RegisterPrefix map[string]bool
	// RegisterNumber converts R(10) into arm.REG_R10.
	RegisterNumber func(string, int16) (int16, bool)
	// Instruction is a jump.
	IsJump func(word string) bool
}

// nilRegisterNumber is the register number function for architectures
// that do not accept the R(N) notation. It always returns failure.

	p.addr = p.addr[0:0]
	p.isJump = p.arch.IsJump(word)
	for _, op := range operands {
		addr := p.address(op)
		if !p.isJump && addr.Reg < 0 { // Jumps refer to PC, a pseudo.
			p.errorf("illegal use of pseudo-register in %s", word)
		}
		p.addr = append(p.addr, addr)
	}
	if p.isJump {
		p.asmJump(op, cond, p.addr)
		return
	}

		if p.arch.Family == sys.S390X {
			// 3-operand jumps.
			target = &a[2]
			prog.From = a[0]
			if a[1].Reg != 0 {
				// Compare two registers and jump.
				prog.Reg = p.getRegister(prog, op, &a[1])
			} else {
				// Compare register with immediate and jump.
				prog.AddRestSource(a[1])
			}
			break
		}
		if p.arch.Family == sys.ARM64 {
			// Special 3-operand jumps.

	"CALL":  true,
	"CBZ":   true,
	"CBZW":  true,
	"CBNZ":  true,
	"CBNZW": true,
	"JMP":   true,
	"TBNZ":  true,
	"TBZ":   true,

	// ADR isn't really a jump, but it takes a PC or label reference,
	// which needs to patched like a jump.
	"ADR":  true,
	"ADRP": true,
}

func jumpArm64(word string) bool {
	return arm64Jump[word]
}

var arm64SpecialOperand map[string]arm64.SpecialOperand