CSDB

Consumption of Speculative Data Barrier is a memory barrier that controls speculative execution arising from data value prediction. For more information and details of the semantics, see Consumption of Speculative Data Barrier (CSDB).

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 ) .

A1

313029282726252423222120191817161514131211109876543210
!= 1111001100100000(1)(1)(1)(1)(0)(0)(0)(0)00010100
cond

A1

CSDB{<c>}{<q>}

if cond != '1110' then UNPREDICTABLE; // CSDB must be encoded with AL condition

CONSTRAINED UNPREDICTABLE behavior

If cond != '1110', then one of the following behaviors must occur:

T1

15141312111098765432101514131211109876543210
111100111010(1)(1)(1)(1)10(0)0(0)00000010100

T1

CSDB{<c>}{<q>}

if InITBlock() then UNPREDICTABLE;

CONSTRAINED UNPREDICTABLE behavior

If InITBlock(), then one of the following behaviors must occur:

For more information about the constrained unpredictable behavior, see Architectural Constraints on UNPREDICTABLE behaviors.

Assembler Symbols

<c>

See Standard assembler syntax fields.

<q>

See Standard assembler syntax fields.

Operation

if ConditionPassed() then EncodingSpecificOperations(); ConsumptionOfSpeculativeDataBarrier();