go flags_test 源码
golang flags_test 代码
文件路径：/src/cmd/compile/internal/ssa/flags_test.go
// Copyright 2020 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.
//go:build amd64 || arm64
// +build amd64 arm64
package ssa
// This file tests the functions addFlags64 and subFlags64 by comparing their
// results to what the chip calculates.
import (
"runtime"
"testing"
)
func TestAddFlagsNative(t *testing.T) {
var numbers = []int64{
1, 0, -1,
2, -2,
1<<63 - 1, -1 << 63,
}
coverage := map[flagConstant]bool{}
for _, x := range numbers {
for _, y := range numbers {
a := addFlags64(x, y)
b := flagRegister2flagConstant(asmAddFlags(x, y), false)
if a != b {
t.Errorf("asmAdd diff: x=%x y=%x got=%s want=%s\n", x, y, a, b)
}
coverage[a] = true
}
}
if len(coverage) != 9 { // TODO: can we cover all outputs?
t.Errorf("coverage too small, got %d want 9", len(coverage))
}
}
func TestSubFlagsNative(t *testing.T) {
var numbers = []int64{
1, 0, -1,
2, -2,
1<<63 - 1, -1 << 63,
}
coverage := map[flagConstant]bool{}
for _, x := range numbers {
for _, y := range numbers {
a := subFlags64(x, y)
b := flagRegister2flagConstant(asmSubFlags(x, y), true)
if a != b {
t.Errorf("asmSub diff: x=%x y=%x got=%s want=%s\n", x, y, a, b)
}
coverage[a] = true
}
}
if len(coverage) != 7 { // TODO: can we cover all outputs?
t.Errorf("coverage too small, got %d want 7", len(coverage))
}
}
func TestAndFlagsNative(t *testing.T) {
var numbers = []int64{
1, 0, -1,
2, -2,
1<<63 - 1, -1 << 63,
}
coverage := map[flagConstant]bool{}
for _, x := range numbers {
for _, y := range numbers {
a := logicFlags64(x & y)
b := flagRegister2flagConstant(asmAndFlags(x, y), false)
if a != b {
t.Errorf("asmAnd diff: x=%x y=%x got=%s want=%s\n", x, y, a, b)
}
coverage[a] = true
}
}
if len(coverage) != 3 {
t.Errorf("coverage too small, got %d want 3", len(coverage))
}
}
func asmAddFlags(x, y int64) int
func asmSubFlags(x, y int64) int
func asmAndFlags(x, y int64) int
func flagRegister2flagConstant(x int, sub bool) flagConstant {
var fcb flagConstantBuilder
switch runtime.GOARCH {
case "amd64":
fcb.Z = x>>6&1 != 0
fcb.N = x>>7&1 != 0
fcb.C = x>>0&1 != 0
if sub {
// Convert from amd64-sense to arm-sense
fcb.C = !fcb.C
}
fcb.V = x>>11&1 != 0
case "arm64":
fcb.Z = x>>30&1 != 0
fcb.N = x>>31&1 != 0
fcb.C = x>>29&1 != 0
fcb.V = x>>28&1 != 0
default:
panic("unsupported architecture: " + runtime.GOARCH)
}
return fcb.encode()
}
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