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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

CPU_CORTEX_M && ARM

(Includes any dependencies from if’s and menus.)

Defaults

Kconfig definition

At arch/arm/core/cortex_m/Kconfig:279

Included via Kconfig:10 → Kconfig.zephyr:29 → arch/Kconfig:15 → arch/arm/Kconfig:13 → arch/arm/core/Kconfig:166

Menu path: (top menu) → ARM Options → ARM Cortex-M options

config STACK_ALIGN_DOUBLE_WORD
    bool
    prompt "Align stacks on double-words (8 octets)" if CPU_CORTEX_M && ARM
    default "y" if CPU_CORTEX_M && ARM
    depends on CPU_CORTEX_M && 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.

(Definitions include propagated dependencies, including from if’s and menus.)