73 lines
1.2 KiB
Go
73 lines
1.2 KiB
Go
package operand
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import (
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"fmt"
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"github.com/mmcloughlin/avo/reg"
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)
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type Op interface {
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Asm() string
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}
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type Mem struct {
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Disp int
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Base reg.Register
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Index reg.Register
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Scale uint8
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}
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func (m Mem) Asm() string {
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a := ""
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if m.Disp != 0 {
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a += fmt.Sprintf("%d", m.Disp)
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}
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if m.Base != nil {
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a += fmt.Sprintf("(%s)", m.Base.Asm())
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}
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if m.Index != nil && m.Scale != 0 {
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a += fmt.Sprintf("(%s*%d)", m.Index.Asm(), m.Scale)
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}
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return a
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}
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type Imm uint64
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func (i Imm) Asm() string {
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return fmt.Sprintf("%#x", i)
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}
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// Rel is an offset relative to the instruction pointer.
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type Rel int32
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func (r Rel) Asm() string {
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return fmt.Sprintf(".%+d", r)
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}
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// LabelRef is a reference to a label.
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type LabelRef string
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func (l LabelRef) Asm() string {
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return string(l)
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}
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// Registers returns the list of all operands involved in the given operand.
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func Registers(op Op) []reg.Register {
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switch op := op.(type) {
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case reg.Register:
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return []reg.Register{op}
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case Mem:
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var r []reg.Register
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if op.Base != nil {
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r = append(r, op.Base)
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}
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if op.Index != nil {
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r = append(r, op.Index)
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}
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return r
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case Imm, Rel, LabelRef:
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return nil
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}
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panic("unknown operand type")
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}
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