YAVRTOS

Tasks are kept in a linked list in memory - this function reserves an "empty" task on that list, ready to be subsequently utilised by a call to create_task().

task_t *

create_task (void(*proc)(void *), void(*cleanup)(), void *init_data, uint16_t stacklen, uint8_t pri, mutex_t *memory_mutex)

Create a task, ready to be run.

yavrtos_result_t

stop_task (task_t *t, uint8_t wait_for_mutexes)

Stop a task.

void

yield () __attribute__((naked))

Stop executing the current task and try and execute a higher-priority task or another task of the same priority.

yavrtos_result_t

lock_on (mutex_t *m, semaphore_t *timeout_semaphore, int16_t timeout)

Lock on a mutex.

yavrtos_result_t

lock_off (mutex_t *m)

Unlock a mutex.

int16_t

get_current_mbox_version (mailbox_t *mbox)

Get the current version of a mailbox.

void *

read_mbox_min_version (mailbox_t *mbox, int16_t *version, semaphore_t *timeout_semaphore, int16_t timeout)

Wait for a mailbox to reach at least a certain version, and then start reading from it.

void *

read_mbox (mailbox_t *mbox, int16_t *version)

Read a mailbox.

mailbox_t *

release_mbox_read ()

Function to call when finished reading from a mailbox.

void

initialise_mbox (mailbox_t *mbox, void *data, const int16_t version)

Initialise a mailbox - this must be called on every mailbox before it is used.

yavrtos_result_t

write_mbox (mailbox_t *mbox, void *data, uint8_t wait_for_receivers, uint8_t wait_for_empty_nullify, semaphore_t *timeout_semaphore, int16_t timeout)

Write to a mailbox.

yavrtos_result_t

write_mbox_now (mailbox_t *mbox, void *data)

Attempt to write to a mailbox.

yavrtos_result_t

wait_for_receiver (mailbox_t *mbox, semaphore_t *timeout_semaphore, int16_t timeout)

Wait for a task to be suspended while trying to read from a mailbox.

yavrtos_result_t

wait_for_min_value (semaphore_t *s, int16_t value, semaphore_t *timeout_semaphore, int16_t timeout)

Wait for a semaphore to reach at least a particular value.

yavrtos_result_t

wait_for_min_value_timeout (semaphore_t *p, int16_t value, semaphore_t *timeout_semaphore, int16_t timeout_value)

Wait for a semaphore to reach at least a particular value, but with a set value for the timeout, as opposed to an increment to the timeout semaphore value.

yavrtos_result_t

wait_for_increment_of (semaphore_t *p, uint16_t amount, semaphore_t *timeout_semaphore, int16_t timeout)

Wait for a semaphore to increment its value by a certain amount.

yavrtos_result_t

wait_for_increment_of_timeout (semaphore_t *p, uint16_t amount, semaphore_t *timeout_semaphore, int16_t timeout_value)

Wait for a semaphore to increment its value by a certain amount, but with a set value for the timeout, as opposed to an increment to the timeout semaphore value.

int16_t

get_semaphore_value (semaphore_t *s)

Get the current value of a semaphore.

void

increment_semaphore_by (semaphore_t *s, uint16_t amount)

Increment the value of a semaphore by the given amount.

void

task_switcher_start (void(*idle)(void *), void *idle_data, uint16_t idle_stacklen, uint16_t system_stacklen) __attribute__((naked))

Start the whole process running.

interrupt_store_t

disable_interrupts ()

Disable interrupts system-wide.

void

restore_interrupts (interrupt_store_t interrupts)

Restore the state of the system-wide interrupts.

void

switch_task () __attribute__((naked))

For internal use only.

Perform a task switch.

Variables

task_t *

current_task

The current task.

struct yavrtos_system_struct

yavrtos_system

For internal use only.

The system_struct used to hold the system stack and a flag indicating whether an ISR is currently being executed

Define Documentation

#define restore_cpu_context ( )

Value:

__asm__ volatile ( \
                "pop r0\n" \
                "pop r31\n pop r30\n pop r29\n pop r28\n pop r27\n pop r26\n pop r25\n pop r24\n" \
                "pop r23\n pop r22\n pop r21\n pop r20\n pop r19\n pop r18\n pop r17\n pop r16\n" \
                "pop r15\n pop r14\n pop r13\n pop r12\n pop r11\n pop r10\n pop  r9\n pop  r8\n" \
                "pop  r7\n pop  r6\n pop  r5\n pop  r4\n pop  r3\n pop  r2\n pop  r1\n out 0x3f, r0\n pop  r0\n" ::)

For internal use only.

Restore the CPU context from the stack, possibly re-enabling interrupts

#define save_cpu_context ( )

Value:

__asm__ volatile( \
                "push  r0\n in r0, 0x3f\n cli\n" \
                "push  r1\n push  r2\n push  r3\n push  r4\n push  r5\n push  r6\n push  r7\n" \
                "push  r8\n push  r9\n push r10\n push r11\n push r12\n push r13\n push r14\n push r15\n" \
                "push r16\n push r17\n push r18\n push r19\n push r20\n push r21\n push r22\n push r23\n" \
                "push r24\n push r25\n push r26\n push r27\n push r28\n push r29\n push r30\n push r31\n" \
                "push  r0\n" ::)

For internal use only.

Save the CPU context to the stack, and disable interrupts

Function Documentation

void switch_task ( )

For internal use only.

Perform a task switch.

Note that interrupts must be disabled before we enter. Note also that this function must be programmed so that it never uses the stack!

Variable Documentation

struct yavrtos_system_struct yavrtos_system

For internal use only.

The system_struct used to hold the system stack and a flag indicating whether an ISR is currently being executed

Chris O'Byrne - YAVRTOS

task.h File Reference

Data Structures

Defines

Typedefs

Functions

Variables

Define Documentation

Function Documentation

Variable Documentation