math, math/big: add support for GOARCH=mips{,le}

Change-Id: I54e100cced5b49674937fb87d1e0f585f962aeb7
Reviewed-on: https://go-review.googlesource.com/31484Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/math/big/arith_mipsx.s

+// Copyright 2016 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 !math_big_pure_go,mips !math_big_pure_go,mipsle
+
+#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
+	JMP	·mulWW_g(SB)
+
+TEXT ·divWW(SB),NOSPLIT,$0
+	JMP	·divWW_g(SB)
+
+TEXT ·addVV(SB),NOSPLIT,$0
+	JMP	·addVV_g(SB)
+
+TEXT ·subVV(SB),NOSPLIT,$0
+	JMP	·subVV_g(SB)
+
+TEXT ·addVW(SB),NOSPLIT,$0
+	JMP	·addVW_g(SB)
+
+TEXT ·subVW(SB),NOSPLIT,$0
+	JMP	·subVW_g(SB)
+
+TEXT ·shlVU(SB),NOSPLIT,$0
+	JMP	·shlVU_g(SB)
+
+TEXT ·shrVU(SB),NOSPLIT,$0
+	JMP	·shrVU_g(SB)
+
+TEXT ·mulAddVWW(SB),NOSPLIT,$0
+	JMP	·mulAddVWW_g(SB)
+
+TEXT ·addMulVVW(SB),NOSPLIT,$0
+	JMP	·addMulVVW_g(SB)
+
+TEXT ·divWVW(SB),NOSPLIT,$0
+	JMP	·divWVW_g(SB)
+
+TEXT ·bitLen(SB),NOSPLIT,$0
+	JMP	·bitLen_g(SB)

src/math/sqrt_mipsx.s

+// Copyright 2016 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 mips mipsle
+
+#include "textflag.h"
+
+// func Sqrt(x float64) float64
+TEXT ·Sqrt(SB),NOSPLIT,$0
+	MOVD	x+0(FP), F0
+	SQRTD	F0, F0
+	MOVD	F0, ret+8(FP)
+	RET

src/math/stubs_mipsx.s

+// Copyright 2016 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 mips mipsle
+
+#include "textflag.h"
+
+TEXT ·Asin(SB),NOSPLIT,$0
+	JMP	·asin(SB)
+
+TEXT ·Acos(SB),NOSPLIT,$0
+	JMP	·acos(SB)
+
+TEXT ·Atan2(SB),NOSPLIT,$0
+	JMP	·atan2(SB)
+
+TEXT ·Atan(SB),NOSPLIT,$0
+	JMP	·atan(SB)
+
+TEXT ·Dim(SB),NOSPLIT,$0
+	JMP	·dim(SB)
+
+TEXT ·Min(SB),NOSPLIT,$0
+	JMP	·min(SB)
+
+TEXT ·Max(SB),NOSPLIT,$0
+	JMP	·max(SB)
+
+TEXT ·Exp2(SB),NOSPLIT,$0
+	JMP	·exp2(SB)
+
+TEXT ·Expm1(SB),NOSPLIT,$0
+	JMP	·expm1(SB)
+
+TEXT ·Exp(SB),NOSPLIT,$0
+	JMP	·exp(SB)
+
+TEXT ·Floor(SB),NOSPLIT,$0
+	JMP	·floor(SB)
+
+TEXT ·Ceil(SB),NOSPLIT,$0
+	JMP	·ceil(SB)
+
+TEXT ·Trunc(SB),NOSPLIT,$0
+	JMP	·trunc(SB)
+
+TEXT ·Frexp(SB),NOSPLIT,$0
+	JMP	·frexp(SB)
+
+TEXT ·Hypot(SB),NOSPLIT,$0
+	JMP	·hypot(SB)
+
+TEXT ·Ldexp(SB),NOSPLIT,$0
+	JMP	·ldexp(SB)
+
+TEXT ·Log10(SB),NOSPLIT,$0
+	JMP	·log10(SB)
+
+TEXT ·Log2(SB),NOSPLIT,$0
+	JMP	·log2(SB)
+
+TEXT ·Log1p(SB),NOSPLIT,$0
+	JMP	·log1p(SB)
+
+TEXT ·Log(SB),NOSPLIT,$0
+	JMP	·log(SB)
+
+TEXT ·Modf(SB),NOSPLIT,$0
+	JMP	·modf(SB)
+
+TEXT ·Mod(SB),NOSPLIT,$0
+	JMP	·mod(SB)
+
+TEXT ·Remainder(SB),NOSPLIT,$0
+	JMP	·remainder(SB)
+
+TEXT ·Sincos(SB),NOSPLIT,$0
+	JMP	·sincos(SB)
+
+TEXT ·Sin(SB),NOSPLIT,$0
+	JMP	·sin(SB)
+
+TEXT ·Cos(SB),NOSPLIT,$0
+	JMP	·cos(SB)
+
+TEXT ·Tan(SB),NOSPLIT,$0
+	JMP	·tan(SB)