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// Copyright 2023 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.
package test
import (
"encoding/binary"
"testing"
)
var gv = [16]byte{0, 1, 2, 3, 4, 5, 6, 7, 8}
//go:noinline
func readGlobalUnaligned() uint64 {
return binary.LittleEndian.Uint64(gv[1:])
}
func TestUnalignedGlobal(t *testing.T) {
// Note: this is a test not so much of the result of the read, but of
// the correct compilation of that read. On s390x unaligned global
// accesses fail to compile.
if got, want := readGlobalUnaligned(), uint64(0x0807060504030201); got != want {
t.Errorf("read global %x, want %x", got, want)
}
}
func TestSpillOfExtendedEndianLoads(t *testing.T) {
b := []byte{0xaa, 0xbb, 0xcc, 0xdd}
var testCases = []struct {
fn func([]byte) uint64
want uint64
}{
{readUint16le, 0xbbaa},
{readUint16be, 0xaabb},
{readUint32le, 0xddccbbaa},
{readUint32be, 0xaabbccdd},
}
for _, test := range testCases {
if got := test.fn(b); got != test.want {
t.Errorf("got %x, want %x", got, test.want)
}
}
}
func readUint16le(b []byte) uint64 {
y := uint64(binary.LittleEndian.Uint16(b))
nop() // force spill
return y
}
func readUint16be(b []byte) uint64 {
y := uint64(binary.BigEndian.Uint16(b))
nop() // force spill
return y
}
func readUint32le(b []byte) uint64 {
y := uint64(binary.LittleEndian.Uint32(b))
nop() // force spill
return y
}
func readUint32be(b []byte) uint64 {
y := uint64(binary.BigEndian.Uint32(b))
nop() // force spill
return y
}
//go:noinline
func nop() {
}
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