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/* except.c -- Simulation of OR1K exceptions

   Copyright (C) 1999 Damjan Lampret, lampret@opencores.org

This file is part of OpenRISC 1000 Architectural Simulator.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include "config.h"

#ifdef HAVE_INTTYPES_H

#include <inttypes.h>

#endif

#include "port.h"

#include "arch.h"

#include "abstract.h"

#include "except.h"

#include "sim-config.h"

#include "debug_unit.h"

#include "opcode/or32.h"

#include "spr_defs.h"

#include "execute.h"

#include "sprs.h"

#include "debug.h"

#if DYNAMIC_EXECUTION

#include "sched.h"

#include "op_support.h"

#endif

DEFAULT_DEBUG_CHANNEL(except);

int except_pending = 0;

static const char *except_names[] = {

 NULL,

 "Reset",

 "Bus Error",

 "Data Page Fault",

 "Insn Page Fault",

 "Tick timer",

 "Alignment",

 "Illegal instruction",

 "Interrupt",

 "Data TLB Miss",

 "Insn TLB Miss",

 "Range",

 "System Call",

 "Floating Point",

 "Trap" };

const char *except_name(oraddr_t except)

{

  return except_names[except >> 8];

}

/* Asserts OR1K exception. */

/* WARNING: Don't excpect except_handle to return.  Sometimes it _may_ return at

 * other times it may not. */

void except_handle(oraddr_t except, oraddr_t ea)

{

  oraddr_t except_vector;

  if(debug_ignore_exception (except))

    return;

#if !(DYNAMIC_EXECUTION)

  /* In the dynamic recompiler, this function never returns, so this is not

   * needed.  Ofcourse we could set it anyway, but then all code that checks

   * this variable would break, since it is never reset */

  except_pending = 1;

#endif

  TRACE("Exception 0x%"PRIxADDR" (%s) at 0x%"PRIxADDR", EA: 0x%"PRIxADDR

        ", cycles %lld, #%lld\n",

        except, except_name(except), cpu_state.pc, ea, runtime.sim.cycles,

        runtime.cpu.instructions);

  except_vector = except + (cpu_state.sprs[SPR_SR] & SPR_SR_EPH ? 0xf0000000 : 0x00000000);

#if !(DYNAMIC_EXECUTION)

  pcnext = except_vector;

#endif

  cpu_state.sprs[SPR_EEAR_BASE] =  ea;

  cpu_state.sprs[SPR_ESR_BASE] = cpu_state.sprs[SPR_SR];

  cpu_state.sprs[SPR_SR] &= ~SPR_SR_OVE;   /* Disable overflow flag exception. */

  cpu_state.sprs[SPR_SR] |= SPR_SR_SM;    /* SUPV mode */

  cpu_state.sprs[SPR_SR] &= ~(SPR_SR_IEE | SPR_SR_TEE);   /* Disable interrupts. */

  /* Address translation is always disabled when starting exception. */

  cpu_state.sprs[SPR_SR] &= ~SPR_SR_DME;

#if DYNAMIC_EXECUTION

  /* If we were called from do_scheduler and there were more jobs scheduled to

   * run after this, they won't run unless the following call is made since this

   * function never returns.  (If we weren't called from do_scheduler, then the

   * job at the head of the queue will still have some time remaining) */

  if(scheduler.job_queue->time <= 0)

    do_scheduler();

#endif

  switch(except) {

  /* EPCR is irrelevent */

  case EXCEPT_RESET:

    break;

  /* EPCR is loaded with address of instruction that caused the exception */

  case EXCEPT_ITLBMISS:

  case EXCEPT_IPF:

    cpu_state.sprs[SPR_EPCR_BASE] = ea - (cpu_state.delay_insn ? 4 : 0);

#if DYNAMIC_EXECUTION

    op_join_mem_cycles();

#endif

    break;

  case EXCEPT_BUSERR:

  case EXCEPT_DPF:

  case EXCEPT_ALIGN:

  case EXCEPT_ILLEGAL:

  case EXCEPT_DTLBMISS:

  case EXCEPT_RANGE:

  case EXCEPT_TRAP:

    /* All these exceptions happen during a simulated instruction */

#if DYNAMIC_EXECUTION

    /* Since these exceptions happen during a simulated instruction and this

     * function jumps out to the exception vector the scheduler would never have

     * a chance to run, therefore run it now */

    run_sched_out_of_line();

#endif

    cpu_state.sprs[SPR_EPCR_BASE] = cpu_state.pc - (cpu_state.delay_insn ? 4 : 0);

    break;

  /* EPCR is loaded with address of next not-yet-executed instruction */

  case EXCEPT_SYSCALL:

    cpu_state.sprs[SPR_EPCR_BASE] = (cpu_state.pc + 4) - (cpu_state.delay_insn ? 4 : 0);

    break;

  /* These exceptions happen AFTER (or before) an instruction has been

   * simulated, therefore the pc already points to the *next* instruction */

  case EXCEPT_TICK:

  case EXCEPT_INT:

    cpu_state.sprs[SPR_EPCR_BASE] = cpu_state.pc - (cpu_state.delay_insn ? 4 : 0);

#if !(DYNAMIC_EXECUTION)

    /* If we don't update the pc now, then it will only happen *after* the next

     * instruction (There would be serious problems if the next instruction just

     * happens to be a branch), when it should happen NOW. */

    cpu_state.pc = pcnext;

    pcnext += 4;

#endif

    break;

  }

  /* Address trnaslation is here because run_sched_out_of_line calls

   * eval_insn_direct which checks out the immu for the address translation but

   * if it would be disabled above then there would be not much point... */

  cpu_state.sprs[SPR_SR] &= ~SPR_SR_IME;

  /* Complex/simple execution strictly don't need this because of the

   * next_delay_insn thingy but in the dynamic execution modell that doesn't

   * exist and thus cpu_state.delay_insn would stick in the exception handler

   * causeing grief if the first instruction of the exception handler is also in

   * the delay slot of the previous instruction */

  cpu_state.delay_insn = 0;

#if DYNAMIC_EXECUTION

  do_jump(except_vector);

#endif

}