BR

Branch to register

This instruction branches unconditionally to an address in a register, with a hint that this is not a subroutine return.

Encoding: Integer

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
1	1	0	1	0	1	1	0	0	0	0	1	1	1	1	1	0	0	0	0	0	0						0	0	0	0	0
							Z		op		op2									A	M	Rn					Rm

BR <Xn>

Decoding algorithm

constant integer n = UInt(Rn);

Operation

constant bits(64) target = X[n, 64];
// Value in BTypeNext will be used to set PSTATE.BTYPE
if InGuardedPage then
    if n == 16 || n == 17 then
        BTypeNext = '01';
    else
        BTypeNext = '11';
else
    BTypeNext = '01';

constant boolean branch_conditional = FALSE;
BranchTo(target, BranchType_INDIR, branch_conditional);

Explanations

<Xn>: Is the 64-bit name of the general-purpose register holding the address to be branched to, encoded in the "Rn" field.