From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Thu, 21 Feb 2019 09:23:12 +0000 (+0000)
Subject: add comment
X-Git-Tag: ls180-24jan2020~1849
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c21e755b12a7c7c12bf6cfd1f420b19e7bd8ecde;p=ieee754fpu.git

add comment
---

diff --git a/src/add/nmigen_add_experiment.py b/src/add/nmigen_add_experiment.py
index cf0fd92b..bad5fe45 100644
--- a/src/add/nmigen_add_experiment.py
+++ b/src/add/nmigen_add_experiment.py
@@ -38,6 +38,10 @@ class FPGetOpB(FPState):
 class FPAddSpecialCases(FPState):
 
     def action(self, m):
+        """ special cases: NaNs, infs, zeros, denormalised
+            NOTE: some of these are unique to add.  see "Special Operations"
+            https://steve.hollasch.net/cgindex/coding/ieeefloat.html
+        """
         s_nomatch = Signal()
         m.d.comb += s_nomatch.eq(self.a.s != self.b.s)