ACSRRW
	ACSRRS
	ACSRRC
	ACSRRWI
	ACSRRSI
	ACSRRCI

	// 3.2.1: Environment Call and Breakpoint
	AECALL
	ASCALL
	AEBREAK
	ASBREAK

	// 3.2.2: Trap-Return Instructions
	AMRET
	ASRET
	ADRET

	// 3.2.3: Wait for Interrupt
	AWFI

	// 4.2.1: Supervisor Memory-Management Fence Instruction
	ASFENCEVMA

	//
	// RISC-V Bit-Manipulation ISA-extensions (1.0)
	//

		return &inst{0x33, 0x6, 0x0, 160, 0x5}
	case AMAXU:
		return &inst{0x33, 0x7, 0x0, 160, 0x5}
	case AMIN:
		return &inst{0x33, 0x4, 0x0, 160, 0x5}
	case AMINU:
		return &inst{0x33, 0x5, 0x0, 160, 0x5}
	case AMRET:
		return &inst{0x73, 0x0, 0x2, 770, 0x18}
	case AMUL:
		return &inst{0x33, 0x0, 0x0, 32, 0x1}
	case AMULH:
		return &inst{0x33, 0x1, 0x0, 32, 0x1}
	case AMULHSU:
		return &inst{0x33, 0x2, 0x0, 32, 0x1}