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tm.c File Reference

Task management. More...

Functions

void tm_switcher (void)
the task switcher. More...
size_t* tm_scheduler (size_t *old_sp)
the process scheduler. More...
void yield (void)
yield the rest of the current timeslice. More...
int tm_idle_task (void)
the idle task. More...
void tm_init (void)
init task management. More...
void tm_start (void)
start task management. More...
pid_t execi (int (*code_start)(void),priority_t priority,size_t stack_size)
execute a memory image. More...
void exit (int code)
exit task, returning code. More...
wakeup_t wait_event (wakeup_t (*wakeup)(wakeup_t),wakeup_t data)
suspend process until wakeup function is non-null. More...
wakeup_t tm_sleep_wakeup (wakeup_t data)
wakeup function for sleep. More...
void kill (pid_t pid)
kill a process. More...

Variables

process_data pd_single
single process process data.
process_data* cpid
ptr to current process data.
process_data* pd_idle
idle proces.
unsigned nb_tasks
number of tasks.

Detailed Description

Task management.

Author(s):: Markus L. Noga <noga@inrialpes.fr>

Contains the multitasking switcher and scheduler as well as library functions relating to task management.

Function Documentation

void tm_switcher (void)

the task switcher.

saves active context and passes sp to scheduler then restores new context from returned sp

size_t * tm_scheduler (size_t * old_sp)

the process scheduler.

Parameters:: old_sp - current task's current stack pointer

Returns:: new task's current stack pointer

actual context switches performed by tm_switcher (assembler wrapper)

void yield (void)

yield the rest of the current timeslice.

doesn't speed up the system clock.

int tm_idle_task (void)

the idle task.

infinite sleep instruction to conserve power.

void tm_init (void)

init task management.

called in single tasking mode before task setup.

void tm_start (void)

start task management.

called in single tasking mode after task setup

pid_t execi (int(* code_start)(void), priority_t priority, size_t stack_size)

execute a memory image.

Parameters:: code_start - start address of code to execute; priority - new task's priority; stack_size - stack size for new process

Returns:: -1: fail, else pid.

will return to caller in any case.

void exit (int code)

exit task, returning code.

Parameters:: code - The return code

FIXME: for now, scrap the code.

wakeup_t wait_event (wakeup_t(* wakeup)(wakeup_t), wakeup_t data)

suspend process until wakeup function is non-null.

Parameters:: wakeup - the wakeup function. called in task scheduler context.; data - argument passed to wakeup function by scheduler

Returns:: return value passed on from wakeup

wakeup_t tm_sleep_wakeup (wakeup_t data)

wakeup function for sleep.

Parameters:: data - time to wakeup encoded as a wakeup_t

void kill (pid_t pid)

kill a process.

Parameters:: pid - must be valid process ID, or undefined behaviour will result!