From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Thu, 14 Feb 2019 14:06:31 +0000 (+0000)
Subject: document guard/round/sticky and tot
X-Git-Tag: ls180-24jan2020~1996
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=80580ea474b77c136f7e588e8dc673407e56a99d;p=ieee754fpu.git

document guard/round/sticky and tot
---

diff --git a/src/add/nmigen_add_experiment.py b/src/add/nmigen_add_experiment.py
index a4525883..5f4642c4 100644
--- a/src/add/nmigen_add_experiment.py
+++ b/src/add/nmigen_add_experiment.py
@@ -102,11 +102,11 @@ class FPADD:
         b = FPNum(self.width)
         z = FPNum(self.width, 24)
 
-        guard = Signal()
-        round_bit = Signal()
-        sticky = Signal()
+        tot = Signal(28)     # sticky/round/guard bits, 23 result, 1 overflow
 
-        tot = Signal(28)
+        guard = Signal()     # tot[2]
+        round_bit = Signal() # tot[1]
+        sticky = Signal()    # tot[0]
 
         with m.FSM() as fsm: