From ede69959e4db5e47c28034005db3f2b5c75e8a03 Mon Sep 17 00:00:00 2001
From: chenqiuhao <haohao0924@126.com>
Date: Fri, 26 Oct 2018 15:03:20 +0800
Subject: [PATCH] debug for compare exchange

---
 kernel/src/arch/riscv32/compiler_rt.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/src/arch/riscv32/compiler_rt.rs b/kernel/src/arch/riscv32/compiler_rt.rs
index aaf9be0c..63752c9a 100644
--- a/kernel/src/arch/riscv32/compiler_rt.rs
+++ b/kernel/src/arch/riscv32/compiler_rt.rs
@@ -56,7 +56,13 @@ unsafe fn __atomic_compare_exchange<T: PartialEq>(dst: *mut T, expected: *mut T,
     let flags = interrupt::disable_and_store();
     let val = read(dst);
     let success = val == read(expected);
-    write(dst, if success {desired} else {val});
+    if success {
+        write(dst, desired);
+        write(expected, val);
+    } else {
+        write(expected, val);
+    }
+    
     interrupt::restore(flags);
     success
 }