(Lsh32x32 x y) => (CMOVWHSconst (SLL <x.Type> x y) (CMPconst [256] y) [0])
(Lsh32x16 x y) => (CMOVWHSconst (SLL <x.Type> x (ZeroExt16to32 y)) (CMPconst [256] (ZeroExt16to32 y)) [0])
(Lsh32x8  x y) => (SLL x (ZeroExt8to32 y))

(Lsh16x32 x y) => (CMOVWHSconst (SLL <x.Type> x y) (CMPconst [256] y) [0])
(Lsh16x16 x y) => (CMOVWHSconst (SLL <x.Type> x (ZeroExt16to32 y)) (CMPconst [256] (ZeroExt16to32 y)) [0])

	SLL	$14, R5              // 0557a0e1
	SLL	$15, R5              // 8557a0e1
	SLL	$30, R5              // 055fa0e1
	SLL	$31, R5              // 855fa0e1
	SLL.S	$14, R5              // 0557b0e1
	SLL.S	$15, R5              // 8557b0e1
	SLL.S	$30, R5              // 055fb0e1
	SLL.S	$31, R5              // 855fb0e1
	SLL	R5, R6, R7           // 1675a0e1
	SLL.S	R5, R6, R7           // 1675b0e1
	SLL	R5, R7               // 1775a0e1

		break

	case 1: /* mov r1,r2 ==> OR r1,r0,r2 */
		a := AOR
		if p.As == AMOVW && c.ctxt.Arch.Family == sys.MIPS64 {
			// on MIPS64, most of the 32-bit instructions have unpredictable behavior,
			// but SLL is special that the result is always sign-extended to 64-bit.
			a = ASLL
		}
		o1 = OP_RRR(c.oprrr(a), p.From.Reg, REGZERO, p.To.Reg)

	case 2: /* add/sub r1,[r2],r3 */
		r := p.Reg

	case 8: // mov soreg, r
		r := int(p.From.Reg)
		if r == 0 {
			r = int(o.param)
		}
		v := c.regoff(&p.From)
		o1 = OP_12IRR(c.opirr(-p.As), uint32(v), uint32(r), uint32(p.To.Reg))

	case 9: // sll r1,[r2],r3
		if p.As != ACLO && p.As != ACLZ {
			r := int(p.Reg)
			if r == 0 {
				r = int(p.To.Reg)
			}
			o1 = OP_RRR(c.oprrr(p.As), uint32(p.From.Reg), uint32(r), uint32(p.To.Reg))

		// Rotation instructions are supported natively.
		return []*instruction{ins}
	}

	switch ins.as {
	case AROL, AROLW, AROR, ARORW:
		// ROL -> OR (SLL x y) (SRL x (NEG y))
		// ROR -> OR (SRL x y) (SLL x (NEG y))
		sllOp, srlOp := ASLL, ASRL
		if ins.as == AROLW || ins.as == ARORW {
			sllOp, srlOp = ASLLW, ASRLW
		}
		shift1, shift2 := sllOp, srlOp

		rel.Siz = 0
		rel.Type = objabi.R_CALLIND

	case 8: /* sll $c,[R],R -> mov (R<<$c),R */
		c.aclass(&p.From)

		o1 = c.oprrr(p, p.As, int(p.Scond))
		r := int(p.Reg)
		if r == 0 {
			r = int(p.To.Reg)
		}
		o1 |= (uint32(r) & 15) << 0
		o1 |= uint32((c.instoffset & 31) << 7)
		o1 |= (uint32(p.To.Reg) & 15) << 12

	case 9: /* sll R,[R],R -> mov (R<<R),R */
		o1 = c.oprrr(p, p.As, int(p.Scond))

		{name: "MSUB", argLength: 3, reg: gp31, asm: "MSUB"},       // +arg0 - (arg1 * arg2)
		{name: "MSUBW", argLength: 3, reg: gp31, asm: "MSUBW"},     // +arg0 - (arg1 * arg2), 32-bit

		// shifts
		{name: "SLL", argLength: 2, reg: gp21, asm: "LSL"},                        // arg0 << arg1, shift amount is mod 64
		{name: "SLLconst", argLength: 1, reg: gp11, asm: "LSL", aux: "Int64"},     // arg0 << auxInt, auxInt should be in the range 0 to 63.