## Compiler {#compiler}

## Assembler {#assembler}

<!--{
	"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

Previously, large builds could see 100%+ build time increase from enabling PGO.
In Go 1.23, overhead should be in the single digit percentages.

## Assembler {#assembler}

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.mylasta.creator;

import org.lastaflute.di.core.assembler.AutoBindingDefFactory;
import org.lastaflute.di.core.creator.ComponentCreatorImpl;
import org.lastaflute.di.core.customizer.ComponentCustomizer;
import org.lastaflute.di.core.meta.impl.InstanceDefFactory;

	"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) {

	// For backwards compatibility, MOVW $const,Rx and MOVWZ $const,Rx assemble identically
	// and accept the same constants.
	MOVW $2147483648, R5            // 64058000
	MOVWZ $-2147483648, R5          // 3ca08000

	// TODO: These are preprocessed by the assembler into MOVD $const>>shift, R5; SLD $shift, R5.

// 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 asm implements the parser and instruction generator for the assembler.
// TODO: Split apart?
package asm

import (
	"fmt"
	"io"
	"log"
	"os"
	"strconv"
	"strings"
	"text/scanner"
	"unicode/utf8"

	"cmd/asm/internal/arch"
	"cmd/asm/internal/flags"

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This input was created by taking the instruction productions in
// the old assembler's (7a's) grammar and hand-writing complete
// instructions for each rule, to guarantee we cover the same space.

#include "../../../../../runtime/textflag.h"

TEXT	foo(SB), DUPOK|NOSPLIT, $-8

// arithmetic operations

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This input was created by taking the instruction productions in
// the old assembler's (5a's) grammar and hand-writing complete
// instructions for each rule, to guarantee we cover the same space.

#include "../../../../../runtime/textflag.h"

TEXT	foo(SB), DUPOK|NOSPLIT, $0

// ADD
//

		p.errorf("%s: expected immediate constant; found %s", pseudo, obj.Dconv(&emptyProg, addr))
		return false
	}
	return true
}

// asmText assembles a TEXT pseudo-op.
// TEXT runtime·sigtramp(SB),4,$0-0
func (p *Parser) asmText(operands [][]lex.Token) {
	if len(operands) != 2 && len(operands) != 3 {
		p.errorf("expect two or three operands for TEXT")
		return