math, math/big: add support for GOARCH=arm64

Change-Id: Ief12e1435a40dd2eaddc3f97f63be44c4dd2e050
Reviewed-on: https://go-review.googlesource.com/7144Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

src/math/abs_arm64.s

+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+TEXT ·Abs(SB),NOSPLIT,$0-16
+	FMOVD	x+0(FP), F3
+	FABSD	F3, F3
+	FMOVD	F3, ret+8(FP)
+	RET

src/math/big/arith_arm64.s

+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+// This file provides fast assembly versions for the elementary
+// arithmetic operations on vectors implemented in arith.go.
+
+TEXT ·mulWW(SB),NOSPLIT,$0
+	B ·mulWW_g(SB)
+
+TEXT ·divWW(SB),NOSPLIT,$0
+	B ·divWW_g(SB)
+
+TEXT ·addVV(SB),NOSPLIT,$0
+	B ·addVV_g(SB)
+
+TEXT ·subVV(SB),NOSPLIT,$0
+	B ·subVV_g(SB)
+
+TEXT ·addVW(SB),NOSPLIT,$0
+	B ·addVW_g(SB)
+
+TEXT ·subVW(SB),NOSPLIT,$0
+	B ·subVW_g(SB)
+
+TEXT ·shlVU(SB),NOSPLIT,$0
+	B ·shlVU_g(SB)
+
+TEXT ·shrVU(SB),NOSPLIT,$0
+	B ·shrVU_g(SB)
+
+TEXT ·mulAddVWW(SB),NOSPLIT,$0
+	B ·mulAddVWW_g(SB)
+
+TEXT ·addMulVVW(SB),NOSPLIT,$0
+	B ·addMulVVW_g(SB)
+
+TEXT ·divWVW(SB),NOSPLIT,$0
+	B ·divWVW_g(SB)
+
+TEXT ·bitLen(SB),NOSPLIT,$0
+	B ·bitLen_g(SB)

src/math/stubs_arm64.s

+// Copyright 2014 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build arm64
+
+#include "textflag.h"
+
+TEXT ·Asin(SB),NOSPLIT,$0
+	B ·asin(SB)
+
+TEXT ·Acos(SB),NOSPLIT,$0
+	B ·acos(SB)
+
+TEXT ·Atan2(SB),NOSPLIT,$0
+	B ·atan2(SB)
+
+TEXT ·Atan(SB),NOSPLIT,$0
+	B ·atan(SB)
+
+TEXT ·Dim(SB),NOSPLIT,$0
+	B ·dim(SB)
+
+TEXT ·Min(SB),NOSPLIT,$0
+	B ·min(SB)
+
+TEXT ·Max(SB),NOSPLIT,$0
+	B ·max(SB)
+
+TEXT ·Exp2(SB),NOSPLIT,$0
+	B ·exp2(SB)
+
+TEXT ·Expm1(SB),NOSPLIT,$0
+	B ·expm1(SB)
+
+TEXT ·Exp(SB),NOSPLIT,$0
+	B ·exp(SB)
+
+TEXT ·Floor(SB),NOSPLIT,$0
+	B ·floor(SB)
+
+TEXT ·Ceil(SB),NOSPLIT,$0
+	B ·ceil(SB)
+
+TEXT ·Trunc(SB),NOSPLIT,$0
+	B ·trunc(SB)
+
+TEXT ·Frexp(SB),NOSPLIT,$0
+	B ·frexp(SB)
+
+TEXT ·Hypot(SB),NOSPLIT,$0
+	B ·hypot(SB)
+
+TEXT ·Ldexp(SB),NOSPLIT,$0
+	B ·ldexp(SB)
+
+TEXT ·Log10(SB),NOSPLIT,$0
+	B ·log10(SB)
+
+TEXT ·Log2(SB),NOSPLIT,$0
+	B ·log2(SB)
+
+TEXT ·Log1p(SB),NOSPLIT,$0
+	B ·log1p(SB)
+
+TEXT ·Log(SB),NOSPLIT,$0
+	B ·log(SB)
+
+TEXT ·Modf(SB),NOSPLIT,$0
+	B ·modf(SB)
+
+TEXT ·Mod(SB),NOSPLIT,$0
+	B ·mod(SB)
+
+TEXT ·Remainder(SB),NOSPLIT,$0
+	B ·remainder(SB)
+
+TEXT ·Sincos(SB),NOSPLIT,$0
+	B ·sincos(SB)
+
+TEXT ·Sin(SB),NOSPLIT,$0
+	B ·sin(SB)
+
+TEXT ·Cos(SB),NOSPLIT,$0
+	B ·cos(SB)
+
+TEXT ·Sqrt(SB),NOSPLIT,$0
+	B ·sqrt(SB)
+
+TEXT ·Tan(SB),NOSPLIT,$0
+	B ·tan(SB)