SETEND -- AArch32

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SETEND -- AArch32

SETEND

Set Endianness writes a new value to PSTATE.E.

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

A1

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	1	1	0	0	0	1	0	0	0	0	(0)	(0)	(0)	1	(0)	(0)	(0)	(0)	(0)	(0)	E	(0)	0	0	0	0	(0)	(0)	(0)	(0)
												imod		M	op								A	I	F		mode

Encoding

SETEND{<q>} <endian_specifier> // (Cannot be conditional)

Decode for this encoding

let set_bigend : boolean = (E == '1');

T1

15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
1	0	1	1	0	1	1	0	0	1	0	(1)	E	(0)	(0)	(0)
										op

Encoding

SETEND{<q>} <endian_specifier> // (Not permitted in IT block)

Decode for this encoding

let set_bigend : boolean = (E == '1'); if InITBlock() then UnpredictableProcedure(); end;

For more information about the CONSTRAINED UNPREDICTABLE behavior of this instruction, see Architectural Constraints on UNPREDICTABLE behaviors.

Assembler Symbols

<q>	See Standard assembler syntax fields.

<endian_specifier>

Is the endianness to be selected, and the value to be set in PSTATE.E, encoded in E:

E	<endian_specifier>
0	LE
1	BE

Operation

EncodingSpecificOperations(); AArch32_CheckSETENDEnabled(); PSTATE.E = if set_bigend then '1' else '0';

2026-03_rel 2026-03-26 20:48:11