17.121 STUMAX, STUMAXL, STUMAXL

Atomic unsigned maximum on word or doubleword in memory, without return.

Syntax

STUMAX Ws, [Xn|SP] ; 32-bit, no memory ordering general registers

STUMAXL Ws, [Xn|SP] ; 32-bit, release general registers

STUMAX Xs, [Xn|SP] ; 64-bit, no memory ordering general registers

STUMAXL Xs, [Xn|SP] ; 64-bit, release general registers

Where:

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.
Xn|SP
Is the 64-bit name of the general-purpose base register or stack pointer.
Xs
Is the 64-bit name of the general-purpose register holding the data value to be operated on with the contents of the memory location.

Architectures supported

Supported in the Arm®v8.1 architecture and later.

Usage

Atomic unsigned maximum on word or doubleword in memory, without return, atomically loads a 32-bit word or 64-bit doubleword from memory, compares it against the value held in a register, and stores the larger value back to memory, treating the values as unsigned numbers.

For information about memory accesses see Load/Store addressing modes in the Arm® Architecture Reference Manual Arm®v8, for Arm®v8‑A architecture profile.

Non-ConfidentialPDF file icon PDF versionDUI0801J
Copyright © 2014–2017, 2019 Arm Limited or its affiliates. All rights reserved.