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Compiler-specific Features
4.9 Named register variables
The compiler enables you to access registers of an ARM architecture-based processor
using named register variables.
4.9.1 Syntax
register type var-name __asm(reg);
Where:
type
var-name
reg
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
bitfield layout is sensitive to endianness.
is the name of the named register variable.
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 4-22.
Table 4-22 Named registers available on ARM architecture-based processors
Register Character string for __asm Processors
CPSR "cpsr" or "apsr" All processors
BASEPRI "basepri" Cortex-M3, Cortex-M4
BASEPRI_MAX "basepri_max" Cortex-M3, Cortex-M4
CONTROL "control" Cortex-M0, Cortex-M1, Cortex-M3,
Cortex-M4
EAPSR "eapsr" Cortex-M0, Cortex-M1, Cortex-M3,
Cortex-M4
EPSR "epsr" Cortex-M0, Cortex-M1, Cortex-M3,
Cortex-M4
FAULTMASK "faultmask" Cortex-M3, Cortex-M4
IAPSR "iapsr" Cortex-M0, Cortex-M1, Cortex-M3,
Cortex-M4
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