aboutsummaryrefslogtreecommitdiff
path: root/src/cmd/internal/unvendor/golang.org/x/arch/arm/armasm/gnu.go
blob: 1a97a5a844fdc228c3b9cd6b5e851c5faa3e029e (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
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
// 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 armasm

import (
	"bytes"
	"fmt"
	"strings"
)

var saveDot = strings.NewReplacer(
	".F16", "_dot_F16",
	".F32", "_dot_F32",
	".F64", "_dot_F64",
	".S32", "_dot_S32",
	".U32", "_dot_U32",
	".FXS", "_dot_S",
	".FXU", "_dot_U",
	".32", "_dot_32",
)

// GNUSyntax returns the GNU assembler syntax for the instruction, as defined by GNU binutils.
// This form typically matches the syntax defined in the ARM Reference Manual.
func GNUSyntax(inst Inst) string {
	var buf bytes.Buffer
	op := inst.Op.String()
	op = saveDot.Replace(op)
	op = strings.Replace(op, ".", "", -1)
	op = strings.Replace(op, "_dot_", ".", -1)
	op = strings.ToLower(op)
	buf.WriteString(op)
	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()
}

func gnuArg(inst *Inst, argIndex int, arg Arg) string {
	switch inst.Op &^ 15 {
	case LDRD_EQ, LDREXD_EQ, STRD_EQ:
		if argIndex == 1 {
			// second argument in consecutive pair not printed
			return ""
		}
	case STREXD_EQ:
		if argIndex == 2 {
			// second argument in consecutive pair not printed
			return ""
		}
	}

	switch arg := arg.(type) {
	case Imm:
		switch inst.Op &^ 15 {
		case BKPT_EQ:
			return fmt.Sprintf("%#04x", uint32(arg))
		case SVC_EQ:
			return fmt.Sprintf("%#08x", uint32(arg))
		}
		return fmt.Sprintf("#%d", int32(arg))

	case ImmAlt:
		return fmt.Sprintf("#%d, %d", arg.Val, arg.Rot)

	case Mem:
		R := gnuArg(inst, -1, arg.Base)
		X := ""
		if arg.Sign != 0 {
			X = ""
			if arg.Sign < 0 {
				X = "-"
			}
			X += gnuArg(inst, -1, arg.Index)
			if arg.Shift == ShiftLeft && arg.Count == 0 {
				// nothing
			} else if arg.Shift == RotateRightExt {
				X += ", rrx"
			} else {
				X += fmt.Sprintf(", %s #%d", strings.ToLower(arg.Shift.String()), arg.Count)
			}
		} else {
			X = fmt.Sprintf("#%d", arg.Offset)
		}

		switch arg.Mode {
		case AddrOffset:
			if X == "#0" {
				return fmt.Sprintf("[%s]", R)
			}
			return fmt.Sprintf("[%s, %s]", R, X)
		case AddrPreIndex:
			return fmt.Sprintf("[%s, %s]!", R, X)
		case AddrPostIndex:
			return fmt.Sprintf("[%s], %s", R, X)
		case AddrLDM:
			if X == "#0" {
				return R
			}
		case AddrLDM_WB:
			if X == "#0" {
				return R + "!"
			}
		}
		return fmt.Sprintf("[%s Mode(%d) %s]", R, int(arg.Mode), X)

	case PCRel:
		return fmt.Sprintf(".%+#x", int32(arg)+4)

	case Reg:
		switch inst.Op &^ 15 {
		case LDREX_EQ:
			if argIndex == 0 {
				return fmt.Sprintf("r%d", int32(arg))
			}
		}
		switch arg {
		case R10:
			return "sl"
		case R11:
			return "fp"
		case R12:
			return "ip"
		}

	case RegList:
		var buf bytes.Buffer
		fmt.Fprintf(&buf, "{")
		sep := ""
		for i := 0; i < 16; i++ {
			if arg&(1<<uint(i)) != 0 {
				fmt.Fprintf(&buf, "%s%s", sep, gnuArg(inst, -1, Reg(i)))
				sep = ", "
			}
		}
		fmt.Fprintf(&buf, "}")
		return buf.String()

	case RegShift:
		if arg.Shift == ShiftLeft && arg.Count == 0 {
			return gnuArg(inst, -1, arg.Reg)
		}
		if arg.Shift == RotateRightExt {
			return gnuArg(inst, -1, arg.Reg) + ", rrx"
		}
		return fmt.Sprintf("%s, %s #%d", gnuArg(inst, -1, arg.Reg), strings.ToLower(arg.Shift.String()), arg.Count)

	case RegShiftReg:
		return fmt.Sprintf("%s, %s %s", gnuArg(inst, -1, arg.Reg), strings.ToLower(arg.Shift.String()), gnuArg(inst, -1, arg.RegCount))

	}
	return strings.ToLower(arg.String())
}