summaryrefslogtreecommitdiffstats
path: root/src/runtime/wincallback.go
blob: fb452222da29af6163d79fc95bf8bd5ecb58ad44 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
// 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.

// +build ignore

// Generate Windows callback assembly file.

package main

import (
	"bytes"
	"fmt"
	"os"
)

const maxCallback = 2000

func genasm386Amd64() {
	var buf bytes.Buffer

	buf.WriteString(`// Code generated by wincallback.go using 'go generate'. DO NOT EDIT.

// +build 386 amd64
// runtime·callbackasm is called by external code to
// execute Go implemented callback function. It is not
// called from the start, instead runtime·compilecallback
// always returns address into runtime·callbackasm offset
// appropriately so different callbacks start with different
// CALL instruction in runtime·callbackasm. This determines
// which Go callback function is executed later on.

TEXT runtime·callbackasm(SB),7,$0
`)
	for i := 0; i < maxCallback; i++ {
		buf.WriteString("\tCALL\truntime·callbackasm1(SB)\n")
	}

	filename := fmt.Sprintf("zcallback_windows.s")
	err := os.WriteFile(filename, buf.Bytes(), 0666)
	if err != nil {
		fmt.Fprintf(os.Stderr, "wincallback: %s\n", err)
		os.Exit(2)
	}
}

func genasmArm() {
	var buf bytes.Buffer

	buf.WriteString(`// Code generated by wincallback.go using 'go generate'. DO NOT EDIT.

// External code calls into callbackasm at an offset corresponding
// to the callback index. Callbackasm is a table of MOV and B instructions.
// The MOV instruction loads R12 with the callback index, and the
// B instruction branches to callbackasm1.
// callbackasm1 takes the callback index from R12 and
// indexes into an array that stores information about each callback.
// It then calls the Go implementation for that callback.
#include "textflag.h"

TEXT runtime·callbackasm(SB),NOSPLIT|NOFRAME,$0
`)
	for i := 0; i < maxCallback; i++ {
		buf.WriteString(fmt.Sprintf("\tMOVW\t$%d, R12\n", i))
		buf.WriteString("\tB\truntime·callbackasm1(SB)\n")
	}

	err := os.WriteFile("zcallback_windows_arm.s", buf.Bytes(), 0666)
	if err != nil {
		fmt.Fprintf(os.Stderr, "wincallback: %s\n", err)
		os.Exit(2)
	}
}

func gengo() {
	var buf bytes.Buffer

	buf.WriteString(fmt.Sprintf(`// Code generated by wincallback.go using 'go generate'. DO NOT EDIT.

package runtime

const cb_max = %d // maximum number of windows callbacks allowed
`, maxCallback))
	err := os.WriteFile("zcallback_windows.go", buf.Bytes(), 0666)
	if err != nil {
		fmt.Fprintf(os.Stderr, "wincallback: %s\n", err)
		os.Exit(2)
	}
}

func main() {
	genasm386Amd64()
	genasmArm()
	gengo()
}