STEORB, STEORLB

Atomic Exclusive-OR on byte in memory, without return, atomically loads an 8-bit byte from memory, performs an exclusive-OR with the value held in a register on it, and stores the result back to memory.

For information about memory accesses, see Load/Store addressing modes.

This is an alias of LDEORB, LDEORAB, LDEORALB, LDEORLB. This means:

Integer
(FEAT_LSE)

313029282726252423222120191817161514131211109876543210
001110000R1Rs001000Rn11111
sizeVRAo3opcRt

No memory ordering (R == 0)

STEORB <Ws>, [<Xn|SP>]

is equivalent to

LDEORB <Ws>, WZR, [<Xn|SP>]

and is always the preferred disassembly.

Release (R == 1)

STEORLB <Ws>, [<Xn|SP>]

is equivalent to

LDEORLB <Ws>, WZR, [<Xn|SP>]

and is always the preferred disassembly.

Assembler Symbols

<Ws>

Is the 32-bit name of the general-purpose register holding the data value to be operated on with the contents of the memory location, encoded in the "Rs" field.

<Xn|SP>

Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field.

Operation

The description of LDEORB, LDEORAB, LDEORALB, LDEORLB gives the operational pseudocode for this instruction.

Operational information

If PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.


Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46

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