21.68 WN and XN

The WN, and XN directives define names for registers in A64 code.

The WN directive defines a name for a specified 32-bit register.

The XN directive defines a name for a specified 64-bit register.

Syntax

name directive expr

where:

name
is the name to be assigned to the register. name cannot be the same as any of the predefined names.
directive
is WN or XN.
expr
evaluates to a register number from 0 to 30.

Usage

Use WN and XN to allocate convenient names to registers in A64 code, to help you to remember what you use each register for. Be careful to avoid conflicting uses of the same register under different names.

Examples

sqr4        WN w16  ; defines sqr4 for register w16
regname     XN 21  ; defines regname for register x21
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