231 lines
6.7 KiB
C
231 lines
6.7 KiB
C
/*
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* Copyright (c) 2006, Technical University of Munich
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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* \file AVR specific implementation of multithreading architecture
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*
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* \author Adam Dunkels <adam@sics.se>
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* \author Simon Barner <barner@in.tum.de>
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*
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* @(#)$Id: mtarch.c,v 1.1 2006/12/22 16:55:53 barner Exp $
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*/
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#include <stdio.h>
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#include "sys/mt.h"
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#include "dev/rs232.h"
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/*--------------------------------------------------------------------------*/
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void
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mtarch_init(void)
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{
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}
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/*--------------------------------------------------------------------------*/
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void
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mtarch_start(struct mtarch_thread *t,
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void (*function)(void *), void *data)
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{
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/* Initialize stack with number sequence (used for
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* measuring stack usage */
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uint8_t i;
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for(i = 0; i < MTARCH_STACKSIZE; ++i) {
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t->stack[i] = i;
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}
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/*
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* Push pointer to mt_exit and the thread onto our stack:
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* Caveats:
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* - The stack is defined as an array of bytes, but pointers are 16 bit wide
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* - Function pointers are 16-bit addresses in flash ROM, but e.g.
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* avr-objdump displays byte addresses
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* - Get the high and low byte of the addresses onto the stack in the
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* right order
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*/
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/* Initialize stack. This is done in reverse order ("pushing") the
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* pre-allocated array */
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/* mt_exit function that is to be invoked if the thread dies */
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t->stack[MTARCH_STACKSIZE - 1] = (unsigned char)((unsigned short)mt_exit) & 0xff;
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t->stack[MTARCH_STACKSIZE - 2] = (unsigned char)((unsigned short)mt_exit >> 8) & 0xff;
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/* The thread handler. Invoked when RET is called in mtarch_exec */
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t->stack[MTARCH_STACKSIZE - 3] = (unsigned char)((unsigned short)function) & 0xff;
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t->stack[MTARCH_STACKSIZE - 4] = (unsigned char)((unsigned short)function >> 8) & 0xff;
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/* Register r0-r23 in t->stack[MTARCH_STACKSIZE - 5] to
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* t->stack[MTARCH_STACKSIZE - 28].
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*
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* Per calling convention, the argument to the thread handler function
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* (i.e. the 'data' pointer) is passed via r24-r25.
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* See http://www.nongnu.org/avr-libc/user-manual/FAQ.html#faq_reg_usage) */
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t->stack[MTARCH_STACKSIZE - 29] = (unsigned char)((unsigned short)data) & 0xff;
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t->stack[MTARCH_STACKSIZE - 30] = (unsigned char)((unsigned short)data >> 8) & 0xff;
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/* Initialize stack pointer: Space for 2 2-byte-addresses and 32 registers,
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* post-decrement POP / pre-increment PUSH scheme */
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t->sp = &t->stack[MTARCH_STACKSIZE - 1 - 4 - 32];
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}
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/*--------------------------------------------------------------------------*/
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static unsigned char *sptmp;
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static struct mtarch_thread *running;
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static void
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sw(void)
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{
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/* Disable interrupts while we perform the context switch */
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cli ();
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/* Push 32 general purpuse registers */
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__asm__("push r0");
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__asm__("push r1");
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__asm__("push r2");
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__asm__("push r3");
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__asm__("push r4");
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__asm__("push r5");
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__asm__("push r6");
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__asm__("push r7");
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__asm__("push r8");
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__asm__("push r9");
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__asm__("push r10");
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__asm__("push r11");
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__asm__("push r12");
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__asm__("push r13");
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__asm__("push r14");
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__asm__("push r15");
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__asm__("push r16");
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__asm__("push r17");
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__asm__("push r18");
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__asm__("push r19");
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__asm__("push r20");
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__asm__("push r21");
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__asm__("push r22");
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__asm__("push r23");
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__asm__("push r24");
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__asm__("push r25");
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__asm__("push r26");
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__asm__("push r27");
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__asm__("push r28");
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__asm__("push r29");
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__asm__("push r30");
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__asm__("push r31");
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/* Switch stack pointer */
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sptmp = running->sp;
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running->sp = (unsigned char*)SP;
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SP = (unsigned short)sptmp;
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/* Pop 32 general purpose registers */
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__asm__("pop r31");
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__asm__("pop r30");
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__asm__("pop r29");
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__asm__("pop r28");
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__asm__("pop r27");
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__asm__("pop r26");
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__asm__("pop r25");
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__asm__("pop r24");
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__asm__("pop r23");
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__asm__("pop r22");
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__asm__("pop r21");
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__asm__("pop r20");
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__asm__("pop r19");
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__asm__("pop r18");
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__asm__("pop r17");
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__asm__("pop r16");
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__asm__("pop r15");
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__asm__("pop r14");
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__asm__("pop r13");
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__asm__("pop r12");
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__asm__("pop r11");
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__asm__("pop r10");
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__asm__("pop r9");
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__asm__("pop r8");
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__asm__("pop r7");
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__asm__("pop r6");
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__asm__("pop r5");
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__asm__("pop r4");
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__asm__("pop r3");
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__asm__("pop r2");
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__asm__("pop r1");
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__asm__("pop r0");
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/* Renable interrupts */
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sei ();
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}
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/*--------------------------------------------------------------------------*/
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void
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mtarch_exec(struct mtarch_thread *t)
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{
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running = t;
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sw();
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running = NULL;
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}
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/*--------------------------------------------------------------------------*/
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void
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mtarch_remove(void)
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{
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}
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/*--------------------------------------------------------------------------*/
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void
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mtarch_yield(void)
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{
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sw();
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}
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/*--------------------------------------------------------------------------*/
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void
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mtarch_pstop(void)
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{
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}
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/*--------------------------------------------------------------------------*/
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void
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mtarch_pstart(void)
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{
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}
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/*--------------------------------------------------------------------------*/
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int
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mtarch_stack_usage(struct mt_thread *t)
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{
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uint8_t i;
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for(i = 0; i < MTARCH_STACKSIZE; ++i) {
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if(t->thread.stack[i] != i) {
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break;
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}
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}
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return MTARCH_STACKSIZE - i;
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}
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/*--------------------------------------------------------------------------*/
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