Branch to Register, with pointer authentication. This instruction authenticates the address in the general-purpose register that is specified by <Xn>, using a modifier and the specified key, and branches to the authenticated address.
The modifier is:
Key A is used for BRAA and BRAAZ, and key B is used for BRAB and BRABZ.
If the authentication passes, the PE continues execution at the target of the branch. If the authentication fails, a Translation fault is generated.
The authenticated address is not written back to the general-purpose register.
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 | Z | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | M | Rn | Rm | ||||||||
op | A |
BRAAZ <Xn>
BRABZ <Xn>
integer n = UInt(Rn); integer m = UInt(Rm); boolean use_key_a = (M == '0'); boolean source_is_sp = ((Z == '1') && (m == 31)); if !HavePACExt() then UNDEFINED; if Z == '0' && m != 31 then UNDEFINED;
<Xn> |
Is the 64-bit name of the general-purpose register holding the address to be branched to, encoded in the "Rn" field. |
<Xm|SP> |
Is the 64-bit name of the general-purpose source register or stack pointer holding the modifier, encoded in the "Rm" field. |
bits(64) target = X[n]; bits(64) modifier = if source_is_sp then SP[] else X[m]; if use_key_a then target = AuthIA(target, modifier); else target = AuthIB(target, modifier); BranchTo(target, BranchType_INDIR);
Internal version only: isa v30.41, AdvSIMD v27.08, pseudocode r8p5_00bet2_rc5, sve v8.5-00bet10_rc5 ; Build timestamp: 2019-03-28T07:14
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