73 lines
1.6 KiB
Go
73 lines
1.6 KiB
Go
package asm
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import (
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"encoding/binary"
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"fmt"
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"git.akyoto.dev/cli/q/src/build/arch/x64"
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"git.akyoto.dev/cli/q/src/build/config"
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)
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// Assembler contains a list of instructions.
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type Assembler struct {
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Instructions []Instruction
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}
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// New creates a new assembler.
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func New() *Assembler {
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return &Assembler{
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Instructions: make([]Instruction, 0, 8),
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}
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}
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// Finalize generates the final machine code.
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func (a *Assembler) Finalize() ([]byte, []byte) {
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code := make([]byte, 0, len(a.Instructions)*8)
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data := make([]byte, 0, 16)
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pointers := []Pointer{}
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for _, x := range a.Instructions {
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switch x.Mnemonic {
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case MOVE:
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code = x64.MoveRegNum32(code, uint8(x.Data.(RegisterNumber).Register), uint32(x.Data.(RegisterNumber).Number))
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if x.Data.(RegisterNumber).IsPointer {
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pointers = append(pointers, Pointer{
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Position: Address(len(code) - 4),
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Address: Address(x.Data.(RegisterNumber).Number),
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})
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}
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case RETURN:
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code = x64.Return(code)
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case SYSCALL:
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code = x64.Syscall(code)
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default:
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panic("Unknown mnemonic: " + x.Mnemonic.String())
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}
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}
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if config.Verbose {
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for _, x := range a.Instructions {
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fmt.Println("[asm]", x.String())
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}
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}
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dataStart := config.BaseAddress + config.CodeOffset + Address(len(code))
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for _, pointer := range pointers {
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slice := code[pointer.Position : pointer.Position+4]
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address := dataStart + pointer.Address
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binary.LittleEndian.PutUint32(slice, address)
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}
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return code, data
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}
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// Merge combines the contents of this assembler with another one.
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func (a *Assembler) Merge(b *Assembler) {
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a.Instructions = append(a.Instructions, b.Instructions...)
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}
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