ISA_v84A_A64_xml_00bet7 (old) | htmldiff from-ISA_v84A_A64_xml_00bet7 | (new) ISA_v84A_A64_xml_00bet7_OPT |
Branch with Link 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 calls a subroutine at the authenticated address, setting register X30 to PC+4.
The modifier is:
Key A is used for BLRAA and BLRAAZ, and key B is used for BLRAB and BLRABZ.
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 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | M | Rn | Rm | ||||||||
op | A |
BLRAAZ <Xn>
BLRABZ <Xn>
integer n = UInt(Rn);
integer m =(Rn); BranchType branch_type;
integer m = UInt(Rm);
boolean pac = (A == '1');
boolean use_key_a = (M == '0');
boolean source_is_sp = ((Z == '1') && (m == 31));
if !if !pac && m != 0 thenUnallocatedEncoding();
elsif pac && !HavePACExt() then
UnallocatedEncoding();
case op of
when '00' branch_type = BranchType_JMP;
when '01' branch_type = BranchType_CALL;
when '10' branch_type = BranchType_RET;
otherwise UnallocatedEncoding();
if pac then
if Z == '0' && m != 31 then
UnallocatedEncoding();
if branch_type == BranchType_RET();
if Z == '0' && m != 31 thenthen
if n !=31 then
UnallocatedEncoding();();
n = 30;
source_is_sp = TRUE;
<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 thenif pac then
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);(target, modifier);
if branch_type ==
BranchType_CALL then X[30] = PC[] + 4;
BranchTo(target, BranchType_CALL);(target, branch_type);
Internal version only: isa v29.05, AdvSIMD v26.0, pseudocode v35.3
; Build timestamp: 2018-06-16T09:5845
Copyright © 2010-2018 ARM Limited or its affiliates. All rights reserved. This document is Non-Confidential.
ISA_v84A_A64_xml_00bet7 (old) | htmldiff from-ISA_v84A_A64_xml_00bet7 | (new) ISA_v84A_A64_xml_00bet7_OPT |