print.go

Documentation: golang.org/x/arch/x86/x86avxgen

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package main
     6  
     7  import (
     8  	"bytes"
     9  	"go/format"
    10  	"io"
    11  	"log"
    12  	"sort"
    13  	"text/template"
    14  )
    15  
    16  var tablesTemplate = template.Must(template.New("avx_optabs").Parse(`
    17  // Code generated by x86avxgen. DO NOT EDIT.
    18  
    19  package x86
    20  
    21  // VEX instructions that come in two forms:
    22  //	VTHING xmm2/m128, xmmV, xmm1
    23  //	VTHING ymm2/m256, ymmV, ymm1
    24  //
    25  // The opcode array in the corresponding Optab entry
    26  // should contain the (VEX prefixes, opcode byte) pair
    27  // for each of the two forms.
    28  // For example, the entries for VPXOR are:
    29  //
    30  //	VPXOR xmm2/m128, xmmV, xmm1
    31  //	VEX.NDS.128.66.0F.WIG EF /r
    32  //
    33  //	VPXOR ymm2/m256, ymmV, ymm1
    34  //	VEX.NDS.256.66.0F.WIG EF /r
    35  //
    36  // Produce this optab entry:
    37  //
    38  //	{AVPXOR, yvex_xy3, Pavx, opBytes{vex128|vex66|vex0F|vexWIG, 0xEF, vex256|vex66|vex0F|vexWIG, 0xEF}}
    39  //
    40  // VEX requires at least 2 bytes inside opBytes:
    41  //	- VEX prefixes (vex-prefixed constants)
    42  //	- Opcode byte
    43  //
    44  // EVEX instructions extend VEX form variety:
    45  //	VTHING zmm2/m512, zmmV, zmm1    -- implicit K0 (merging)
    46  //	VTHING zmm2/m512, zmmV, K, zmm1 -- explicit K mask (can't use K0)
    47  //
    48  // EVEX requires at least 3 bytes inside opBytes:
    49  //	- EVEX prefixes (evex-prefixed constants); similar to VEX
    50  //	- Displacement multiplier info (scale / broadcast scale)
    51  //	- Opcode byte; similar to VEX
    52  //
    53  // Both VEX and EVEX instructions may have opdigit (opcode extension) byte
    54  // which follows the primary opcode byte.
    55  // Because it can only have value of 0-7, it is written in octal notation.
    56  //
    57  // x86.csv can be very useful for figuring out proper [E]VEX parts.
    58  
    59  {{ range .Ylists }}
    60    var {{.Name}} = []ytab{
    61      {{- range .Ytabs }}
    62        {zcase: {{.Zcase}}, zoffset: {{.Zoffset}}, args: argList{ {{.ArgList}} }},
    63      {{- end }}
    64    }
    65  {{ end }}
    66  
    67  var avxOptab = [...]Optab{
    68    {{- range .Optabs }}
    69      {as: {{.Opcode}}, ytab: {{.YtabList.Name}}, prefix: Pavx, op: opBytes{
    70        {{- range .OpLines }}
    71          {{.}},
    72        {{- end }}
    73      }},
    74    {{- end }}
    75  }
    76  `))
    77  
    78  // writeTables writes avx optabs file contents to w.
    79  func writeTables(w io.Writer, ctx *context) {
    80  	ylists := make([]*ytabList, 0, len(ctx.ytabLists))
    81  	for _, ylist := range ctx.ytabLists {
    82  		ylists = append(ylists, ylist)
    83  	}
    84  	sort.Slice(ylists, func(i, j int) bool {
    85  		return ylists[i].Name < ylists[j].Name
    86  	})
    87  	optabs := make([]*optab, 0, len(ctx.optabs))
    88  	for _, o := range ctx.optabs {
    89  		optabs = append(optabs, o)
    90  	}
    91  	sort.Slice(optabs, func(i, j int) bool {
    92  		return optabs[i].Opcode < optabs[j].Opcode
    93  	})
    94  
    95  	var buf bytes.Buffer
    96  	err := tablesTemplate.Execute(&buf, struct {
    97  		Ylists []*ytabList
    98  		Optabs []*optab
    99  	}{
   100  		Ylists: ylists,
   101  		Optabs: optabs,
   102  	})
   103  	if err != nil {
   104  		log.Fatalf("template execute error: %v", err)
   105  	}
   106  
   107  	// TODO: invoke "go fmt" or format.Gofmt? #22695.
   108  	prettyCode, err := format.Source(buf.Bytes())
   109  	if err != nil {
   110  		log.Fatalf("gofmt error: %v", err)
   111  	}
   112  
   113  	if _, err := w.Write(prettyCode); err != nil {
   114  		log.Fatalf("write output: %v", err)
   115  	}
   116  }
   117
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