cmd: add golang.org/x/arch/ppc64/ppc64asm for disassembly

For #9039.

Change-Id: I2b1bcd76857ff332411ca21a0cc5def3097a8eaf
Reviewed-on: https://go-review.googlesource.com/30936
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

misc/nacl/testzip.proto

@@ -48,6 +48,10 @@ go	src=..
 								x86asm
 									testdata
 										+
+							ppc64
+								ppc64asm
+									testdata
+										+
 		archive
 			tar
 				testdata

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/decode.go

+// Copyright 2014 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 ppc64asm
+
+import (
+	"encoding/binary"
+	"fmt"
+	"log"
+)
+
+const debugDecode = false
+
+// instFormat is a decoding rule for one specific instruction form.
+// a uint32 instruction ins matches the rule if ins&Mask == Value
+// DontCare bits should be zero, but the machine might not reject
+// ones in those bits, they are mainly reserved for future expansion
+// of the instruction set.
+// The Args are stored in the same order as the instruction manual.
+type instFormat struct {
+	Op       Op
+	Mask     uint32
+	Value    uint32
+	DontCare uint32
+	Args     [5]*argField
+}
+
+// argField indicate how to decode an argument to an instruction.
+// First parse the value from the BitFields, shift it left by Shift
+// bits to get the actual numerical value.
+type argField struct {
+	Type  ArgType
+	Shift uint8
+	BitFields
+}
+
+// Parse parses the Arg out from the given binary instruction i.
+func (a argField) Parse(i uint32) Arg {
+	switch a.Type {
+	default:
+		return nil
+	case TypeUnknown:
+		return nil
+	case TypeReg:
+		return R0 + Reg(a.BitFields.Parse(i))
+	case TypeCondRegBit:
+		return Cond0LT + CondReg(a.BitFields.Parse(i))
+	case TypeCondRegField:
+		return CR0 + CondReg(a.BitFields.Parse(i))
+	case TypeFPReg:
+		return F0 + Reg(a.BitFields.Parse(i))
+	case TypeVecReg:
+		return V0 + Reg(a.BitFields.Parse(i))
+	case TypeSpReg:
+		return SpReg(a.BitFields.Parse(i))
+	case TypeImmSigned:
+		return Imm(a.BitFields.ParseSigned(i) << a.Shift)
+	case TypeImmUnsigned:
+		return Imm(a.BitFields.Parse(i) << a.Shift)
+	case TypePCRel:
+		return PCRel(a.BitFields.ParseSigned(i) << a.Shift)
+	case TypeLabel:
+		return Label(a.BitFields.ParseSigned(i) << a.Shift)
+	case TypeOffset:
+		return Offset(a.BitFields.ParseSigned(i) << a.Shift)
+	}
+}
+
+type ArgType int8
+
+const (
+	TypeUnknown      ArgType = iota
+	TypePCRel                // PC-relative address
+	TypeLabel                // absolute address
+	TypeReg                  // integer register
+	TypeCondRegBit           // conditional register bit (0-31)
+	TypeCondRegField         // conditional register field (0-7)
+	TypeFPReg                // floating point register
+	TypeVecReg               // vector register
+	TypeSpReg                // special register (depends on Op)
+	TypeImmSigned            // signed immediate
+	TypeImmUnsigned          // unsigned immediate/flag/mask, this is the catch-all type
+	TypeOffset               // signed offset in load/store
+	TypeLast                 // must be the last one
+)
+
+func (t ArgType) String() string {
+	switch t {
+	default:
+		return fmt.Sprintf("ArgType(%d)", int(t))
+	case TypeUnknown:
+		return "Unknown"
+	case TypeReg:
+		return "Reg"
+	case TypeCondRegBit:
+		return "CondRegBit"
+	case TypeCondRegField:
+		return "CondRegField"
+	case TypeFPReg:
+		return "FPReg"
+	case TypeVecReg:
+		return "VecReg"
+	case TypeSpReg:
+		return "SpReg"
+	case TypeImmSigned:
+		return "ImmSigned"
+	case TypeImmUnsigned:
+		return "ImmUnsigned"
+	case TypePCRel:
+		return "PCRel"
+	case TypeLabel:
+		return "Label"
+	case TypeOffset:
+		return "Offset"
+	}
+}
+
+func (t ArgType) GoString() string {
+	s := t.String()
+	if t > 0 && t < TypeLast {
+		return "Type" + s
+	}
+	return s
+}
+
+var (
+	// Errors
+	errShort   = fmt.Errorf("truncated instruction")
+	errUnknown = fmt.Errorf("unknown instruction")
+)
+
+var decoderCover []bool
+
+// Decode decodes the leading bytes in src as a single instruction using
+// byte order ord.
+func Decode(src []byte, ord binary.ByteOrder) (inst Inst, err error) {
+	if len(src) < 4 {
+		return inst, errShort
+	}
+	if decoderCover == nil {
+		decoderCover = make([]bool, len(instFormats))
+	}
+	inst.Len = 4 // only 4-byte instructions are supported
+	ui := ord.Uint32(src[:inst.Len])
+	inst.Enc = ui
+	for i, iform := range instFormats {
+		if ui&iform.Mask != iform.Value {
+			continue
+		}
+		if ui&iform.DontCare != 0 {
+			if debugDecode {
+				log.Printf("Decode(%#x): unused bit is 1 for Op %s", ui, iform.Op)
+			}
+			// to match GNU objdump (libopcodes), we ignore don't care bits
+		}
+		for i, argfield := range iform.Args {
+			if argfield == nil {
+				break
+			}
+			inst.Args[i] = argfield.Parse(ui)
+		}
+		inst.Op = iform.Op
+		if debugDecode {
+			log.Printf("%#x: search entry %d", ui, i)
+			continue
+		}
+		break
+	}
+	if inst.Op == 0 {
+		return inst, errUnknown
+	}
+	return inst, nil
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/decode_test.go

+// Copyright 2014 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 ppc64asm
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+	"io/ioutil"
+	"strings"
+	"testing"
+)
+
+func TestDecode(t *testing.T) {
+	data, err := ioutil.ReadFile("testdata/decode.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	all := string(data)
+	for strings.Contains(all, "\t\t") {
+		all = strings.Replace(all, "\t\t", "\t", -1)
+	}
+	for _, line := range strings.Split(all, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		f := strings.SplitN(line, "\t", 3)
+		i := strings.Index(f[0], "|")
+		if i < 0 {
+			t.Errorf("parsing %q: missing | separator", f[0])
+			continue
+		}
+		if i%2 != 0 {
+			t.Errorf("parsing %q: misaligned | separator", f[0])
+		}
+		size := i / 2
+		code, err := hex.DecodeString(f[0][:i] + f[0][i+1:])
+		if err != nil {
+			t.Errorf("parsing %q: %v", f[0], err)
+			continue
+		}
+		syntax, asm := f[1], f[2]
+		inst, err := Decode(code, binary.BigEndian)
+		var out string
+		if err != nil {
+			out = "error: " + err.Error()
+		} else {
+			switch syntax {
+			case "gnu":
+				out = GNUSyntax(inst)
+			//case "plan9":
+			//	out = GoSyntax(inst, 0, nil, nil)
+			default:
+				t.Errorf("unknown syntax %q", syntax)
+				continue
+			}
+		}
+		if out != asm || inst.Len != size {
+			t.Errorf("Decode(%s) [%s] = %s want %s", f[0], syntax, out, asm)
+		}
+	}
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/doc.go

+// Copyright 2014 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 ppc64asm implements decoding of 64-bit PowerPC machine code.
+package ppc64asm

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/ext_test.go

+// Copyright 2014 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.
+
+// Support for testing against external disassembler program.
+// Copied and simplified from rsc.io/arm/armasm/ext_test.go.
+
+package ppc64asm
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
+	"encoding/hex"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"math/rand"
+	"os"
+	"os/exec"
+	"regexp"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+)
+
+var (
+	printTests = flag.Bool("printtests", false, "print test cases that exercise new code paths")
+	dumpTest   = flag.Bool("dump", false, "dump all encodings")
+	mismatch   = flag.Bool("mismatch", false, "log allowed mismatches")
+	longTest   = flag.Bool("long", false, "long test")
+	keep       = flag.Bool("keep", false, "keep object files around")
+	debug      = false
+)
+
+// A ExtInst represents a single decoded instruction parsed
+// from an external disassembler's output.
+type ExtInst struct {
+	addr uint32
+	enc  [4]byte
+	nenc int
+	text string
+}
+
+func (r ExtInst) String() string {
+	return fmt.Sprintf("%#x: % x: %s", r.addr, r.enc, r.text)
+}
+
+// An ExtDis is a connection between an external disassembler and a test.
+type ExtDis struct {
+	Dec      chan ExtInst
+	File     *os.File
+	Size     int
+	KeepFile bool
+	Cmd      *exec.Cmd
+}
+
+// Run runs the given command - the external disassembler - and returns
+// a buffered reader of its standard output.
+func (ext *ExtDis) Run(cmd ...string) (*bufio.Reader, error) {
+	if *keep {
+		log.Printf("%s\n", strings.Join(cmd, " "))
+	}
+	ext.Cmd = exec.Command(cmd[0], cmd[1:]...)
+	out, err := ext.Cmd.StdoutPipe()
+	if err != nil {
+		return nil, fmt.Errorf("stdoutpipe: %v", err)
+	}
+	if err := ext.Cmd.Start(); err != nil {
+		return nil, fmt.Errorf("exec: %v", err)
+	}
+
+	b := bufio.NewReaderSize(out, 1<<20)
+	return b, nil
+}
+
+// Wait waits for the command started with Run to exit.
+func (ext *ExtDis) Wait() error {
+	return ext.Cmd.Wait()
+}
+
+// testExtDis tests a set of byte sequences against an external disassembler.
+// The disassembler is expected to produce the given syntax and be run
+// in the given architecture mode (16, 32, or 64-bit).
+// The extdis function must start the external disassembler
+// and then parse its output, sending the parsed instructions on ext.Dec.
+// The generate function calls its argument f once for each byte sequence
+// to be tested. The generate function itself will be called twice, and it must
+// make the same sequence of calls to f each time.
+// When a disassembly does not match the internal decoding,
+// allowedMismatch determines whether this mismatch should be
+// allowed, or else considered an error.
+func testExtDis(
+	t *testing.T,
+	syntax string,
+	extdis func(ext *ExtDis) error,
+	generate func(f func([]byte)),
+	allowedMismatch func(text string, size int, inst *Inst, dec ExtInst) bool,
+) {
+	start := time.Now()
+	ext := &ExtDis{
+		Dec: make(chan ExtInst),
+	}
+	errc := make(chan error)
+
+	// First pass: write instructions to input file for external disassembler.
+	file, f, size, err := writeInst(generate)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ext.Size = size
+	ext.File = f
+	defer func() {
+		f.Close()
+		if !*keep {
+			os.Remove(file)
+		}
+	}()
+
+	// Second pass: compare disassembly against our decodings.
+	var (
+		totalTests  = 0
+		totalSkips  = 0
+		totalErrors = 0
+
+		errors = make([]string, 0, 100) // sampled errors, at most cap
+	)
+	go func() {
+		errc <- extdis(ext)
+	}()
+	generate(func(enc []byte) {
+		dec, ok := <-ext.Dec
+		if !ok {
+			t.Errorf("decoding stream ended early")
+			return
+		}
+		inst, text := disasm(syntax, pad(enc))
+		totalTests++
+		if *dumpTest {
+			fmt.Printf("%x -> %s [%d]\n", enc[:len(enc)], dec.text, dec.nenc)
+		}
+		if text != dec.text || inst.Len != dec.nenc {
+			suffix := ""
+			if allowedMismatch(text, size, &inst, dec) {
+				totalSkips++
+				if !*mismatch {
+					return
+				}
+				suffix += " (allowed mismatch)"
+			}
+			totalErrors++
+			if len(errors) >= cap(errors) {
+				j := rand.Intn(totalErrors)
+				if j >= cap(errors) {
+					return
+				}
+				errors = append(errors[:j], errors[j+1:]...)
+			}
+			errors = append(errors, fmt.Sprintf("decode(%x) = %q, %d, want %q, %d%s", enc, text, inst.Len, dec.text, dec.nenc, suffix))
+		}
+	})
+
+	if *mismatch {
+		totalErrors -= totalSkips
+	}
+
+	for _, b := range errors {
+		t.Log(b)
+	}
+
+	if totalErrors > 0 {
+		t.Fail()
+	}
+	t.Logf("%d test cases, %d expected mismatches, %d failures; %.0f cases/second", totalTests, totalSkips, totalErrors, float64(totalTests)/time.Since(start).Seconds())
+
+	if err := <-errc; err != nil {
+		t.Fatal("external disassembler: %v", err)
+	}
+
+}
+
+const start = 0x8000 // start address of text
+
+// writeInst writes the generated byte sequences to a new file
+// starting at offset start. That file is intended to be the input to
+// the external disassembler.
+func writeInst(generate func(func([]byte))) (file string, f *os.File, size int, err error) {
+	f, err = ioutil.TempFile("", "ppc64asm")
+	if err != nil {
+		return
+	}
+
+	file = f.Name()
+
+	f.Seek(start, 0)
+	w := bufio.NewWriter(f)
+	defer w.Flush()
+	size = 0
+	generate(func(x []byte) {
+		if len(x) > 4 {
+			x = x[:4]
+		}
+		if debug {
+			fmt.Printf("%#x: %x%x\n", start+size, x, zeros[len(x):])
+		}
+		w.Write(x)
+		w.Write(zeros[len(x):])
+		size += len(zeros)
+	})
+	return file, f, size, nil
+}
+
+var zeros = []byte{0, 0, 0, 0}
+
+// pad pads the code sequence with pops.
+func pad(enc []byte) []byte {
+	if len(enc) < 4 {
+		enc = append(enc[:len(enc):len(enc)], zeros[:4-len(enc)]...)
+	}
+	return enc
+}
+
+// disasm returns the decoded instruction and text
+// for the given source bytes, using the given syntax and mode.
+func disasm(syntax string, src []byte) (inst Inst, text string) {
+	// If printTests is set, we record the coverage value
+	// before and after, and we write out the inputs for which
+	// coverage went up, in the format expected in testdata/decode.text.
+	// This produces a fairly small set of test cases that exercise nearly
+	// all the code.
+	var cover float64
+	if *printTests {
+		cover -= coverage()
+	}
+
+	inst, err := Decode(src, binary.BigEndian)
+	if err != nil {
+		text = "error: " + err.Error()
+	} else {
+		text = inst.String()
+		switch syntax {
+		//case "arm":
+		//	text = ARMSyntax(inst)
+		case "gnu":
+			text = GNUSyntax(inst)
+		//case "plan9":
+		//	text = GoSyntax(inst, 0, nil)
+		default:
+			text = "error: unknown syntax " + syntax
+		}
+	}
+
+	if *printTests {
+		cover += coverage()
+		if cover > 0 {
+			max := len(src)
+			if max > 4 && inst.Len <= 4 {
+				max = 4
+			}
+			fmt.Printf("%x|%x\t%s\t%s\n", src[:inst.Len], src[inst.Len:max], syntax, text)
+		}
+	}
+
+	return
+}
+
+// coverage returns a floating point number denoting the
+// test coverage until now. The number increases when new code paths are exercised,
+// both in the Go program and in the decoder byte code.
+func coverage() float64 {
+	var f float64
+	f += testing.Coverage()
+	f += decodeCoverage()
+	return f
+}
+
+func decodeCoverage() float64 {
+	n := 0
+	for _, t := range decoderCover {
+		if t {
+			n++
+		}
+	}
+	return float64(1+n) / float64(1+len(decoderCover))
+}
+
+// Helpers for writing disassembler output parsers.
+
+// hasPrefix reports whether any of the space-separated words in the text s
+// begins with any of the given prefixes.
+func hasPrefix(s string, prefixes ...string) bool {
+	for _, prefix := range prefixes {
+		for s := s; s != ""; {
+			if strings.HasPrefix(s, prefix) {
+				return true
+			}
+			i := strings.Index(s, " ")
+			if i < 0 {
+				break
+			}
+			s = s[i+1:]
+		}
+	}
+	return false
+}
+
+// contains reports whether the text s contains any of the given substrings.
+func contains(s string, substrings ...string) bool {
+	for _, sub := range substrings {
+		if strings.Contains(s, sub) {
+			return true
+		}
+	}
+	return false
+}
+
+// isHex reports whether b is a hexadecimal character (0-9A-Fa-f).
+func isHex(b byte) bool { return b == '0' || unhex[b] > 0 }
+
+// parseHex parses the hexadecimal byte dump in hex,
+// appending the parsed bytes to raw and returning the updated slice.
+// The returned bool signals whether any invalid hex was found.
+// Spaces and tabs between bytes are okay but any other non-hex is not.
+func parseHex(hex []byte, raw []byte) ([]byte, bool) {
+	hex = trimSpace(hex)
+	for j := 0; j < len(hex); {
+		for hex[j] == ' ' || hex[j] == '\t' {
+			j++
+		}
+		if j >= len(hex) {
+			break
+		}
+		if j+2 > len(hex) || !isHex(hex[j]) || !isHex(hex[j+1]) {
+			return nil, false
+		}
+		raw = append(raw, unhex[hex[j]]<<4|unhex[hex[j+1]])
+		j += 2
+	}
+	return raw, true
+}
+
+var unhex = [256]byte{
+	'0': 0,
+	'1': 1,
+	'2': 2,
+	'3': 3,
+	'4': 4,
+	'5': 5,
+	'6': 6,
+	'7': 7,
+	'8': 8,
+	'9': 9,
+	'A': 10,
+	'B': 11,
+	'C': 12,
+	'D': 13,
+	'E': 14,
+	'F': 15,
+	'a': 10,
+	'b': 11,
+	'c': 12,
+	'd': 13,
+	'e': 14,
+	'f': 15,
+}
+
+// index is like bytes.Index(s, []byte(t)) but avoids the allocation.
+func index(s []byte, t string) int {
+	i := 0
+	for {
+		j := bytes.IndexByte(s[i:], t[0])
+		if j < 0 {
+			return -1
+		}
+		i = i + j
+		if i+len(t) > len(s) {
+			return -1
+		}
+		for k := 1; k < len(t); k++ {
+			if s[i+k] != t[k] {
+				goto nomatch
+			}
+		}
+		return i
+	nomatch:
+		i++
+	}
+}
+
+// fixSpace rewrites runs of spaces, tabs, and newline characters into single spaces in s.
+// If s must be rewritten, it is rewritten in place.
+func fixSpace(s []byte) []byte {
+	s = trimSpace(s)
+	for i := 0; i < len(s); i++ {
+		if s[i] == '\t' || s[i] == '\n' || i > 0 && s[i] == ' ' && s[i-1] == ' ' {
+			goto Fix
+		}
+	}
+	return s
+
+Fix:
+	b := s
+	w := 0
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if c == '\t' || c == '\n' {
+			c = ' '
+		}
+		if c == ' ' && w > 0 && b[w-1] == ' ' {
+			continue
+		}
+		b[w] = c
+		w++
+	}
+	if w > 0 && b[w-1] == ' ' {
+		w--
+	}
+	return b[:w]
+}
+
+// trimSpace trims leading and trailing space from s, returning a subslice of s.
+func trimSpace(s []byte) []byte {
+	j := len(s)
+	for j > 0 && (s[j-1] == ' ' || s[j-1] == '\t' || s[j-1] == '\n') {
+		j--
+	}
+	i := 0
+	for i < j && (s[i] == ' ' || s[i] == '\t') {
+		i++
+	}
+	return s[i:j]
+}
+
+// pcrel matches instructions using relative addressing mode.
+var (
+	pcrel = regexp.MustCompile(`^((?:.* )?(?:b|bc)[^ac ]* (?:(?:[0-9]{1,2},)|(?:[0-7]\*)|\+|lt|gt|eq|so|cr[0-7]|,)*)0x([0-9a-f]+)$`)
+)
+
+// Generators.
+//
+// The test cases are described as functions that invoke a callback repeatedly,
+// with a new input sequence each time. These helpers make writing those
+// a little easier.
+
+// randomCases generates random instructions.
+func randomCases(t *testing.T) func(func([]byte)) {
+	return func(try func([]byte)) {
+		// All the strides are relatively prime to 2 and therefore to 2²⁸,
+		// so we will not repeat any instructions until we have tried all 2²⁸.
+		// Using a stride other than 1 is meant to visit the instructions in a
+		// pseudorandom order, which gives better variety in the set of
+		// test cases chosen by -printtests.
+		stride := uint32(10007)
+		n := 1 << 28 / 7
+		if testing.Short() {
+			stride = 100003
+			n = 1 << 28 / 1001
+		} else if *longTest {
+			stride = 2000033
+			n = 1 << 29
+		}
+		x := uint32(0)
+		for i := 0; i < n; i++ {
+			enc := (x%15)<<28 | x&(1<<28-1)
+			try([]byte{byte(enc), byte(enc >> 8), byte(enc >> 16), byte(enc >> 24)})
+			x += stride
+		}
+	}
+}
+
+// hexCases generates the cases written in hexadecimal in the encoded string.
+// Spaces in 'encoded' separate entire test cases, not individual bytes.
+func hexCases(t *testing.T, encoded string) func(func([]byte)) {
+	return func(try func([]byte)) {
+		for _, x := range strings.Fields(encoded) {
+			src, err := hex.DecodeString(x)
+			if err != nil {
+				t.Errorf("parsing %q: %v", x, err)
+			}
+			try(src)
+		}
+	}
+}
+
+// testdataCases generates the test cases recorded in testdata/decode.txt.
+// It only uses the inputs; it ignores the answers recorded in that file.
+func testdataCases(t *testing.T) func(func([]byte)) {
+	var codes [][]byte
+	data, err := ioutil.ReadFile("testdata/decode.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, line := range strings.Split(string(data), "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		f := strings.Fields(line)[0]
+		i := strings.Index(f, "|")
+		if i < 0 {
+			t.Errorf("parsing %q: missing | separator", f)
+			continue
+		}
+		if i%2 != 0 {
+			t.Errorf("parsing %q: misaligned | separator", f)
+		}
+		code, err := hex.DecodeString(f[:i] + f[i+1:])
+		if err != nil {
+			t.Errorf("parsing %q: %v", f, err)
+			continue
+		}
+		codes = append(codes, code)
+	}
+
+	return func(try func([]byte)) {
+		for _, code := range codes {
+			try(code)
+		}
+	}
+}
+
+func caller(skip int) string {
+	pc, _, _, _ := runtime.Caller(skip)
+	f := runtime.FuncForPC(pc)
+	name := "?"
+	if f != nil {
+		name = f.Name()
+		if i := strings.LastIndex(name, "."); i >= 0 {
+			name = name[i+1:]
+		}
+	}
+	return name
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/field.go

+// Copyright 2014 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 ppc64asm
+
+import (
+	"fmt"
+	"strings"
+)
+
+// A BitField is a bit-field in a 32-bit word.
+// Bits are counted from 0 from the MSB to 31 as the LSB.
+type BitField struct {
+	Offs uint8 // the offset of the left-most bit.
+	Bits uint8 // length in bits.
+}
+
+func (b BitField) String() string {
+	if b.Bits > 1 {
+		return fmt.Sprintf("[%d:%d]", b.Offs, int(b.Offs+b.Bits)-1)
+	} else if b.Bits == 1 {
+		return fmt.Sprintf("[%d]", b.Offs)
+	} else {
+		return fmt.Sprintf("[%d, len=0]", b.Offs)
+	}
+}
+
+// Parse extracts the bitfield b from i, and return it as an unsigned integer.
+// Parse will panic if b is invalid.
+func (b BitField) Parse(i uint32) uint32 {
+	if b.Bits > 32 || b.Bits == 0 || b.Offs > 31 || b.Offs+b.Bits > 32 {
+		panic(fmt.Sprintf("invalid bitfiled %v", b))
+	}
+	return (i >> (32 - b.Offs - b.Bits)) & ((1 << b.Bits) - 1)
+}
+
+// ParseSigned extracts the bitfield b from i, and return it as a signed integer.
+// ParseSigned will panic if b is invalid.
+func (b BitField) ParseSigned(i uint32) int32 {
+	u := int32(b.Parse(i))
+	return u << (32 - b.Bits) >> (32 - b.Bits)
+}
+
+// BitFields is a series of BitFields representing a single number.
+type BitFields []BitField
+
+func (bs BitFields) String() string {
+	ss := make([]string, len(bs))
+	for i, bf := range bs {
+		ss[i] = bf.String()
+	}
+	return fmt.Sprintf("<%s>", strings.Join(ss, "|"))
+}
+
+func (bs *BitFields) Append(b BitField) {
+	*bs = append(*bs, b)
+}
+
+// parse extracts the bitfields from i, concatenate them and return the result
+// as an unsigned integer and the total length of all the bitfields.
+// parse will panic if any bitfield in b is invalid, but it doesn't check if
+// the sequence of bitfields is reasonable.
+func (bs BitFields) parse(i uint32) (u uint32, Bits uint8) {
+	for _, b := range bs {
+		u = (u << b.Bits) | b.Parse(i)
+		Bits += b.Bits
+	}
+	return u, Bits
+}
+
+// Parse extracts the bitfields from i, concatenate them and return the result
+// as an unsigned integer. Parse will panic if any bitfield in b is invalid.
+func (bs BitFields) Parse(i uint32) uint32 {
+	u, _ := bs.parse(i)
+	return u
+}
+
+// Parse extracts the bitfields from i, concatenate them and return the result
+// as a signed integer. Parse will panic if any bitfield in b is invalid.
+func (bs BitFields) ParseSigned(i uint32) int32 {
+	u, l := bs.parse(i)
+	return int32(u) << (32 - l) >> (32 - l)
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/field_test.go

+// Copyright 2014 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 ppc64asm
+
+import (
+	"testing"
+)
+
+func panicOrNot(f func()) (panicked bool) {
+	defer func() {
+		if err := recover(); err != nil {
+			panicked = true
+		}
+	}()
+	f()
+	return false
+}
+
+func TestBitField(t *testing.T) {
+	var tests = []struct {
+		b    BitField
+		i    uint32 // input
+		u    uint32 // unsigned output
+		s    int32  // signed output
+		fail bool   // if the check should panic
+	}{
+		{BitField{0, 0}, 0, 0, 0, true},
+		{BitField{31, 2}, 0, 0, 0, true},
+		{BitField{31, 1}, 1, 1, -1, false},
+		{BitField{29, 2}, 0 << 1, 0, 0, false},
+		{BitField{29, 2}, 1 << 1, 1, 1, false},
+		{BitField{29, 2}, 2 << 1, 2, -2, false},
+		{BitField{29, 2}, 3 << 1, 3, -1, false},
+		{BitField{0, 32}, 1<<32 - 1, 1<<32 - 1, -1, false},
+		{BitField{16, 3}, 1 << 15, 4, -4, false},
+	}
+	for i, tst := range tests {
+		var (
+			ou uint32
+			os int32
+		)
+		failed := panicOrNot(func() {
+			ou = tst.b.Parse(tst.i)
+			os = tst.b.ParseSigned(tst.i)
+		})
+		if failed != tst.fail {
+			t.Errorf("case %d: %v: fail test failed, got %v, expected %v", i, tst.b, failed, tst.fail)
+			continue
+		}
+		if ou != tst.u {
+			t.Errorf("case %d: %v.Parse(%d) returned %d, expected %d", i, tst.b, tst.i, ou, tst.u)
+			continue
+		}
+		if os != tst.s {
+			t.Errorf("case %d: %v.ParseSigned(%d) returned %d, expected %d", i, tst.b, tst.i, os, tst.s)
+		}
+	}
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/gnu.go

+// Copyright 2014 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 ppc64asm
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+)
+
+// GNUSyntax returns the GNU assembler syntax for the instruction, as defined by GNU binutils.
+// This form typically matches the syntax defined in the Power ISA Reference Manual.
+func GNUSyntax(inst Inst) string {
+	var buf bytes.Buffer
+	if inst.Op == 0 {
+		return "error: unkown instruction"
+	}
+	buf.WriteString(inst.Op.String())
+	sep := " "
+	for i, arg := range inst.Args[:] {
+		if arg == nil {
+			break
+		}
+		text := gnuArg(&inst, i, arg)
+		if text == "" {
+			continue
+		}
+		buf.WriteString(sep)
+		sep = ","
+		buf.WriteString(text)
+	}
+	return buf.String()
+}
+
+// gnuArg formats arg (which is the argIndex's arg in inst) according to GNU rules.
+// NOTE: because GNUSyntax is the only caller of this func, and it receives a copy
+//       of inst, it's ok to modify inst.Args here.
+func gnuArg(inst *Inst, argIndex int, arg Arg) string {
+	// special cases for load/store instructions
+	if _, ok := arg.(Offset); ok {
+		if argIndex+1 == len(inst.Args) || inst.Args[argIndex+1] == nil {
+			panic(fmt.Errorf("wrong table: offset not followed by register"))
+		}
+	}
+	switch arg := arg.(type) {
+	case Reg:
+		if isLoadStoreOp(inst.Op) && argIndex == 1 && arg == R0 {
+			return "0"
+		}
+		return arg.String()
+	case CondReg:
+		if arg == CR0 && strings.HasPrefix(inst.Op.String(), "cmp") {
+			return "" // don't show cr0 for cmp instructions
+		} else if arg >= CR0 {
+			return fmt.Sprintf("cr%d", int(arg-CR0))
+		}
+		bit := [4]string{"lt", "gt", "eq", "so"}[(arg-Cond0LT)%4]
+		if arg <= Cond0SO {
+			return bit
+		}
+		return fmt.Sprintf("4*cr%d+%s", int(arg-Cond0LT)/4, bit)
+	case Imm:
+		return fmt.Sprintf("%d", arg)
+	case SpReg:
+		return fmt.Sprintf("%d", int(arg))
+	case PCRel:
+		return fmt.Sprintf(".%+#x", int(arg))
+	case Label:
+		return fmt.Sprintf("%#x", uint32(arg))
+	case Offset:
+		reg := inst.Args[argIndex+1].(Reg)
+		removeArg(inst, argIndex+1)
+		if reg == R0 {
+			return fmt.Sprintf("%d(0)", int(arg))
+		}
+		return fmt.Sprintf("%d(r%d)", int(arg), reg-R0)
+	}
+	return fmt.Sprintf("???(%v)", arg)
+}
+
+// removeArg removes the arg in inst.Args[index].
+func removeArg(inst *Inst, index int) {
+	for i := index; i < len(inst.Args); i++ {
+		if i+1 < len(inst.Args) {
+			inst.Args[i] = inst.Args[i+1]
+		} else {
+			inst.Args[i] = nil
+		}
+	}
+}
+
+// isLoadStoreOp returns true if op is a load or store instruction
+func isLoadStoreOp(op Op) bool {
+	switch op {
+	case LBZ, LBZU, LBZX, LBZUX:
+		return true
+	case LHZ, LHZU, LHZX, LHZUX:
+		return true
+	case LHA, LHAU, LHAX, LHAUX:
+		return true
+	case LWZ, LWZU, LWZX, LWZUX:
+		return true
+	case LWA, LWAX, LWAUX:
+		return true
+	case LD, LDU, LDX, LDUX:
+		return true
+	case LQ:
+		return true
+	case STB, STBU, STBX, STBUX:
+		return true
+	case STH, STHU, STHX, STHUX:
+		return true
+	case STW, STWU, STWX, STWUX:
+		return true
+	case STD, STDU, STDX, STDUX:
+		return true
+	case STQ:
+		return true
+	case LHBRX, LWBRX, STHBRX, STWBRX:
+		return true
+	}
+	return false
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/inst.go

+// Copyright 2014 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 ppc64asm
+
+import (
+	"bytes"
+	"fmt"
+)
+
+type Inst struct {
+	Op   Op     // Opcode mnemonic
+	Enc  uint32 // Raw encoding bits
+	Len  int    // Length of encoding in bytes.
+	Args Args   // Instruction arguments, in Power ISA manual order.
+}
+
+func (i Inst) String() string {
+	var buf bytes.Buffer
+	buf.WriteString(i.Op.String())
+	for j, arg := range i.Args {
+		if arg == nil {
+			break
+		}
+		if j == 0 {
+			buf.WriteString(" ")
+		} else {
+			buf.WriteString(", ")
+		}
+		buf.WriteString(arg.String())
+	}
+	return buf.String()
+}
+
+// An Op is an instruction operation.
+type Op uint16
+
+func (o Op) String() string {
+	if int(o) >= len(opstr) || opstr[o] == "" {
+		return fmt.Sprintf("Op(%d)", int(o))
+	}
+	return opstr[o]
+}
+
+// An Arg is a single instruction argument, one of these types: Reg, CondReg, SpReg, Imm, PCRel, Label, or Offset.
+type Arg interface {
+	IsArg()
+	String() string
+}
+
+// An Args holds the instruction arguments.
+// If an instruction has fewer than 4 arguments,
+// the final elements in the array are nil.
+type Args [5]Arg
+
+// A Reg is a single register. The zero value means R0, not the absence of a register.
+// It also includes special registers.
+type Reg uint16
+
+const (
+	_ Reg = iota
+	R0
+	R1
+	R2
+	R3
+	R4
+	R5
+	R6
+	R7
+	R8
+	R9
+	R10
+	R11
+	R12
+	R13
+	R14
+	R15
+	R16
+	R17
+	R18
+	R19
+	R20
+	R21
+	R22
+	R23
+	R24
+	R25
+	R26
+	R27
+	R28
+	R29
+	R30
+	R31
+	F0
+	F1
+	F2
+	F3
+	F4
+	F5
+	F6
+	F7
+	F8
+	F9
+	F10
+	F11
+	F12
+	F13
+	F14
+	F15
+	F16
+	F17
+	F18
+	F19
+	F20
+	F21
+	F22
+	F23
+	F24
+	F25
+	F26
+	F27
+	F28
+	F29
+	F30
+	F31
+	V0 // VSX extension, F0 is V0[0:63].
+	V1
+	V2
+	V3
+	V4
+	V5
+	V6
+	V7
+	V8
+	V9
+	V10
+	V11
+	V12
+	V13
+	V14
+	V15
+	V16
+	V17
+	V18
+	V19
+	V20
+	V21
+	V22
+	V23
+	V24
+	V25
+	V26
+	V27
+	V28
+	V29
+	V30
+	V31
+	V32
+	V33
+	V34
+	V35
+	V36
+	V37
+	V38
+	V39
+	V40
+	V41
+	V42
+	V43
+	V44
+	V45
+	V46
+	V47
+	V48
+	V49
+	V50
+	V51
+	V52
+	V53
+	V54
+	V55
+	V56
+	V57
+	V58
+	V59
+	V60
+	V61
+	V62
+	V63
+)
+
+func (Reg) IsArg() {}
+func (r Reg) String() string {
+	switch {
+	case R0 <= r && r <= R31:
+		return fmt.Sprintf("r%d", int(r-R0))
+	case F0 <= r && r <= F31:
+		return fmt.Sprintf("f%d", int(r-F0))
+	case V0 <= r && r <= V63:
+		return fmt.Sprintf("v%d", int(r-V0))
+	default:
+		return fmt.Sprint("Reg(%d)", int(r))
+	}
+}
+
+// CondReg is a bit or field in the conditon register.
+type CondReg int8
+
+const (
+	_ CondReg = iota
+	// Condition Regster bits
+	Cond0LT
+	Cond0GT
+	Cond0EQ
+	Cond0SO
+	Cond1LT
+	Cond1GT
+	Cond1EQ
+	Cond1SO
+	Cond2LT
+	Cond2GT
+	Cond2EQ
+	Cond2SO
+	Cond3LT
+	Cond3GT
+	Cond3EQ
+	Cond3SO
+	Cond4LT
+	Cond4GT
+	Cond4EQ
+	Cond4SO
+	Cond5LT
+	Cond5GT
+	Cond5EQ
+	Cond5SO
+	Cond6LT
+	Cond6GT
+	Cond6EQ
+	Cond6SO
+	Cond7LT
+	Cond7GT
+	Cond7EQ
+	Cond7SO
+	// Condition Register Fields
+	CR0
+	CR1
+	CR2
+	CR3
+	CR4
+	CR5
+	CR6
+	CR7
+)
+
+func (CondReg) IsArg() {}
+func (c CondReg) String() string {
+	switch {
+	default:
+		return fmt.Sprintf("CondReg(%d)", int(c))
+	case c >= CR0:
+		return fmt.Sprintf("CR%d", int(c-CR0))
+	case c >= Cond0LT && c < CR0:
+		return fmt.Sprintf("Cond%d%s", int((c-Cond0LT)/4), [4]string{"LT", "GT", "EQ", "SO"}[(c-Cond0LT)%4])
+	}
+}
+
+// SpReg is a special register, its meaning depends on Op.
+type SpReg uint16
+
+const (
+	SpRegZero SpReg = 0
+)
+
+func (SpReg) IsArg() {}
+func (s SpReg) String() string {
+	return fmt.Sprintf("SpReg(%d)", int(s))
+}
+
+// PCRel is a PC-relative offset, used only in branch instructions.
+type PCRel int32
+
+func (PCRel) IsArg() {}
+func (r PCRel) String() string {
+	return fmt.Sprintf("PC%+#x", int32(r))
+}
+
+// A Label is a code (text) address, used only in absolute branch instructions.
+type Label uint32
+
+func (Label) IsArg() {}
+func (l Label) String() string {
+	return fmt.Sprintf("%#x", uint32(l))
+}
+
+// Imm represents an immediate number.
+type Imm int32
+
+func (Imm) IsArg() {}
+func (i Imm) String() string {
+	return fmt.Sprintf("%d", int32(i))
+}
+
+// Offset represents a memory offset immediate.
+type Offset int32
+
+func (Offset) IsArg() {}
+func (o Offset) String() string {
+	return fmt.Sprintf("%+d", int32(o))
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/objdump_test.go

+// Copyright 2014 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 ppc64asm
+
+import (
+	"encoding/binary"
+	"strings"
+	"testing"
+)
+
+func TestObjdumpPowerTestdata(t *testing.T) { testObjdump(t, testdataCases(t)) }
+func TestObjdumpPowerManual(t *testing.T)   { testObjdump(t, hexCases(t, objdumpManualTests)) }
+func TestObjdumpPowerRandom(t *testing.T)   { testObjdump(t, randomCases(t)) }
+
+// objdumpManualTests holds test cases that will be run by TestObjdumpARMManual.
+// If you are debugging a few cases that turned up in a longer run, it can be useful
+// to list them here and then use -run=Manual, particularly with tracing enabled.
+// Note that these are byte sequences, so they must be reversed from the usual
+// word presentation.
+var objdumpManualTests = `
+6d746162
+4c040000
+88000017
+`
+
+// allowedMismatchObjdump reports whether the mismatch between text and dec
+// should be allowed by the test.
+func allowedMismatchObjdump(text string, size int, inst *Inst, dec ExtInst) bool {
+	if hasPrefix(dec.text, deleted...) {
+		return true
+	}
+
+	// we support more instructions than binutils
+	if strings.Contains(dec.text, ".long") {
+		return true
+	}
+
+	if hasPrefix(text, "error:") {
+		if hasPrefix(dec.text, unsupported...) {
+			return true
+		}
+	}
+
+	switch inst.Op {
+	case BC, BCA, BL, BLA, BCL, BCLA, TDI, TWI, TW, TD:
+		return true // TODO(minux): we lack the support for extended opcodes here
+	case RLWNM, RLWNM_, RLDICL, RLDICL_, RLWINM, RLWINM_, RLDCL, RLDCL_:
+		return true // TODO(minux): we lack the support for extended opcodes here
+	case DCBTST, DCBT:
+		return true // objdump uses the embedded argument order, we use the server argument order
+	case MTFSF, MTFSF_: // objdump doesn't show the last two arguments
+		return true
+	case VSPLTB, VSPLTH, VSPLTW: // objdump generates unreasonable result "vspltw v6,v19,4" for 10c49a8c, the last 4 should be 0.
+		return true
+	}
+	if hasPrefix(text, "evm", "evl", "efs") { // objdump will disassemble them wrong (e.g. evmhoumia as vsldoi)
+		return true
+	}
+
+	if len(dec.enc) >= 4 {
+		_ = binary.BigEndian.Uint32(dec.enc[:4])
+	}
+
+	return false
+}
+
+// Instructions known to libopcodes (or xed) but not to us.
+// TODO(minux): those single precision instructions are missing from ppc64.csv
+// those data cache instructions are deprecated, but must be treated as no-ops, see 4.3.2.1 pg. 774.
+var unsupported = strings.Fields(`
+fmsubs
+fmsubs.
+fnmadds
+fnmadds.
+fnmsubs
+fnmsubs.
+fmuls
+fmuls.
+fdivs
+fdivs.
+fadds
+fadds.
+fsubs
+fsubs.
+dst
+dstst
+dssall
+`)
+
+// Instructions explicitly dropped in Power ISA that were in POWER architecture.
+// See A.30 Deleted Instructions and A.31 Discontiued Opcodes
+var deleted = strings.Fields(`
+abs
+clcs
+clf
+cli
+dclst
+div
+divs
+doz
+dozi
+lscbx
+maskg
+maskir
+mfsri
+mul
+nabs
+rac
+rfi
+rfsvc
+rlmi
+rrib
+sle
+sleq
+sliq
+slliq
+sllq
+slq
+sraiq
+sraq
+sre
+srea
+sreq
+sriq
+srliq
+srlq
+srq
+maskg`)

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/objdumpext_test.go

+// Copyright 2014 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.
+
+// Copied and simplified from rsc.io/arm/armasm/objdumpext_test.go.
+
+package ppc64asm
+
+import (
+	"bytes"
+	"debug/elf"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+const objdumpPath = "/usr/local/bin/powerpc64-unknown-linux-gnu-objdump"
+
+func testObjdump(t *testing.T, generate func(func([]byte))) {
+	if testing.Short() {
+		t.Skip("skipping objdump test in short mode")
+	}
+	if _, err := os.Stat(objdumpPath); err != nil {
+		t.Skip(err)
+	}
+
+	testExtDis(t, "gnu", objdump, generate, allowedMismatchObjdump)
+}
+
+func objdump(ext *ExtDis) error {
+	// File already written with instructions; add ELF header.
+	if err := writeELF64(ext.File, ext.Size); err != nil {
+		return err
+	}
+
+	b, err := ext.Run(objdumpPath, "-d", "-z", ext.File.Name())
+	if err != nil {
+		return err
+	}
+
+	var (
+		nmatch  int
+		reading bool
+		next    uint32 = start
+		addr    uint32
+		encbuf  [4]byte
+		enc     []byte
+		text    string
+	)
+	flush := func() {
+		if addr == next {
+			if m := pcrel.FindStringSubmatch(text); m != nil {
+				targ, _ := strconv.ParseUint(m[2], 16, 64)
+				text = fmt.Sprintf("%s.%+#x", m[1], int32(uint32(targ)-addr))
+			}
+			if strings.HasPrefix(text, "stmia") {
+				text = "stm" + text[5:]
+			}
+			if strings.HasPrefix(text, "stmfd") {
+				text = "stmdb" + text[5:]
+			}
+			if strings.HasPrefix(text, "ldmfd") {
+				text = "ldm" + text[5:]
+			}
+			text = strings.Replace(text, "#0.0", "#0", -1)
+			if text == "undefined" && len(enc) == 4 {
+				text = "error: unknown instruction"
+				enc = nil
+			}
+			if len(enc) == 4 {
+				// prints as word but we want to record bytes
+				enc[0], enc[3] = enc[3], enc[0]
+				enc[1], enc[2] = enc[2], enc[1]
+			}
+			ext.Dec <- ExtInst{addr, encbuf, len(enc), text}
+			encbuf = [4]byte{}
+			enc = nil
+			next += 4
+		}
+	}
+	var textangle = []byte("<.text>:")
+	for {
+		line, err := b.ReadSlice('\n')
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return fmt.Errorf("reading objdump output: %v", err)
+		}
+		if bytes.Contains(line, textangle) {
+			reading = true
+			continue
+		}
+		if !reading {
+			continue
+		}
+		if debug {
+			os.Stdout.Write(line)
+		}
+		if enc1 := parseContinuation(line, encbuf[:len(enc)]); enc1 != nil {
+			enc = enc1
+			continue
+		}
+		flush()
+		nmatch++
+		addr, enc, text = parseLine(line, encbuf[:0])
+		if addr > next {
+			return fmt.Errorf("address out of sync expected <= %#x at %q in:\n%s", next, line, line)
+		}
+	}
+	flush()
+	if next != start+uint32(ext.Size) {
+		return fmt.Errorf("not enough results found [%d %d]", next, start+ext.Size)
+	}
+	if err := ext.Wait(); err != nil {
+		return fmt.Errorf("exec: %v", err)
+	}
+
+	return nil
+}
+
+var (
+	undefined      = []byte("<UNDEFINED>")
+	unpredictable  = []byte("<UNPREDICTABLE>")
+	illegalShifter = []byte("<illegal shifter operand>")
+)
+
+func parseLine(line []byte, encstart []byte) (addr uint32, enc []byte, text string) {
+	oline := line
+	i := index(line, ":\t")
+	if i < 0 {
+		log.Fatalf("cannot parse disassembly: %q", oline)
+	}
+	x, err := strconv.ParseUint(string(trimSpace(line[:i])), 16, 32)
+	if err != nil {
+		log.Fatalf("cannot parse disassembly: %q", oline)
+	}
+	addr = uint32(x)
+	line = line[i+2:]
+	i = bytes.IndexByte(line, '\t')
+	if i < 0 {
+		log.Fatalf("cannot parse disassembly: %q", oline)
+	}
+	enc, ok := parseHex(line[:i], encstart)
+	if !ok {
+		log.Fatalf("cannot parse disassembly: %q", oline)
+	}
+	line = trimSpace(line[i:])
+	if bytes.Contains(line, undefined) {
+		text = "undefined"
+		return
+	}
+	if bytes.Contains(line, illegalShifter) {
+		text = "undefined"
+		return
+	}
+	if false && bytes.Contains(line, unpredictable) {
+		text = "unpredictable"
+		return
+	}
+	if i := bytes.IndexByte(line, ';'); i >= 0 {
+		line = trimSpace(line[:i])
+	}
+	text = string(fixSpace(line))
+	return
+}
+
+func parseContinuation(line []byte, enc []byte) []byte {
+	i := index(line, ":\t")
+	if i < 0 {
+		return nil
+	}
+	line = line[i+1:]
+	enc, _ = parseHex(line, enc)
+	return enc
+}
+
+// writeELF64 writes an ELF64 header to the file,
+// describing a text segment that starts at start
+// and extends for size bytes.
+func writeELF64(f *os.File, size int) error {
+	f.Seek(0, 0)
+	var hdr elf.Header64
+	var prog elf.Prog64
+	var sect elf.Section64
+	var buf bytes.Buffer
+	binary.Write(&buf, binary.BigEndian, &hdr)
+	off1 := buf.Len()
+	binary.Write(&buf, binary.BigEndian, &prog)
+	off2 := buf.Len()
+	binary.Write(&buf, binary.BigEndian, &sect)
+	off3 := buf.Len()
+	buf.Reset()
+	data := byte(elf.ELFDATA2MSB)
+	hdr = elf.Header64{
+		Ident:     [16]byte{0x7F, 'E', 'L', 'F', 2, data, 1},
+		Type:      2,
+		Machine:   uint16(elf.EM_PPC64),
+		Version:   1,
+		Entry:     start,
+		Phoff:     uint64(off1),
+		Shoff:     uint64(off2),
+		Flags:     0x05000002,
+		Ehsize:    uint16(off1),
+		Phentsize: uint16(off2 - off1),
+		Phnum:     1,
+		Shentsize: uint16(off3 - off2),
+		Shnum:     3,
+		Shstrndx:  2,
+	}
+	binary.Write(&buf, binary.BigEndian, &hdr)
+	prog = elf.Prog64{
+		Type:   1,
+		Off:    start,
+		Vaddr:  start,
+		Paddr:  start,
+		Filesz: uint64(size),
+		Memsz:  uint64(size),
+		Flags:  5,
+		Align:  start,
+	}
+	binary.Write(&buf, binary.BigEndian, &prog)
+	binary.Write(&buf, binary.BigEndian, &sect) // NULL section
+	sect = elf.Section64{
+		Name:      1,
+		Type:      uint32(elf.SHT_PROGBITS),
+		Addr:      start,
+		Off:       start,
+		Size:      uint64(size),
+		Flags:     uint64(elf.SHF_ALLOC | elf.SHF_EXECINSTR),
+		Addralign: 4,
+	}
+	binary.Write(&buf, binary.BigEndian, &sect) // .text
+	sect = elf.Section64{
+		Name:      uint32(len("\x00.text\x00")),
+		Type:      uint32(elf.SHT_STRTAB),
+		Addr:      0,
+		Off:       uint64(off2 + (off3-off2)*3),
+		Size:      uint64(len("\x00.text\x00.shstrtab\x00")),
+		Addralign: 1,
+	}
+	binary.Write(&buf, binary.BigEndian, &sect)
+	buf.WriteString("\x00.text\x00.shstrtab\x00")
+	f.Write(buf.Bytes())
+	return nil
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/plan9.go

+// Copyright 2015 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 ppc64asm
+
+import (
+	"fmt"
+	"strings"
+)
+
+// GoSyntax returns the Go assembler syntax for the instruction.
+// The pc is the program counter of the first instruction, used for expanding
+// PC-relative addresses into absolute ones.
+// The symname function queries the symbol table for the program
+// being disassembled. It returns the name and base address of the symbol
+// containing the target, if any; otherwise it returns "", 0.
+func GoSyntax(inst Inst, pc uint64, symname func(uint64) (string, uint64)) string {
+	if symname == nil {
+		symname = func(uint64) (string, uint64) { return "", 0 }
+	}
+	if inst.Op == 0 {
+		return "?"
+	}
+	var args []string
+	for i, a := range inst.Args[:] {
+		if a == nil {
+			break
+		}
+		if s := plan9Arg(&inst, i, pc, a, symname); s != "" {
+			args = append(args, s)
+		}
+	}
+	var op string
+	op = plan9OpMap[inst.Op]
+	if op == "" {
+		op = strings.ToUpper(inst.Op.String())
+	}
+	// laid out the instruction
+	switch inst.Op {
+	default: // dst, sA, sB, ...
+		if len(args) == 0 {
+			return op
+		} else if len(args) == 1 {
+			return fmt.Sprintf("%s %s", op, args[0])
+		}
+		args = append(args, args[0])
+		return op + " " + strings.Join(args[1:], ", ")
+	// store instructions always have the memory operand at the end, no need to reorder
+	case STB, STBU, STBX, STBUX,
+		STH, STHU, STHX, STHUX,
+		STW, STWU, STWX, STWUX,
+		STD, STDU, STDX, STDUX,
+		STQ,
+		STHBRX, STWBRX:
+		return op + " " + strings.Join(args, ", ")
+	// branch instructions needs additional handling
+	case BCLR:
+		if int(inst.Args[0].(Imm))&20 == 20 { // unconditional
+			return "RET"
+		}
+		return op + " " + strings.Join(args, ", ")
+	case BC:
+		if int(inst.Args[0].(Imm))&0x1c == 12 { // jump on cond bit set
+			return fmt.Sprintf("B%s %s", args[1], args[2])
+		} else if int(inst.Args[0].(Imm))&0x1c == 4 && revCondMap[args[1]] != "" { // jump on cond bit not set
+			return fmt.Sprintf("B%s %s", revCondMap[args[1]], args[2])
+		}
+		return op + " " + strings.Join(args, ", ")
+	case BCCTR:
+		if int(inst.Args[0].(Imm))&20 == 20 { // unconditional
+			return "BR (CTR)"
+		}
+		return op + " " + strings.Join(args, ", ")
+	case BCCTRL:
+		if int(inst.Args[0].(Imm))&20 == 20 { // unconditional
+			return "BL (CTR)"
+		}
+		return op + " " + strings.Join(args, ", ")
+	case BCA, BCL, BCLA, BCLRL, BCTAR, BCTARL:
+		return op + " " + strings.Join(args, ", ")
+	}
+}
+
+// plan9Arg formats arg (which is the argIndex's arg in inst) according to Plan 9 rules.
+// NOTE: because Plan9Syntax is the only caller of this func, and it receives a copy
+//       of inst, it's ok to modify inst.Args here.
+func plan9Arg(inst *Inst, argIndex int, pc uint64, arg Arg, symname func(uint64) (string, uint64)) string {
+	// special cases for load/store instructions
+	if _, ok := arg.(Offset); ok {
+		if argIndex+1 == len(inst.Args) || inst.Args[argIndex+1] == nil {
+			panic(fmt.Errorf("wrong table: offset not followed by register"))
+		}
+	}
+	switch arg := arg.(type) {
+	case Reg:
+		if isLoadStoreOp(inst.Op) && argIndex == 1 && arg == R0 {
+			return "0"
+		}
+		if arg == R30 {
+			return "g"
+		}
+		return strings.ToUpper(arg.String())
+	case CondReg:
+		if arg == CR0 && strings.HasPrefix(inst.Op.String(), "cmp") {
+			return "" // don't show cr0 for cmp instructions
+		} else if arg >= CR0 {
+			return fmt.Sprintf("CR%d", int(arg-CR0))
+		}
+		bit := [4]string{"LT", "GT", "EQ", "SO"}[(arg-Cond0LT)%4]
+		if arg <= Cond0SO {
+			return bit
+		}
+		return fmt.Sprintf("4*CR%d+%s", int(arg-Cond0LT)/4, bit)
+	case Imm:
+		return fmt.Sprintf("$%d", arg)
+	case SpReg:
+		switch arg {
+		case 8:
+			return "LR"
+		case 9:
+			return "CTR"
+		}
+		return fmt.Sprintf("SPR(%d)", int(arg))
+	case PCRel:
+		addr := pc + uint64(int64(arg))
+		if s, base := symname(addr); s != "" && base == addr {
+			return fmt.Sprintf("%s(SB)", s)
+		}
+		return fmt.Sprintf("%#x", addr)
+	case Label:
+		return fmt.Sprintf("%#x", int(arg))
+	case Offset:
+		reg := inst.Args[argIndex+1].(Reg)
+		removeArg(inst, argIndex+1)
+		if reg == R0 {
+			return fmt.Sprintf("%d(0)", int(arg))
+		}
+		return fmt.Sprintf("%d(R%d)", int(arg), reg-R0)
+	}
+	return fmt.Sprintf("???(%v)", arg)
+}
+
+// revCondMap maps a conditional register bit to its inverse, if possible.
+var revCondMap = map[string]string{
+	"LT": "GE", "GT": "LE", "EQ": "NE",
+}
+
+// plan9OpMap maps an Op to its Plan 9 mnemonics, if different than its GNU mnemonics.
+var plan9OpMap = map[Op]string{
+	LBZ: "MOVBZ", STB: "MOVB",
+	LBZU: "MOVBZU", STBU: "MOVBU", // TODO(minux): indexed forms are not handled
+	LHZ: "MOVHZ", LHA: "MOVH", STH: "MOVH",
+	LHZU: "MOVHZU", STHU: "MOVHU",
+	LWZ: "MOVWZ", LWA: "MOVW", STW: "MOVW",
+	LWZU: "MOVWZU", STWU: "MOVWU",
+	LD: "MOVD", STD: "MOVD",
+	LDU: "MOVDU", STDU: "MOVDU",
+	MTSPR: "MOV", MFSPR: "MOV", // the width is ambiguous for SPRs
+	B:     "BR",
+	CMPLD: "CMPU", CMPLW: "CMPWU",
+	CMPD: "CMP", CMPW: "CMPW",
+}

src/cmd/vendor/golang.org/x/arch/ppc64/ppc64asm/testdata/decode.txt

+6d746162|	gnu	xoris r20,r11,24930
+4c040000|	gnu	mcrf cr0,cr1
+88000017|	gnu	lbz r0,23(0)
+4abaa88a|	gnu	ba 0xfebaa888
+7d8fc2a6|	gnu	mfspr r12,783
+00000000|	gnu	error: unknown instruction
+a1841e80|	gnu	lhz r12,7808(r4)
+42093d10|	gnu	bc 16,4*cr2+gt,.+0x3d10
+e38d5b90|	gnu	lq r28,23440(r13)
+84127a20|	gnu	lwzu r0,31264(r18)
+c61bb730|	gnu	lfsu f16,-18640(r27)
+0825f440|	gnu	tdi 1,r5,-3008
+a9a912c1|	gnu	lha r13,4801(r9)
+ebb24fd1|	gnu	ldu r29,20432(r18)
+b1ce0612|	gnu	sth r14,1554(r14)
+f3d74322|	gnu	xvcvdpuxws v30,v40
+945c62a2|	gnu	stwu r2,25250(r28)
+9c8156e3|	gnu	stbu r4,22243(r1)
+f91b9c7a|	gnu	stq r8,-25480(r27)
+2c1c81b4|	gnu	cmpwi r28,-32332
+f87b904d|	gnu	stdu r3,-28596(r27)
+eab3c832|	gnu	lwa r21,-14288(r19)
+4320336b|	gnu	bcla 25,lt,0x3368
+7e40092e|	gnu	stwx r18,0,r1
+7c103c2c|	gnu	lwbrx r0,r16,r7

src/cmd/vendor/vendor.json

@@ -11,6 +11,12 @@
 			"local": "golang.org/x/arch/arm/armasm",
 			"revision": "ad6a463afcf9bd5b38c81fa9ba612dae11859d40",
 			"revisionTime": "2015-08-28T15:42:14Z"
+		},
+		{
+			"canonical": "golang.org/x/arch/ppc64/ppc64asm",
+			"local": "golang.org/x/arch/ppc64/ppc64asm",
+			"revision": "4831b0a617f7a819d4bf3c877d8e827d0283542c",
+			"revisionTime": "2016-10-12T18:28:04Z"
 		}
 	]
 }