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Named register variables

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4.7.49. Named register variables

The compiler enables you to access registers of an ARM architecture‑based processor using named register variables. Named register variables are supported:

• at file scope

• at local scope, but not on a function parameter.

Syntax

register type var-name __asm(reg);

Where:

type

is the type of the named register variable.

Any type of the same size as the register being named can be used in the declaration of a named register variable. The type can be a structure, but note that bitfield layout is sensitive to endianness.

var-name

is the name of the named register variable.

reg

is a character string denoting the name of a register on an ARM architecture‑based processor.

Registers available for use with named register variables on ARM architecture‑based processors are shown in Table 4.16.