if p.arch.Family == sys.ARM64 {
			if x >= 64 {
				p.errorf("register shift count too large: %s", str)
			}
			count = int16((x & 63) << 10)
		} else {
			if x >= 32 {
				p.errorf("register shift count too large: %s", str)
			}
			count = int16((x & 31) << 7)
		}
	default:
		p.errorf("unexpected %s in register shift", tok.String())
	}
	if p.arch.Family == sys.ARM64 {