ISB -- A64

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ISB

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	1	CRm				1	1	0	1	1	1	1	1
																									opc		Rt

Decode for this encoding

Assembler Symbols

Specifies an optional limitation on the barrier operation. Values are:

SY: Full system barrier operation, encoded as CRm = 0b1111. Can be omitted.

All other encodings of "CRm" are reserved. The corresponding instructions execute as full system barrier operations, but must not be relied upon by software.

<imm>

Is an optional 4-bit unsigned immediate, in the range 0 to 15, defaulting to 15 and encoded in the "CRm" field.

Operation

InstructionSynchronizationBarrier(); if IsFeatureImplemented(FEAT_BRBE) && BRBEBranchOnISB() then BRBEISB(); end;

2025-09_rel_asl1 2026-03-12 12:57:38

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	1	CRm				1	1	0	1	1	1	1	1
																									opc		Rt

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	1	CRm				1	1	0	1	1	1	1	1
																									opc		Rt

ISB

Encoding

Decode for this encoding

Assembler Symbols

Operation

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	1	CRm				1	1	0	1	1	1	1	1
																									opc		Rt