gas/

	gas/
	* config/tc-mips.c (mips_set_options): Add ase_mcu.
	(mips_opts): Initialise ase_mcu to -1.
	(ISA_SUPPORTS_MCU_ASE): New macro.
	(MIPS_CPU_ASE_MCU): Likewise.
	(is_opcode_valid): Handle MCU.
	(macro_build, macro): Likewise.
	(validate_mips_insn, validate_micromips_insn): Likewise.
	(mips_ip): Likewise.
	(options): Add OPTION_MCU and OPTION_NO_MCU.
	(md_longopts): Add mmcu and mno-mcu.
	(md_parse_option): Handle OPTION_MCU and OPTION_NO_MCU.
	(mips_after_parse_args): Handle MCU.
	(s_mipsset): Likewise.
	(md_show_usage): Handle MCU options.

	* doc/as.texinfo: Document -mmcu and -mno-mcu options.
	* doc/c-mips.texi: Likewise, and document ".set mcu" and
	".set nomcu" directives.

	gas/testsuite/
	* gas/mips/micromips@mcu.d: New test.
	* gas/mips/mcu.d: Likewise.
	* gas/mips/mcu.s: New test source.
	* gas/mips/mips.exp: Run the new tests.

	include/opcode/
	* mips.h (OP_MASK_3BITPOS, OP_SH_3BITPOS): New macros.
	(OP_MASK_OFFSET12, OP_SH_OFFSET12): Redefine.
	(INSN_ASE_MASK): Add the MCU bit.
	(INSN_MCU): New macro.
	(M_ACLR_AB, M_ACLR_OB, M_ASET_AB, M_ASET_OB): New enum values.
	(MICROMIPSOP_MASK_3BITPOS, MICROMIPSOP_SH_3BITPOS): New macros.

	opcodes/
	* mips-dis.c (mips_arch_choices): Enable MCU for "mips32r2"
	and "mips64r2".
	(print_insn_args, print_insn_micromips): Handle MCU.
	* micromips-opc.c (MC): New macro.
	(micromips_opcodes): Add "aclr", "aset" and "iret".
	* mips-opc.c (MC): New macro.
	(mips_builtin_opcodes): Add "aclr", "aset" and "iret".