Branch target identification
This instruction is used to guard against the execution of instructions that are not the intended target of a branch.
Outside of a guarded memory region, a BTI instruction executes as a NOP. Within a guarded memory region, while PSTATE.BTYPE != 0b00, a BTI instruction compatible with the current value of PSTATE.BTYPE will not generate a Branch Target Exception and will allow execution of subsequent instructions within the memory region. For more information, see PSTATE.BTYPE.
The operand <targets> passed to a BTI instruction determines the values of PSTATE.BTYPE that the BTI instruction is compatible with.
Variants: FEAT_BTI (ARMv8.5)
| 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 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | x | x | 0 | 1 | 1 | 1 | 1 | 1 |
| CRm | op2 | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
BTI {<targets>}
if !IsFeatureImplemented(FEAT_BTI) then EndOfDecode(Decode_NOP); // Check branch target compatibility between BTI instruction and PSTATE.BTYPE SetBTypeCompatible(BTypeCompatible_BTI(op2<2:1>));
SetBTypeNext('00');