<!--{
	"Title": "A Quick Guide to Go's Assembler",
	"Path":  "/doc/asm"
}-->

<h2 id="introduction">A Quick Guide to Go's Assembler</h2>

<p>
This document is a quick outline of the unusual form of assembly language used by the <code>gc</code> Go compiler.
The document is not comprehensive.
</p>

<p>
The assembler is based on the input style of the Plan 9 assemblers, which is documented in detail

/*
Asm, typically invoked as “go tool asm”, assembles the source file into an object
file named for the basename of the argument source file with a .o suffix. The
object file can then be combined with other objects into a package archive.

# Command Line

Usage:

	go tool asm [flags] file

The specified file must be a Go assembly file.
The same assembler is used for all target operating systems and architectures.

// license that can be found in the LICENSE file.

// This file encapsulates some of the odd characteristics of the
// s390x instruction set, to minimize its interaction
// with the core of the assembler.

package arch

import (
	"cmd/internal/obj/s390x"
)

func jumpS390x(word string) bool {
	switch word {
	case "BRC",
		"BC",
		"BCL",
		"BEQ",
		"BGE",
		"BGT",
		"BL",
		"BLE",

        Model assembled = child.clone();
        assembler.assembleModelInheritance(assembled, parent, null, problems);

        // write baseName + "-actual"
        File actual = new File(
                "target/test-classes/poms/inheritance/" + baseName + (fromRepo ? "-build" : "-repo") + "-actual.xml");
        writer.write(actual, null, assembled);

// license that can be found in the LICENSE file.

// This file encapsulates some of the odd characteristics of the
// 64-bit PowerPC (PPC64) instruction set, to minimize its interaction
// with the core of the assembler.

package arch

import (
	"cmd/internal/obj"
	"cmd/internal/obj/ppc64"
)

func jumpPPC64(word string) bool {
	switch word {

// license that can be found in the LICENSE file.

// This file encapsulates some of the odd characteristics of the
// Loong64 (LoongArch64) instruction set, to minimize its interaction
// with the core of the assembler.

package arch

import (
	"cmd/internal/obj"
	"cmd/internal/obj/loong64"
	"errors"
	"fmt"
)

func jumpLoong64(word string) bool {
	switch word {

// license that can be found in the LICENSE file.

// This file encapsulates some of the odd characteristics of the
// MIPS (MIPS64) instruction set, to minimize its interaction
// with the core of the assembler.

package arch

import (
	"cmd/internal/obj"
	"cmd/internal/obj/mips"
)

func jumpMIPS(word string) bool {
	switch word {

	"fmt"
	"internal/buildcfg"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"testing"

	"cmd/asm/internal/lex"
	"cmd/internal/obj"
)

// An end-to-end test for the assembler: Do we print what we parse?
// Output is generated by, in effect, turning on -S and comparing the
// result against a golden file.

func testEndToEnd(t *testing.T, goarch, file string) {

// 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 flags implements top-level flags and the usage message for the assembler.
package flags

import (
	"cmd/internal/obj"
	"cmd/internal/objabi"
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"strings"
)

var (

// license that can be found in the LICENSE file.

// This file encapsulates some of the odd characteristics of the RISCV64
// instruction set, to minimize its interaction with the core of the
// assembler.

package arch

import (
	"cmd/internal/obj"
	"cmd/internal/obj/riscv"
	"fmt"
)

// IsRISCV64AMO reports whether op is an AMO instruction that requires
// special handling.