From: Cesar Strauss <cestrauss@gmail.com>
Date: Fri, 1 Jan 2021 12:59:49 +0000 (-0300)
Subject: Disable data value output on NOP
X-Git-Tag: 24jan2021_ls180~46
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ac0c8772a0e7b487f40af7e9b1ba3f3026a0ebaf;p=soc.git

Disable data value output on NOP
---

diff --git a/src/soc/experiment/alu_hier.py b/src/soc/experiment/alu_hier.py
index c01cc26e..39e9cb92 100644
--- a/src/soc/experiment/alu_hier.py
+++ b/src/soc/experiment/alu_hier.py
@@ -317,11 +317,13 @@ class ALU(Elaboratable):
 
         # choose between zero-delay output, or registered
         with m.If(go_now):
-            m.d.comb += self.o.data.eq(sub.o)
+            with m.If(self.o.ok):
+                m.d.comb += self.o.data.eq(sub.o)
             m.d.comb += self.cr.ok.eq(self.op.rc.rc)
         # only present the result at the last computation cycle
         with m.Elif(alu_done):
-            m.d.comb += self.o.data.eq(alu_r)
+            with m.If(self.o.ok):
+                m.d.comb += self.o.data.eq(alu_r)
             m.d.comb += self.cr.ok.eq(cr_ok_r)
 
         # determine condition register bits based on the data output value