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2179 stepan 1
    /*
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 * Copyright (c) 2007 Petr Stepan
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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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 *
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 * - 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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 * - 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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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * 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
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/** @addtogroup arm32
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 * @{
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 */
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/** @file
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    @brief  Exception handlers and exception initialization routines.
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 */
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#include <arch/exception.h>
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#include "aux_print/printf.h"
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#include <arch/memstr.h>
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#define PREFETCH_OFFSET     0x8
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#define BRANCH_OPCODE       0xea000000
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#define VALID_BRANCH_MASK   0xff000000
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/** Updates specified exception vector to jump to given handler.
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*/
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static void install_handler (unsigned* handler, unsigned* vector) {
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    volatile unsigned vec;
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    /* calculate relative distance */
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    vec = ((unsigned)handler - (unsigned)vector - PREFETCH_OFFSET);
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    /* word offset */
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    vec >>= 2;
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    /* check if haven't jumped beyond 32 MB */
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    if ((vec & VALID_BRANCH_MASK) != 0) {
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        /*panic("exception handler beyond 32MB.");*/
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        return;
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    }
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    /* make it branch instruction */
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    vec |= BRANCH_OPCODE;
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    *vector = vec;
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    aux_printf("installed  handler to %p, to vector %p\n.", handler, vector);
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}
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/* TODO add other exception handlers */
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static void dummy_exception(){
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    asm("bkpt");
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}
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/** IRQ Exception handler */
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static void irq_exception(){
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    asm("bkpt");
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}
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/** Fills exception vectors with appropriate exception handlers.
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*/
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void install_exception_handlers(void) {
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    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_RESET_VEC);
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    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_UNDEF_INSTR_VEC);
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    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_SWI_VEC);
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    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_PREFETCH_ABORT_VEC);
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    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_DATA_ABORT_VEC);
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    install_handler((unsigned*)irq_exception,   (unsigned*)EXC_IRQ_VEC);
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    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_FIQ_VEC);
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}
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/** Registers exceptions and their handlers to kernel exception dispatcher. */
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void exception_init(void){
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    /* TODO */
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}
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/** @}
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 */