From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Wed, 19 Apr 2017 07:55:19 +0000 (+0200)
Subject: gen/genlib/misc: add BitSlip
X-Git-Tag: 24jan2021_ls180~1872
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f73eb5fe71f61bbd5ce9501b4612caaa87d3bce2;p=litex.git

gen/genlib/misc: add BitSlip
---

diff --git a/litex/gen/genlib/misc.py b/litex/gen/genlib/misc.py
index 42ad878c..a28e30d9 100644
--- a/litex/gen/genlib/misc.py
+++ b/litex/gen/genlib/misc.py
@@ -86,3 +86,19 @@ class WaitTimer(Module):
             If(self.wait,
                 If(~self.done, count.eq(count - 1))
             ).Else(count.eq(count.reset))
+
+
+class BitSlip(Module):
+    def __init__(self, dw):
+        self.i = Signal(dw)
+        self.o = Signal(dw)
+        self.value = Signal(max=dw)
+
+        # # #
+
+        r = Signal(2*dw)
+        self.sync += r.eq(Cat(r[dw:], self.i))
+        cases = {}
+        for i in range(dw):
+            cases[i] = self.o.eq(r[i:dw+i])
+        self.sync += Case(self.value, cases)