internal/sm2ec: test loong64

internal/sm2ec/p256_asm_loong64.s

@@ -0,0 +1,53 @@
+// Copyright 2025 Sun Yimin. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+//go:build !purego
+
+#include "textflag.h"
+
+#define res_ptr R29
+#define x_ptr R30
+#define y_ptr R31
+
+#define acc0 R8
+#define acc1 R9
+#define acc2 R10
+#define acc3 R11
+#define acc4 R12
+#define acc5 R13
+
+/* ---------------------------------------*/
+// func p256OrdLittleToBig(res *[32]byte, in *p256OrdElement)
+TEXT ·p256OrdLittleToBig(SB),NOSPLIT,$0
+	JMP ·p256BigToLittle(SB)
+/* ---------------------------------------*/
+// func p256OrdBigToLittle(res *p256OrdElement, in *[32]byte)
+TEXT ·p256OrdBigToLittle(SB),NOSPLIT,$0
+	JMP ·p256BigToLittle(SB)
+/* ---------------------------------------*/
+// func p256LittleToBig(res *[32]byte, in *p256Element)
+TEXT ·p256LittleToBig(SB),NOSPLIT,$0
+	JMP ·p256BigToLittle(SB)
+/* ---------------------------------------*/
+// func p256BigToLittle(res *p256Element, in *[32]byte)
+TEXT ·p256BigToLittle(SB),NOSPLIT,$0
+	MOVV res+0(FP), res_ptr
+	MOVV in+8(FP), x_ptr
+
+	MOVV (8*0)(x_ptr), acc0
+	MOVV (8*1)(x_ptr), acc1
+	MOVV (8*2)(x_ptr), acc2
+	MOVV (8*3)(x_ptr), acc3
+
+	REVBV acc0
+	REVBV acc1
+	REVBV acc2
+	REVBV acc3
+
+	MOVV acc3, (8*0)(res_ptr)
+	MOVV acc2, (8*1)(res_ptr)
+	MOVV acc1, (8*2)(res_ptr)
+	MOVV acc0, (8*3)(res_ptr)
+
+	RET

internal/sm2ec/sm2p256_asm_loong64.go

@@ -0,0 +1,11 @@
+package sm2ec
+
+// p256Element is a P-256 base field element in [0, P-1] in the Montgomery
+// domain (with R 2²⁵⁶) as four limbs in little-endian order value.
+type p256Element [4]uint64
+
+//go:noescape
+func p256BigToLittle(res *p256Element, in *[32]byte)
+
+//go:noescape
+func p256LittleToBig(res *[32]byte, in *p256Element)

internal/sm2ec/sm2p256_asm_loong64_test.go

@@ -0,0 +1,35 @@
+//go:build loong64 && !purego
+
+package sm2ec
+
+import (
+	"bytes"
+	"encoding/binary"
+	"testing"
+)
+
+func TestP256BigToLittle(t *testing.T) {
+	// 构造一个已知的 32 字节大端输入
+	var in [32]byte
+	for i := 0; i < 32; i++ {
+		in[i] = byte(i + 1)
+	}
+	var out p256Element
+
+	p256BigToLittle(&out, &in)
+
+	// 检查每个 limb 是否为小端解包
+	for i := 0; i < 4; i++ {
+		expected := binary.BigEndian.Uint64(in[i*8 : (i+1)*8])
+		if out[i] != expected {
+			t.Errorf("limb %d: got 0x%x, want 0x%x", i, out[i], expected)
+		}
+	}
+
+	// 逆操作测试
+	var back [32]byte
+	p256LittleToBig(&back, &out)
+	if !bytes.Equal(in[:], back[:]) {
+		t.Errorf("p256LittleToBig(p256BigToLittle(...)) mismatch\nin:   %x\nback: %x", in, back)
+	}
+}