func (p *Parser) atRegisterExtension() bool {
	// ARM64 only.
	if p.arch.Family != sys.ARM64 {
		return false
	}
	// R1.xxx
	if p.peek() == '.' {
		return true
	}
	return false
}
// atRegisterExtension reports whether we are at the start of an ARM64 extended register.
// We have consumed the register or R prefix.
atRegisterExtension reports whether we are at the start of an ARM64 extended register.
We have consumed the register or R prefix.
// atRegisterExtension reports whether we are at the start of an ARM64 extended register . // We have consumed the register or R prefix .
func (p *Parser) atRegisterExtension() bool {
	if p.arch.Family != sys.ARM64 {
		return false
	}
	if p.peek() == '.' {
		return true
	}
	return false
}
func ( p * Parser ) atRegisterExtension ( ) bool { if p . arch . Family != sys . ARM64 { return false } if p . peek ( ) == '.' { return true } return false }
atRegisterExtension reports whether we are at the start of an ARM64 extended register.
atRegisterExtension reports whether we are at the start of an ARM64 extended register .
// ARM64 only. // R1.xxx