STADDB, STADDLB

Atomic add on byte in memory, without return

This instruction atomically loads an 8-bit byte from memory, adds the value held in a register to it, and stores the result back to memory.

STADDB does not have release semantics.
STADDLB stores to memory with release semantics, as described in Load-Acquire, Store-Release.

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

The encodings in this description are named to match the encodings of LDADDB, LDADDAB, LDADDALB, LDADDLB.
The description of LDADDB, LDADDAB, LDADDALB, LDADDLB gives the operational pseudocode, any constrained unpredictable behavior, and any operational information for this instruction.

Applies when (R == 0)

is equivalent to

and is always the preferred disassembly.

Applies when (R == 1)

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

is equivalent to

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.

The description of LDADDB, LDADDAB, LDADDALB, LDADDLB gives the operational pseudocode for this instruction.