From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sat, 6 Jul 2019 09:51:46 +0000 (+0100)
Subject: pass through exponent extra bits so that normalisation works on 32-to-16 cvt
X-Git-Tag: ls180-24jan2020~908
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=4b48990266d7f00daeb32bd4f833cf99a2862a0e;p=ieee754fpu.git

pass through exponent extra bits so that normalisation works on 32-to-16 cvt
---

diff --git a/src/ieee754/fcvt/pipeline.py b/src/ieee754/fcvt/pipeline.py
index 734f92c8..b72c2551 100644
--- a/src/ieee754/fcvt/pipeline.py
+++ b/src/ieee754/fcvt/pipeline.py
@@ -167,7 +167,7 @@ class FPCVTBasePipe(ControlBase):
     def __init__(self, in_pspec, out_pspec):
         ControlBase.__init__(self)
         self.pipe1 = FPCVTSpecialCasesDeNorm(in_pspec, out_pspec)
-        self.pipe2 = FPNormToPack(out_pspec)
+        self.pipe2 = FPNormToPack(out_pspec, e_extra=True)
 
         self._eqs = self.connect([self.pipe1, self.pipe2])
 
diff --git a/src/ieee754/fpcommon/normtopack.py b/src/ieee754/fpcommon/normtopack.py
index cb4a8bcd..c78c1e95 100644
--- a/src/ieee754/fpcommon/normtopack.py
+++ b/src/ieee754/fpcommon/normtopack.py
@@ -16,14 +16,15 @@ from .pack import FPPackData, FPPackMod
 
 class FPNormToPack(FPState, SimpleHandshake):
 
-    def __init__(self, pspec):
+    def __init__(self, pspec, e_extra=False):
         FPState.__init__(self, "normalise_1")
         print ("normtopack", pspec)
         self.pspec = pspec
+        self.e_extra = e_extra
         SimpleHandshake.__init__(self, self) # pipeline is its own stage
 
     def ispec(self):
-        return FPAddStage1Data(self.pspec)
+        return FPAddStage1Data(self.pspec, e_extra=self.e_extra)
 
     def ospec(self):
         return FPPackData(self.pspec) # FPPackMod
@@ -33,7 +34,7 @@ class FPNormToPack(FPState, SimpleHandshake):
         """
 
         # Normalisation, Rounding Corrections, Pack - in a chain
-        nmod = FPNorm1ModSingle(self.pspec)
+        nmod = FPNorm1ModSingle(self.pspec, e_extra=self.e_extra)
         rmod = FPRoundMod(self.pspec)
         cmod = FPCorrectionsMod(self.pspec)
         pmod = FPPackMod(self.pspec)
diff --git a/src/ieee754/fpcommon/postnormalise.py b/src/ieee754/fpcommon/postnormalise.py
index 58ce1e66..2bf57278 100644
--- a/src/ieee754/fpcommon/postnormalise.py
+++ b/src/ieee754/fpcommon/postnormalise.py
@@ -33,13 +33,14 @@ class FPNorm1Data:
 
 class FPNorm1ModSingle(Elaboratable):
 
-    def __init__(self, pspec):
+    def __init__(self, pspec, e_extra=False):
         self.pspec = pspec
+        self.e_extra = e_extra
         self.i = self.ispec()
         self.o = self.ospec()
 
     def ispec(self):
-        return FPAddStage1Data(self.pspec)
+        return FPAddStage1Data(self.pspec, e_extra=self.e_extra)
 
     def ospec(self):
         return FPNorm1Data(self.pspec)