From: Jean THOMAS <git0@pub.jeanthomas.me>
Date: Wed, 24 Jun 2020 08:56:21 +0000 (+0200)
Subject: Simply arbiter when there is only 1 request to arbitrate
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=fea65a4a164e96ed7454627e3aa6fdae4d6c750f;p=gram.git

Simply arbiter when there is only 1 request to arbitrate
---

diff --git a/gram/compat.py b/gram/compat.py
index e049dcd..49ae710 100644
--- a/gram/compat.py
+++ b/gram/compat.py
@@ -52,16 +52,19 @@ class RoundRobin(Elaboratable):
     def elaborate(self, platform):
         m = Module()
 
-        with m.If(self.stb):
-            with m.Switch(self.grant):
-                for i in range(self.n):
-                    with m.Case(i):
-                        for j in reversed(range(i+1, i+self.n)):
-                            # If i+1 <= j < n, then t == j;     (after i)
-                            # If n <= j < i+n, then t == j - n  (before i)
-                            t = j % self.n
-                            with m.If(self.request[t]):
-                                m.d.sync += self.grant.eq(t)
+        if self.n == 1:
+            m.d.comb += self.grant.eq(0)
+        else:
+            with m.If(self.stb):
+                with m.Switch(self.grant):
+                    for i in range(self.n):
+                        with m.Case(i):
+                            for j in reversed(range(i+1, i+self.n)):
+                                # If i+1 <= j < n, then t == j;     (after i)
+                                # If n <= j < i+n, then t == j - n  (before i)
+                                t = j % self.n
+                                with m.If(self.request[t]):
+                                    m.d.sync += self.grant.eq(t)
 
         return m