tn_arch.h File Reference

Detailed Description

Architecture-dependent routines declaration.

Definition in file tn_arch.h.

Go to the source code of this file.

Functions
void	tn_arch_int_dis (void)
	Unconditionally disable interrupts.
void	tn_arch_int_en (void)
	Unconditionally enable interrupts.
unsigned int	tn_arch_sr_save_int_dis (void)
	Disable interrupts and return previous value of status register, atomically. More...
void	tn_arch_sr_restore (unsigned int sr)
	Restore previously saved status register. More...
TN_UWord *	_tn_arch_stack_top_get (TN_UWord *stack_low_address, int stack_size)
	Should return top of the stack, which may be either: More...
unsigned int *	_tn_arch_stack_init (TN_TaskBody *task_func, TN_UWord *stack_top, void *param)
	Should initialize stack for new task and return current stack pointer. More...
int	_tn_arch_inside_isr (void)
	Should return 1 if ISR is currently running, 0 otherwise.
void	_tn_arch_context_switch (void)
	Called whenever we need to switch context to other task. More...
void	_tn_arch_context_switch_exit (void)
	Called when some task calls tn_task_exit(). More...
void	_tn_arch_system_start (void)
	Should perform first context switch (to the task pointed to by tn_next_task_to_run). More...

Function Documentation

unsigned int tn_arch_sr_save_int_dis

(

void

)

Disable interrupts and return previous value of status register, atomically.

See also

tn_arch_sr_restore()

void tn_arch_sr_restore

(

unsigned int

sr

)

Restore previously saved status register.

Parameters

sr	status register value previously from tn_arch_sr_save_int_dis()

See also

tn_arch_sr_save_int_dis()

TN_UWord* _tn_arch_stack_top_get	(	TN_UWord *	stack_low_address,
		int	stack_size
	)

Should return top of the stack, which may be either:

• (stack_low_address - 1)
• (stack_low_address + stack_size)

(depending on the architecture)

NOTE that returned top of the stack is NOT the address which may be used for storing the new data. Instead, it is the previous address.

Parameters

stack_low_address	start address of the stack array.
stack_size	size of the stack in TN_UWord-s, not in bytes.

unsigned int* _tn_arch_stack_init	(	TN_TaskBody *	task_func,
		TN_UWord *	stack_top,
		void *	param
	)

Should initialize stack for new task and return current stack pointer.

Parameters

task_func	Pointer to task body function.
stack_top	Top of the stack, returned by _tn_arch_stack_top_get().
param	User-provided parameter for task body function.

Returns

current stack pointer (top of the stack)

void _tn_arch_context_switch

(

void

)

Called whenever we need to switch context to other task.

Preconditions:

• interrupts are enabled;
• tn_curr_run_task points to currently running (preempted) task;
• tn_next_task_to_run points to new task to run.

Actions to perform:

• save context of the preempted task to its stack;
• set tn_curr_run_task to tn_next_task_to_run;
• switch context to it.

See also

tn_curr_run_task

tn_next_task_to_run

void _tn_arch_context_switch_exit

(

void

)

Called when some task calls tn_task_exit().

Preconditions:

• interrupts are disabled;
• tn_next_task_to_run is already set to other task.

Actions to perform:

• set tn_curr_run_task to tn_next_task_to_run;
• switch context to it.

See also

tn_curr_run_task

tn_next_task_to_run

void _tn_arch_system_start

(

void

)

Should perform first context switch (to the task pointed to by tn_next_task_to_run).

Preconditions:

• no interrupts are set up yet, so, it's like interrupts disabled
• tn_next_task_to_run is already set to idle task.

Actions to perform:

• set TN_STATE_FLAG__SYS_RUNNING flag in the tn_sys_state variable;
• set tn_curr_run_task to tn_next_task_to_run;
• switch context to it.

See also

TN_STATE_FLAG__SYS_RUNNING

tn_sys_state

tn_curr_run_task

tn_next_task_to_run