This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

CONFIG_STACK_ALIGN_DOUBLE_WORD

Align stacks on double-words (8 octets)

Type: bool

Help

This is needed to conform to AAPCS, the procedure call standard for
the ARM. It wastes stack space. The option also enforces alignment
of stack upon exception entry on Cortex-M3 and Cortex-M4 (ARMv7-M).
Note that for ARMv6-M, ARMv8-M, and Cortex-M7 MCUs stack alignment
on exception entry is enabled by default and it is not configurable.

Direct dependencies

ARM

(Includes any dependencies from ifs and menus.)

Default

  • y

Kconfig definition

At arch/arm/core/aarch32/Kconfig:115

Included via Kconfig:8Kconfig.zephyr:39arch/Kconfig:12arch/arm/Kconfig:57

Menu path: (Top) → ARM Options

config STACK_ALIGN_DOUBLE_WORD
    bool "Align stacks on double-words (8 octets)"
    default y
    depends on ARM
    help
      This is needed to conform to AAPCS, the procedure call standard for
      the ARM. It wastes stack space. The option also enforces alignment
      of stack upon exception entry on Cortex-M3 and Cortex-M4 (ARMv7-M).
      Note that for ARMv6-M, ARMv8-M, and Cortex-M7 MCUs stack alignment
      on exception entry is enabled by default and it is not configurable.

(The ‘depends on’ condition includes propagated dependencies from ifs and menus.)