From bb41b209a6de5c0d9338a640c144dadc9b719f59 Mon Sep 17 00:00:00 2001
From: David Craven <david@craven.ch>
Date: Mon, 20 Nov 2017 14:14:01 +0100
Subject: [PATCH] Read bits only once.

---
 src/csr.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/csr.rs b/src/csr.rs
index 43f6ea8..07214e0 100644
--- a/src/csr.rs
+++ b/src/csr.rs
@@ -283,8 +283,9 @@ impl mcause::R {
     #[inline(always)]
     /// Trap Cause
     pub fn cause(&self) -> Trap {
-        let code = self.bits() & !(1 << 31);
-        match self.bits() & (1 << 31) == 1 << 31 {
+        let bits = self.bits();
+        let code = bits & !(1 << 31);
+        match bits & (1 << 31) == 1 << 31 {
             true => Trap::Interrupt(Interrupt::from(code)),
             false => Trap::Exception(Exception::from(code)),
         }