MRS	DBGBCR2_EL1, R22                   // b60230d5
	MRS	DBGBCR3_EL1, R8                    // a80330d5
	MRS	DBGBCR4_EL1, R2                    // a20430d5
	MRS	DBGBCR5_EL1, R4                    // a40530d5
	MRS	DBGBCR6_EL1, R2                    // a20630d5
	MRS	DBGBCR7_EL1, R6                    // a60730d5
	MRS	DBGBCR8_EL1, R1                    // a10830d5
	MRS	DBGBCR9_EL1, R16                   // b00930d5

// func getisar0() uint64
TEXT ·getisar0(SB),NOSPLIT,$0-8
	// get Instruction Set Attributes 0 into x0
	// mrs x0, ID_AA64ISAR0_EL1 = d5380600
	WORD	$0xd5380600
	MOVD	R0, ret+0(FP)
	RET

// func getisar1() uint64
TEXT ·getisar1(SB),NOSPLIT,$0-8
	// get Instruction Set Attributes 1 into x0
	// mrs x0, ID_AA64ISAR1_EL1 = d5380620
	WORD	$0xd5380620
	MOVD	R0, ret+0(FP)
	RET

// func getpfr0() uint64

	MRS	ICC_EOIR1_EL1, R5                                // ERROR "system register is not readable"
	MRS	ICC_EOIR0_EL1, R5                                // ERROR "system register is not readable"
	MRS	ICC_DIR_EL1, R5                                  // ERROR "system register is not readable"
	MRS	ICC_ASGI1R_EL1, R5                               // ERROR "system register is not readable"

	MSR $1, SPSel                              // bf4100d5
	MSR $9, DAIFSet                            // df4903d5
	MSR $6, DAIFClr                            // ff4603d5
	MRS ELR_EL1, R8                            // 284038d5
	MSR R16, ELR_EL1                           // 304018d5
	MRS DCZID_EL0, R3                          // e3003bd5
	MSUBW R1, R1, R12, R5                      // 8585011b
	MSUB R19, R16, R26, R2                     // 42c3139b

		o2 |= LSL0_64

	case 35: /* mov SPR,R -> mrs */
		o1 = c.oprrr(p, AMRS)

		// SysRegEnc function returns the system register encoding and accessFlags.
		_, v, accessFlags := SysRegEnc(p.From.Reg)
		if v == 0 {
			c.ctxt.Diag("illegal system register:\n%v", p)
		}
		if (o1 & (v &^ (3 << 19))) != 0 {
			c.ctxt.Diag("MRS register value overlap\n%v", p)
		}
		if accessFlags&SR_READ == 0 {