if fa.Type != machoType {
				return nil, &FormatError{offset, fmt.Sprintf("Mach-O type for architecture #%d (type=%#x) does not match first (type=%#x)", i, fa.Type, machoType), nil}
			}
		}

		ff.Arches = append(ff.Arches, fa)
	}

	return &ff, nil
}

// OpenFat opens the named file using [os.Open] and prepares it for use as a Mach-O
// universal binary.
func OpenFat(name string) (*FatFile, error) {

		&asmArchS390X,
		&asmArchWasm,
		&asmArchLoong64,
	}
)

func init() {
	for _, arch := range arches {
		arch.sizes = types.SizesFor("gc", arch.name)
		if arch.sizes == nil {
			// TODO(adonovan): fix: now that asmdecl is not in the standard
			// library we cannot assume types.SizesFor is consistent with arches.
			// For now, assume 64-bit norms and print a warning.

	case "ppc64", "ppc64le":
		arch = macho.CpuPpc64
	default:
		return nil, fmt.Errorf("unsupported host architecture for %s: %s", name, runtime.GOARCH)
	}
	for i := range of.Arches {
		if of.Arches[i].Cpu == arch {
			return b.openMachOCommon(name, of.Arches[i].File, start, limit, offset)
		}
	}
	return nil, fmt.Errorf("architecture not found in %s: %s", name, runtime.GOARCH)
}

// register space otherwise.
type RegArgs struct {
	// Values in these slots should be precisely the bit-by-bit
	// representation of how they would appear in a register.
	//
	// This means that on big endian arches, integer values should
	// be in the top bits of the slot. Floats are usually just
	// directly represented, but some architectures treat narrow
	// width floating point values specially (e.g. they're promoted

func main() {
	flag.Parse()
	if flag.NArg() > 0 {
		out = os.Stdout
		for _, arch := range flag.Args() {
			gen, ok := arches[arch]
			if !ok {
				log.Fatalf("unknown arch %s", arch)
			}
			header(arch)
			gen()
		}
		return
	}

	for arch, gen := range arches {
		f, err := os.Create(fmt.Sprintf("preempt_%s.s", arch))
		if err != nil {
			log.Fatal(err)
		}
		out = f
		header(arch)

	case bytes.HasPrefix(ident, []byte("\xCA\xFE\xBA\xBE")) || bytes.HasPrefix(ident, []byte("\xCA\xFE\xBA\xBF")):
		f, err := macho.NewFatFile(r)
		if err != nil || len(f.Arches) == 0 {
			return "", "", errUnrecognizedFormat
		}
		x = &machoExe{f.Arches[0].File}
	case bytes.HasPrefix(ident, []byte{0x01, 0xDF}) || bytes.HasPrefix(ident, []byte{0x01, 0xF7}):
		f, err := xcoff.NewFile(r)
		if err != nil {

			// Create the build environments corresponding the above specifiers
			envs := make([]buildEnv, 0, 4)
			arches := []string{arch}
			// ppc64x is a pseudo-arch, generate tests for both endian variants.
			if arch == "ppc64x" {
				arches = []string{"ppc64", "ppc64le"}
			}
			for _, arch := range arches {
				if subarch != "" {
					envs = append(envs, buildEnv(os+"/"+arch+"/"+subarch))
				} else {

// https://golang.org/issue/37238
func TestGdbInfCallstack(t *testing.T) {
	checkGdbEnvironment(t)

	testenv.MustHaveCGO(t)
	if runtime.GOARCH != "arm64" {
		t.Skip("skipping infinite callstack test on non-arm64 arches")
	}

	t.Parallel()
	checkGdbVersion(t)

	dir := t.TempDir()

	// Build the source code.
	src := filepath.Join(dir, "main.go")
	err := os.WriteFile(src, []byte(InfCallstackSource), 0644)

			}

			// Flow backwards from the control value to find the
			// flag load. We don't know what lowered ops we're
			// looking for, but all current arches produce a
			// single op that does the memory load from the flag
			// address, so we look for that.
			var load *ssa.Value
			v := decisionBlock.Controls[0]
			for {
				if v.MemoryArg() != nil {

	MOVD	g_m(g), R3
	MOVD	m_curg(R3), g
	BL	runtime·save_g(SB)
	MOVD	(g_sched+gobuf_sp)(g), R1
	MOVD	R0, (g_sched+gobuf_sp)(g)
	RET

noswitch:
	// already on m stack, just call directly
	// On other arches we do a tail call here, but it appears to be
	// impossible to tail call a function pointer in shared mode on
	// ppc64 because the caller is responsible for restoring the TOC.
	MOVD	0(R11), R12	// code pointer
	MOVD	R12, CTR