78 lines
2.5 KiB
C
78 lines
2.5 KiB
C
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/*
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 2020 Felix Kopp <sandtler@sandtler.club>
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*
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* Redistribution and use in source and binary forms, with or without modification, are permitted
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* provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of its contributors may be
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* used to endorse or promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
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* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <ardix/clock.h>
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#include <ardix/sched.h>
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#include <ardix/types.h>
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#include <stddef.h>
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extern uint32_t _sstack;
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extern uint32_t _estack;
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struct process *_current_process;
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static struct process procs[SCHED_MAXPROC + 1];
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int sched_init(void)
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{
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int i;
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_current_process = &procs[0];
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_current_process->next = _current_process;
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_current_process->sp = &_sstack;
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_current_process->stack_bottom = &_estack;
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_current_process->pid = 0;
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_current_process->state = PROC_READY;
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for (i = 1; i < SCHED_MAXPROC + 1; i++) {
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procs[i].state = PROC_DEAD;
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procs[i].pid = -1;
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}
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/* TODO: initialize SysTick */
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return 0;
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}
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void *sched_process_switch(void *curr_sp)
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{
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struct process *nextproc = _current_process;
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_current_process->sp = curr_sp;
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while (true) {
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nextproc = nextproc->next;
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if (nextproc->state == PROC_QUEUE) {
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_current_process->state = PROC_QUEUE;
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nextproc->state = PROC_READY;
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_current_process = nextproc;
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break;
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}
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}
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return _current_process->sp;
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}
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