From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Tue, 23 Jul 2019 16:44:32 +0000 (+0100)
Subject: specialcases: sqrt of -ve zero is -ve zero
X-Git-Tag: ls180-24jan2020~745
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=166d85d572afb1a359d0b17ce9c11029280b2b95;p=ieee754fpu.git

specialcases: sqrt of -ve zero is -ve zero
---

diff --git a/src/ieee754/fpdiv/specialcases.py b/src/ieee754/fpdiv/specialcases.py
index 62873026..3b634bf3 100644
--- a/src/ieee754/fpdiv/specialcases.py
+++ b/src/ieee754/fpdiv/specialcases.py
@@ -104,8 +104,13 @@ class FPDIVSpecialCasesMod(Elaboratable):
 
         with m.If(self.i.ctx.op == 1): # SQRT
 
+            # if a is zero return zero
+            with m.If(a1.is_zero):
+                m.d.comb += self.o.out_do_z.eq(1)
+                m.d.comb += self.o.z.zero(a1.s)
+
             # -ve number is NaN
-            with m.If(a1.s):
+            with m.Elif(a1.s):
                 m.d.comb += self.o.out_do_z.eq(1)
                 m.d.comb += self.o.z.nan(0)
 
@@ -119,11 +124,6 @@ class FPDIVSpecialCasesMod(Elaboratable):
                 m.d.comb += self.o.out_do_z.eq(1)
                 m.d.comb += self.o.z.nan(0)
 
-            # if a is zero return zero
-            with m.Elif(a1.is_zero):
-                m.d.comb += self.o.out_do_z.eq(1)
-                m.d.comb += self.o.z.zero(0)
-
             # Denormalised Number checks next, so pass a/b data through
             with m.Else():
                 m.d.comb += self.o.out_do_z.eq(0)