its use: use python slice [:-1]
slice [:-1] is the python way to not need explicit length
it is already in self.state, so no need to do self.max_exponent-1
just use -1
---

diff --git a/TLB/src/LFSR.py b/TLB/src/LFSR.py
index c850d5fb..d0c63227 100644
--- a/TLB/src/LFSR.py
+++ b/TLB/src/LFSR.py
@@ -70,7 +70,8 @@ class LFSR(LFSRPolynomial):
 
             Outputs:
             -------
-            :state: the LFSR state.  length is taken from the polynomial
+            :state: the LFSR state.  bitwidth is taken from the polynomial
+                    maximum exponent.
 
             Note: if an LFSRPolynomial is passed in as the input, because
             LFSRPolynomial is derived from set() it's ok:
@@ -95,7 +96,7 @@ class LFSR(LFSRPolynomial):
         # if enabled, shift-and-feedback
         with m.If(self.enable):
             # shift up lower bits by Cat'ing in a new bit zero (feedback)
-            newstate = Cat(feedback, self.state[0:self.max_exponent - 1])
+            newstate = Cat(feedback, self.state[:-1])
             m.d.sync += self.state.eq(newstate)
 
         return m