Added a linker

src/linker/WriteExecutable.go

@@ -0,0 +1,50 @@
+package linker
+
+import (
+	"encoding/binary"
+	"os"
+
+	"git.urbach.dev/cli/q/src/arm"
+	"git.urbach.dev/cli/q/src/build"
+	"git.urbach.dev/cli/q/src/core"
+	"git.urbach.dev/cli/q/src/elf"
+	"git.urbach.dev/cli/q/src/x86"
+)
+
+// WriteExecutable writes an executable file to disk.
+func WriteExecutable(b *build.Build, result *core.Environment) error {
+	executable := b.Executable()
+	file, err := os.Create(executable)
+
+	if err != nil {
+		return err
+	}
+
+	code := []byte{}
+	data := []byte{}
+
+	switch b.Arch {
+	case build.ARM:
+		code = arm.MoveRegisterNumber(code, arm.X8, 93)
+		code = arm.MoveRegisterNumber(code, arm.X0, 0)
+		code = binary.LittleEndian.AppendUint32(code, arm.Syscall())
+
+	case build.X86:
+		code = x86.MoveRegisterNumber(code, x86.R0, 60)
+		code = x86.MoveRegisterNumber(code, x86.R7, 0)
+		code = x86.Syscall(code)
+	}
+
+	switch b.OS {
+	case build.Linux:
+		elf.Write(file, b, code, data)
+	}
+
+	err = file.Close()
+
+	if err != nil {
+		return err
+	}
+
+	return os.Chmod(executable, 0755)
+}