[PATCH v1 5/7] fpu/softfloat: avoid undefined behaviour when normalising empty sigs

[Alex Bennée]

The undefined behaviour checker pointed out that a shift of 64 would
lead to undefined behaviour.

Signed-off-by: Alex Bennée <address@hidden>
---
 fpu/softfloat.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 301ce3b537b..444d35920dd 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -3834,9 +3834,14 @@ void normalizeFloatx80Subnormal(uint64_t aSig, int32_t 
*zExpPtr,
 {
     int8_t shiftCount;
 
-    shiftCount = clz64(aSig);
-    *zSigPtr = aSig<<shiftCount;
-    *zExpPtr = 1 - shiftCount;
+    if (aSig) {
+        shiftCount = clz64(aSig);
+        *zSigPtr = aSig << shiftCount;
+        *zExpPtr = 1 - shiftCount;
+    } else {
+        *zSigPtr = 0;
+        *zExpPtr = 1 - 64;
+    }
 }
 
 /*----------------------------------------------------------------------------
-- 
2.20.1