modes: []cbor.DecMode{modes.Decode},
			in:    hex("a1614101"), // {"A": 1}
			into: struct {
				A int `json:"a"`
			}{},
			assertOnError: assertIdenticalError(&cbor.UnknownFieldError{Index: 0}),
		},
		{
			name:  "case-insensitive match ignored in lax mode",
			modes: []cbor.DecMode{modes.DecodeLax},
			in:    hex("a1614101"), // {"A": 1}
			into: struct {
				A int `json:"a"`
			}{},

		return RegList(1 << Rt)

	case arg_satimm4:
		return Imm((x >> 16) & (1<<4 - 1))

	case arg_satimm5:
		return Imm((x >> 16) & (1<<5 - 1))

	case arg_satimm4m1:
		return Imm((x>>16)&(1<<4-1) + 1)

	case arg_satimm5m1:
		return Imm((x>>16)&(1<<5-1) + 1)

	case arg_widthm1:
		return Imm((x>>16)&(1<<5-1) + 1)

	}
}

// decodeShift decodes the shift-by-immediate encoded in x.