From c0b4a7b25430e4495bb213a5c3ad43e26c6bff20 Mon Sep 17 00:00:00 2001
From: Ruinland ChuanTzu Tsai <ruinland@andestech.com>
Date: Mon, 2 Dec 2019 19:06:52 +0800
Subject: [PATCH] riscv64: fix fesetenv(FE_DFL_ENV) crash

When FE_DFL_ENV is passed to fesetenv(), the very first instruction
lw t1, 0(a0) will fail since a0 is -1.
---
 src/fenv/riscv64/fenv.S | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/fenv/riscv64/fenv.S b/src/fenv/riscv64/fenv.S
index f149003d..0ea78bf9 100644
--- a/src/fenv/riscv64/fenv.S
+++ b/src/fenv/riscv64/fenv.S
@@ -45,8 +45,11 @@ fegetenv:
 .global fesetenv
 .type fesetenv, %function
 fesetenv:
+	li t2, -1
+	li t1, 0
+	beq a0, t2, 1f
 	lw t1, 0(a0)
-	fscsr t0, t1
+1:	fscsr t1
 	li a0, 0
 	ret
 
-- 
2.25.1