ICARUS Kernel Core Implementation. More...

#include "icarus/kernel.h"
#include "icarus/task.h"
#include "icarus/scheduler.h"
#include "bsp/display.h"
#include "bsp/led.h"
#include <string.h>
#include <stddef.h>

Functions
void	start_cold_task (icarus_task_t *task)

void	__enter_critical (void)
	Privileged implementation of enter_critical.

void	__exit_critical (void)
	Privileged implementation of exit_critical.

static void	__init_sem (uint8_t semaphore_idx, uint32_t semaphore_count, bool should_engage)

static void	__init_pipe (uint8_t message_pipe_idx, uint16_t max_messages, bool should_engage)

static void	os_idle_task (void)

static void	os_heartbeat_task (void)

void	__os_init (void)
	Privileged implementation of os_init.

void	__os_start (void)
	Privileged implementation of os_start.

uint32_t *	__kernel_get_stack (uint8_t task_idx)
	Privileged implementation of kernel_get_stack.

uint32_t *	__kernel_get_data (uint8_t task_idx)
	Privileged implementation of kernel_get_data.

void *	__kernel_protected_data (uint16_t num_words)
	Privileged implementation of kernel_protected_data.

const char *	__os_get_task_name (uint8_t task_idx)
	Privileged implementation of os_get_task_name.

uint8_t	__os_get_num_created_tasks (void)
	Privileged implementation of os_get_num_created_tasks.

uint8_t	__os_is_running (void)
	Privileged implementation of os_is_running.

icarus_task_state_t	__os_get_task_state (uint8_t task_idx)
	Privileged implementation of os_get_task_state.

uint32_t	__os_get_task_dispatch_count (uint8_t task_idx)
	Privileged implementation of os_get_task_dispatch_count.

uint32_t	__os_get_stack_watermark (uint8_t task_idx)
	Privileged implementation of os_get_stack_watermark.

void	__os_update_stack_watermark (uint8_t task_idx)
	Scan a task's stack from the base upward for the sentinel pattern (0xDEADC0DE) and update the watermark.

Variables
icarus_task_t *	task_list [128]
	Array of pointers to all task control blocks.

icarus_semaphore_t *	semaphore_list [64]
	Array of pointers to all semaphores.

icarus_pipe_t *	message_pipe_list [64]
	Array of pointers to all message pipes.

static icarus_task_t	task_pool [128]

static icarus_semaphore_t	semaphore_pool [64]

static icarus_pipe_t	message_pipe_pool [64]

int8_t	cleanup_task_idx [128]
	Cleanup task index queue.

uint8_t	current_task_index
	Index of currently executing task.

uint8_t	running_task_count
	Count of tasks in active states.

uint8_t	num_created_tasks
	Total number of created tasks.

volatile uint32_t	current_task_ticks_remaining
	Ticks remaining in current task's time slice.

volatile uint32_t	ticks_per_task
	Configured ticks per time slice.

uint32_t	cpu_vregisters [16]

volatile uint32_t	os_tick_count
	System tick counter.

volatile uint8_t	os_running
	Flag indicating OS is running.

volatile uint8_t	critical_stack_depth

volatile bool	scheduler_enabled
	Scheduler enable flag.

int8_t	current_cleanup_task_idx
	Current cleanup queue write index.

static uint32_t	stack_pool [128][512]

static uint32_t	data_pool [128][512]

static uint16_t	data_pool_word_offsets [128]

Detailed Description

ICARUS Kernel Core Implementation.

Version: 0.1.0

Core kernel state, data structures, and initialization.

Author: Souham Biswas

Date: 2025

Copyright: Copyright 2025-2026 Souham Biswas https://github.com/ironhide23586/icarus-os-core Licensed under the Apache License, Version 2.0

Definition in file kernel.c.

Function Documentation

◆ __enter_critical()

void __enter_critical ( void )

Privileged implementation of enter_critical.

Note: Internal function - use enter_critical() wrapper

Definition at line 114 of file kernel.c.

References critical_stack_depth, and scheduler_enabled.

Referenced by crc16_ccitt(), enter_critical(), and SVC_Handler_C().

◆ __exit_critical()

void __exit_critical ( void )

Privileged implementation of exit_critical.

Note: Internal function - use exit_critical() wrapper

Definition at line 124 of file kernel.c.

References critical_stack_depth, and scheduler_enabled.

Referenced by crc16_ccitt(), exit_critical(), and SVC_Handler_C().

◆ __init_pipe()

static void __init_pipe	(	uint8_t	message_pipe_idx,
		uint16_t	max_messages,
		bool	should_engage
	)

inlinestatic

Definition at line 144 of file kernel.c.

References icarus_pipe_t::buffer, icarus_pipe_t::count, icarus_pipe_t::dequeue_idx, icarus_pipe_t::engaged, icarus_pipe_t::enqueue_idx, ICARUS_MAX_MESSAGE_BYTES, icarus_pipe_t::max_count, message_pipe_list, os_tick_count, and icarus_pipe_t::tick_updated_at.

Referenced by __os_init().

◆ __init_sem()

static void __init_sem	(	uint8_t	semaphore_idx,
		uint32_t	semaphore_count,
		bool	should_engage
	)

inlinestatic

Definition at line 135 of file kernel.c.

References icarus_semaphore_t::count, icarus_semaphore_t::engaged, icarus_semaphore_t::max_count, os_tick_count, semaphore_list, and icarus_semaphore_t::tick_updated_at.

Referenced by __os_init().

◆ __kernel_get_data()

uint32_t * __kernel_get_data ( uint8_t task_idx )

Privileged implementation of kernel_get_data.

Note: Internal function - use kernel_get_data() wrapper

Definition at line 282 of file kernel.c.

References data_pool.

Referenced by __os_register_task(), kernel_get_data(), and SVC_Handler_C().

◆ __kernel_get_stack()

uint32_t * __kernel_get_stack ( uint8_t task_idx )

Privileged implementation of kernel_get_stack.

Note: Internal function - use kernel_get_stack() wrapper

Definition at line 269 of file kernel.c.

References stack_pool.

Referenced by __os_register_task(), kernel_get_stack(), and SVC_Handler_C().

◆ __kernel_protected_data()

void * __kernel_protected_data ( uint16_t num_words )

Privileged implementation of kernel_protected_data.

Note: Internal function - use kernel_protected_data() wrapper; Runs in SVC handler — already atomic, no critical section needed

Definition at line 295 of file kernel.c.

References current_task_index, data_pool, data_pool_word_offsets, and ICARUS_DATA_WORDS.

Referenced by kernel_protected_data(), and SVC_Handler_C().

◆ __os_get_num_created_tasks()

uint8_t __os_get_num_created_tasks ( void )

Privileged implementation of os_get_num_created_tasks.

Note: Internal function - use os_get_num_created_tasks() wrapper; Runs in SVC handler — reads num_created_tasks from DTCM in privileged mode

Definition at line 345 of file kernel.c.

References num_created_tasks.

Referenced by os_get_num_created_tasks(), and SVC_Handler_C().

◆ __os_get_stack_watermark()

uint32_t __os_get_stack_watermark ( uint8_t task_idx )

Privileged implementation of os_get_stack_watermark.

Parameters

task_idx Task index.

Returns: Minimum free stack words observed.

Definition at line 387 of file kernel.c.

References num_created_tasks, icarus_task_t::stack_watermark, and task_list.

Referenced by os_get_stack_watermark(), and SVC_Handler_C().

◆ __os_get_task_dispatch_count()

uint32_t __os_get_task_dispatch_count ( uint8_t task_idx )

Privileged implementation of os_get_task_dispatch_count.

Parameters

task_idx Task index.

Returns: Dispatch count.

Definition at line 375 of file kernel.c.

References icarus_task_t::dispatch_count, num_created_tasks, and task_list.

Referenced by os_get_task_dispatch_count(), and SVC_Handler_C().

◆ __os_get_task_name()

const char * __os_get_task_name ( uint8_t task_idx )

Privileged implementation of os_get_task_name.

Note: Internal function - use os_get_task_name() wrapper; Runs in SVC handler — reads task_list from DTCM in privileged mode; Copies name to RAM_D1 buffer to allow unprivileged access

Definition at line 315 of file kernel.c.

References ICARUS_MAX_TASK_NAME_LEN, icarus_task_t::name, num_created_tasks, and task_list.

Referenced by os_get_task_name(), and SVC_Handler_C().

◆ __os_get_task_state()

icarus_task_state_t __os_get_task_state ( uint8_t task_idx )

Privileged implementation of os_get_task_state.

Parameters

task_idx Task index.

Returns: Task state enum value.

Definition at line 363 of file kernel.c.

References num_created_tasks, task_list, icarus_task_t::task_state, and TASK_STATE_FINISHED.

Referenced by os_get_task_state(), and SVC_Handler_C().

◆ __os_init()

void __os_init ( void )

Privileged implementation of os_init.

Note: Internal function - use os_init() wrapper

Definition at line 212 of file kernel.c.

References __init_pipe(), __init_sem(), __os_register_task(), cleanup_task_idx, cpu_vregisters, current_cleanup_task_idx, current_task_index, current_task_ticks_remaining, data_pool_word_offsets, ICARUS_MAX_MESSAGE_QUEUES, ICARUS_MAX_SEMAPHORES, ICARUS_MAX_TASKS, ICARUS_TICKS_PER_TASK, message_pipe_list, message_pipe_pool, os_idle_task(), os_running, running_task_count, scheduler_enabled, semaphore_list, semaphore_pool, task_list, task_pool, and ticks_per_task.

Referenced by os_init().

◆ __os_is_running()

uint8_t __os_is_running ( void )

Privileged implementation of os_is_running.

Note: Internal function - use os_is_running() wrapper; Runs in SVC handler — reads os_running from DTCM in privileged mode

Definition at line 354 of file kernel.c.

References os_running.

Referenced by os_is_running(), and SVC_Handler_C().

◆ __os_start()

void __os_start ( void )

Privileged implementation of os_start.

Note: Internal function - use os_start() wrapper

Definition at line 253 of file kernel.c.

References current_task_index, ICARUS_MAX_TASKS, num_created_tasks, start_cold_task(), and task_list.

Referenced by os_start().

◆ __os_update_stack_watermark()

void __os_update_stack_watermark ( uint8_t task_idx )

Scan a task's stack from the base upward for the sentinel pattern (0xDEADC0DE) and update the watermark.

Parameters

task_idx Task index.

Definition at line 399 of file kernel.c.

References num_created_tasks, icarus_task_t::stack_base, icarus_task_t::stack_size, icarus_task_t::stack_watermark, and task_list.

Referenced by os_update_stack_watermark(), and SVC_Handler_C().

◆ os_heartbeat_task()

static void os_heartbeat_task ( void )

static

Definition at line 175 of file kernel.c.

References display_render_banner(), ICARUS_HEARTBEAT_OFF_TICKS, ICARUS_HEARTBEAT_ON_TICKS, LED_Blink(), LED_Off(), LED_On(), os_get_current_task_name(), os_is_running(), ROW_HEARTBEAT, and task_active_sleep().

◆ os_idle_task()

static void os_idle_task ( void )

static

Definition at line 163 of file kernel.c.

References display_init(), and os_yield().

Referenced by __os_init().

◆ start_cold_task()

void start_cold_task ( icarus_task_t * task )

extern

Referenced by __os_start().

Variable Documentation

◆ cleanup_task_idx

int8_t cleanup_task_idx[128]

Cleanup task index queue.

Definition at line 57 of file kernel.c.

Referenced by __os_exit_task(), __os_init(), and __os_kill_process().

◆ cpu_vregisters

uint32_t cpu_vregisters[16]

Definition at line 68 of file kernel.c.

Referenced by __os_init().

◆ critical_stack_depth

volatile uint8_t critical_stack_depth

Definition at line 71 of file kernel.c.

Referenced by __enter_critical(), and __exit_critical().

◆ current_cleanup_task_idx

int8_t current_cleanup_task_idx

Current cleanup queue write index.

Definition at line 73 of file kernel.c.

Referenced by __os_exit_task(), __os_init(), and __os_kill_process().

◆ current_task_index

uint8_t current_task_index

Index of currently executing task.

Definition at line 63 of file kernel.c.

Referenced by __kernel_protected_data(), __os_exit_task(), __os_get_current_task_name(), __os_init(), __os_kill_process(), __os_start(), __os_task_suicide(), and __task_active_sleep().

◆ current_task_ticks_remaining

volatile uint32_t current_task_ticks_remaining

Ticks remaining in current task's time slice.

Definition at line 66 of file kernel.c.

Referenced by __os_get_task_ticks_remaining(), __os_init(), __os_yield(), and SysTick_Handler().

◆ data_pool

uint32_t data_pool[128][512]

static

Definition at line 89 of file kernel.c.

Referenced by __kernel_get_data(), and __kernel_protected_data().

◆ data_pool_word_offsets

uint16_t data_pool_word_offsets[128]

static

Definition at line 98 of file kernel.c.

Referenced by __kernel_protected_data(), and __os_init().

◆ message_pipe_list

icarus_pipe_t* message_pipe_list[64]

Array of pointers to all message pipes.

Definition at line 52 of file kernel.c.

Referenced by __init_pipe(), __os_init(), __pipe_can_dequeue(), __pipe_can_enqueue(), __pipe_dequeue(), __pipe_enqueue(), __pipe_get_count(), __pipe_get_max_count(), __pipe_init(), __pipe_read_bytes(), and __pipe_write_bytes().

◆ message_pipe_pool

icarus_pipe_t message_pipe_pool[64]

static

Definition at line 56 of file kernel.c.

Referenced by __os_init().

◆ num_created_tasks

uint8_t num_created_tasks

Total number of created tasks.

Definition at line 65 of file kernel.c.

Referenced by __os_get_current_task_name(), __os_get_num_created_tasks(), __os_get_stack_watermark(), __os_get_task_dispatch_count(), __os_get_task_name(), __os_get_task_state(), __os_kill_process(), __os_register_task(), __os_restart_task(), __os_start(), __os_update_stack_watermark(), and os_create_task().

◆ os_running

volatile uint8_t os_running

Flag indicating OS is running.

Definition at line 70 of file kernel.c.

Referenced by __os_init(), __os_is_running(), and SysTick_Handler().

◆ os_tick_count

volatile uint32_t os_tick_count

System tick counter.

Definition at line 69 of file kernel.c.

Referenced by __init_pipe(), __init_sem(), __os_get_tick_count(), __pipe_init(), __pipe_read_bytes(), __pipe_write_bytes(), __sem_decrement(), __sem_increment(), __semaphore_init(), __task_active_sleep(), __task_busy_wait(), and SysTick_Handler().

◆ running_task_count

uint8_t running_task_count

Count of tasks in active states.

Definition at line 64 of file kernel.c.

Referenced by __os_exit_task(), __os_get_running_task_count(), __os_init(), __os_kill_process(), __os_restart_task(), and os_create_task().

◆ scheduler_enabled

volatile bool scheduler_enabled

Scheduler enable flag.

Definition at line 72 of file kernel.c.

Referenced by __enter_critical(), __exit_critical(), __os_init(), and SysTick_Handler().

◆ semaphore_list

icarus_semaphore_t* semaphore_list[64]

Array of pointers to all semaphores.

Definition at line 51 of file kernel.c.

Referenced by __init_sem(), __os_init(), __sem_can_consume(), __sem_can_feed(), __sem_decrement(), __sem_increment(), __semaphore_consume(), __semaphore_consume_timeout(), __semaphore_feed(), __semaphore_get_count(), __semaphore_get_max_count(), and __semaphore_init().

◆ semaphore_pool

icarus_semaphore_t semaphore_pool[64]

static

Definition at line 55 of file kernel.c.

Referenced by __os_init().

◆ stack_pool

uint32_t stack_pool[128][512]

static

Definition at line 79 of file kernel.c.

Referenced by __kernel_get_stack().

◆ task_list

icarus_task_t* task_list[128]

Array of pointers to all task control blocks.

Definition at line 50 of file kernel.c.

Referenced by __os_exit_task(), __os_get_current_task_name(), __os_get_stack_watermark(), __os_get_task_dispatch_count(), __os_get_task_name(), __os_get_task_state(), __os_init(), __os_kill_process(), __os_register_task(), __os_restart_task(), __os_start(), __os_task_suicide(), __os_update_stack_watermark(), and __task_active_sleep().

◆ task_pool

icarus_task_t task_pool[128]

static

Definition at line 54 of file kernel.c.

Referenced by __os_init().

◆ ticks_per_task

volatile uint32_t ticks_per_task

Configured ticks per time slice.

Definition at line 67 of file kernel.c.

Referenced by __os_init(), and __os_yield().

Functions

Variables

Detailed Description

Function Documentation

◆ __enter_critical()

◆ __exit_critical()

◆ __init_pipe()

◆ __init_sem()

◆ __kernel_get_data()

◆ __kernel_get_stack()

◆ __kernel_protected_data()

◆ __os_get_num_created_tasks()

◆ __os_get_stack_watermark()

◆ __os_get_task_dispatch_count()

◆ __os_get_task_name()

◆ __os_get_task_state()

◆ __os_init()

◆ __os_is_running()

◆ __os_start()

◆ __os_update_stack_watermark()

◆ os_heartbeat_task()

◆ os_idle_task()

◆ start_cold_task()

Variable Documentation

◆ cleanup_task_idx

◆ cpu_vregisters

◆ critical_stack_depth

◆ current_cleanup_task_idx

◆ current_task_index

◆ current_task_ticks_remaining

◆ data_pool

◆ data_pool_word_offsets

◆ message_pipe_list

◆ message_pipe_pool

◆ num_created_tasks

◆ os_running

◆ os_tick_count

◆ running_task_count

◆ scheduler_enabled

◆ semaphore_list

◆ semaphore_pool

◆ stack_pool

◆ task_list

◆ task_pool

◆ ticks_per_task