control.hpp File Reference

ARM Cortex-M interrupt masking primitives. More...

Detailed Description

ARM Cortex-M interrupt masking primitives.

Two masks, two jobs:

• BASEPRI raises the execution priority to a ceiling. Handlers above the ceiling keep running — the audio ISR is never delayed by a critical section anywhere in main or control code. ScopedControlCritical is the default critical section.
• PRIMASK stops every configurable exception, audio included. It is for death paths (assert, fault) and nothing else.

The rule (research doc §4.3 item 10): nothing above the ceiling touches state that main or the control tick protect; nothing at or below it uses PRIMASK. Cortex-M7 r1p1 (the STM32H750) does not carry the r0p1 BASEPRI erratum 837070, so a plain MSR is correct.

On targets without BASEPRI (ARMv6-M) or on the host, the BASEPRI primitives are no-ops: the workbench has no interrupts to mask, and the bridge invariants are enforced by construction there (single control context, see FDP-073).

Definition in file control.hpp.

#include <cstdint>
#include <sbl/hw/hal/interrupts/types.hpp>

Go to the source code of this file.

Classes
class	sbl::hal::interrupts::ScopedControlCritical
	RAII critical section against the control tick and everything below. More...

Namespaces
namespace	sbl
	Root namespace for all Sound Byte Libs code.
namespace	sbl::hal
	Hardware abstraction: handles and convenience layers over the drivers.
namespace	sbl::hal::interrupts
	Interrupt priorities and critical sections.

Functions
uint32_t	sbl::hal::interrupts::get_basepri ()
	Read BASEPRI (0 = no ceiling).
void	sbl::hal::interrupts::set_basepri (uint32_t encoded)
	Write BASEPRI unconditionally (used to restore a saved value).
void	sbl::hal::interrupts::raise_basepri (uint32_t encoded)
uint32_t	sbl::hal::interrupts::disable_and_save ()
	Disable all configurable exceptions and return the previous PRIMASK.
void	sbl::hal::interrupts::restore (uint32_t saved_state)
	Restore PRIMASK from disable_and_save().
uint32_t	sbl::hal::interrupts::get_state ()
	Current PRIMASK (0 = enabled, 1 = disabled).
bool	sbl::hal::interrupts::are_enabled ()
	True if configurable exceptions are enabled (PRIMASK clear).