SYS

System instruction

For more information, see Op0 equals 0b01, cache maintenance, TLB maintenance, and address translation instructions for the encodings of System instructions.

This instruction is used by the aliases APAS, AT, BRB, CFP, COSP, CPP, DC, DVP, GCSPOPCX, GCSPOPX, GCSPUSHM, GCSPUSHX, GCSSS1, GIC, GSB, IC, MLBI, TLBI, and TRCIT.

313029282726252423222120191817161514131211109876543210
1101010100001op1CRnCRmop2Rt
L

Encoding

SYS #<op1>, <Cn>, <Cm>, #<op2>{, <Xt>}

Decode for this encoding

let t : integer = UInt(Rt); let sys_L : bits(1) = L; let sys_op0 : bits(2) = '01'; let sys_op1 : bits(3) = op1; let sys_op2 : bits(3) = op2; let sys_crn : bits(4) = CRn; let sys_crm : bits(4) = CRm;

Assembler Symbols

<op1>

Is a 3-bit unsigned immediate, in the range 0 to 7, encoded in the "op1" field.

<Cn>

Is a name 'Cn', with 'n' in the range 0 to 15, encoded in the "CRn" field.

<Cm>

Is a name 'Cm', with 'm' in the range 0 to 15, encoded in the "CRm" field.

<op2>

Is a 3-bit unsigned immediate, in the range 0 to 7, encoded in the "op2" field.

<Xt>

Is the 64-bit name of the optional general-purpose source register, defaulting to '11111', encoded in the "Rt" field.

Alias Conditions

AliasIs preferred when
APASop1 == '110' && CRn == '0111' && CRm == '0000' && op2 == '000'
ATCRn == '0111' && CRm IN {'100x'} && SysOp(op1, '0111', CRm, op2) == Sys_AT
BRBop1 == '001' && CRn == '0111' && CRm == '0010' && SysOp('001', '0111', '0010', op2) == Sys_BRB
CFPop1 == '011' && CRn == '0111' && CRm == '0011' && op2 == '100'
COSPop1 == '011' && CRn == '0111' && CRm == '0011' && op2 == '110'
CPPop1 == '011' && CRn == '0111' && CRm == '0011' && op2 == '111'
DCCRn == '0111' && SysOp(op1, '0111', CRm, op2) == Sys_DC
DVPop1 == '011' && CRn == '0111' && CRm == '0011' && op2 == '101'
GCSPOPCXop1 == '000' && CRn == '0111' && CRm == '0111' && op2 == '101'
GCSPOPXop1 == '000' && CRn == '0111' && CRm == '0111' && op2 == '110'
GCSPUSHMop1 == '011' && CRn == '0111' && CRm == '0111' && op2 == '000'
GCSPUSHXop1 == '000' && CRn == '0111' && CRm == '0111' && op2 == '100'
GCSSS1op1 == '011' && CRn == '0111' && CRm == '0111' && op2 == '010'
GICCRn == '1100' && CRm IN {'0001', '0010'} && SysOp(op1, '1100', CRm, op2) == Sys_GIC
GSBop1 == '000' && CRn == '1100' && CRm == '0000' && SysOp('000', '1100', '0000', op2) == Sys_GSB
ICCRn == '0111' && SysOp(op1, '0111', CRm, op2) == Sys_IC
MLBIop1 == '100' && CRn == '0111' && CRm == '0000' && SysOp('100', '0111', '0000', op2) == Sys_MLBI
TLBICRn IN {'100x'} && SysOp(op1, CRn, CRm, op2) == Sys_TLBI
TRCITop1 == '011' && CRn == '0111' && CRm == '0010' && op2 == '111'

2025-09_diff_tag 2025-11-28 16:29:05

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