From 1ac832509f2ea1b566f0c06f98f308f58b03d098 Mon Sep 17 00:00:00 2001
From: Vincent Chen <vincentc@andestech.com>
Date: Thu, 22 Nov 2018 11:14:35 +0800
Subject: nds32: Support FP emulation

The Andes FPU coprocessor does not support denormalized number handling.
According to the specification, FPU generates a denorm input exception
that requires the kernel to deal with this instrution operation when it
encounters denormalized operands. Hence an nds32 FPU ISA emulator in the
kernel is required to meet requirement.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Nickhu <nickhu@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
---
 arch/nds32/math-emu/fnegs.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 arch/nds32/math-emu/fnegs.c

(limited to 'arch/nds32/math-emu/fnegs.c')

diff --git a/arch/nds32/math-emu/fnegs.c b/arch/nds32/math-emu/fnegs.c
new file mode 100644
index 000000000000..07270b326a77
--- /dev/null
+++ b/arch/nds32/math-emu/fnegs.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2018 Andes Technology Corporation
+#include <linux/uaccess.h>
+
+#include <asm/sfp-machine.h>
+#include <math-emu/soft-fp.h>
+#include <math-emu/single.h>
+void fnegs(void *ft, void *fa)
+{
+	FP_DECL_S(A);
+	FP_DECL_S(R);
+	FP_DECL_EX;
+
+	FP_UNPACK_SP(A, fa);
+
+	FP_NEG_S(R, A);
+
+	FP_PACK_SP(ft, R);
+
+	__FPU_FPCSR |= FP_CUR_EXCEPTIONS;
+}
-- 
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