FETCHMAXU

Operation

Atomically stores the unsigned maximum of memory and source and returns the old value.

Assembler Syntax

FETCHMAXU.{B|W|L|Q}(z)/order(o) Rn(s), <ea>(e)

Privilege

Unprivileged

Required CPUID flags

FETCHMAXU

Atomically compares memory and source as unsigned selected-width integers, stores the greater value, and returns the old memory value in the source register. The encoded memory-order selector governs the complete operation.

2.75in

Encodings

FETCHMAXU.{B|W|L|Q}(z)/order(o) Rn(s), <ea>(e)

Format: Instruction format for FETCHMAXU.{B|W|L|Q}(z)/order(o) Rn(s), <ea>(e)

order — allowed: 0x0..0x4 [memory_order_reserved_reclaimed]

memory — excluded: immediate [memory_operand_required]