ARM Coretex A9 Tutorial | Core Register Access

Stack Pointer (SP/R13)

Core Register Access

The processor uses SP as a pointer to the active stack. More...

Functions
__STATIC_INLINE __ASM void	__set_SP (uint32_t stack)
	Set Stack Pointer. More...
__STATIC_INLINE __ASM void	__set_SP_usr (uint32_t topOfProcStack)
	Set USR/SYS Stack Pointer. More...

Description

The Stack Pointer is banked per processor mode. Accessing the active stack pointer actually returns/modifies the stack pointer of the current processor execution mode.

Mode	Actual SP
User/System	SP_usr
Hypervisor	SP_hyp
Supervisor	SP_svc
Abort	SP_abt
Undefined	SP_und
Monitor	SP_mon
IRQ	SP_irq
FIQ	SP_fiq

Consider __set_SP and __set_SP_usr to access this register.

Function Documentation

__STATIC_INLINE __ASM void __set_SP

(

uint32_t

stack

)

Parameters

[in]

stack

Stack Pointer value to set

This function assigns the given value to the current stack pointer.

__STATIC_INLINE __ASM void __set_SP_usr

(

uint32_t

topOfProcStack

)

Parameters

[in]

topOfProcStack

USR/SYS Stack Pointer value to set

This function assigns the given value to the User/System Stack Pointer (SP_usr).

Example:
To set value for Stack Pointer Register:
uint32_t maskValue = 0x0001;

__set_SP(maskValue);