/*  armcopro.c -- co-processor interface:  ARM6 Instruction Emulator.
    Copyright (C) 1994 Advanced RISC Machines Ltd.
 
    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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */

#include "armdefs.h"

extern unsigned ARMul_CoProInit (ARMul_State * state);
extern void ARMul_CoProExit (ARMul_State * state);
extern void ARMul_CoProAttach (ARMul_State * state, unsigned number,
			       ARMul_CPInits * init, ARMul_CPExits * exit,
			       ARMul_LDCs * ldc, ARMul_STCs * stc,
			       ARMul_MRCs * mrc, ARMul_MCRs * mcr,
			       ARMul_CDPs * cdp,
			       ARMul_CPReads * read, ARMul_CPWrites * write);
extern void ARMul_CoProDetach (ARMul_State * state, unsigned number);


/***************************************************************************\
*                            Dummy Co-processors                            *
\***************************************************************************/

static unsigned NoCoPro3R (ARMul_State * state, unsigned, ARMword);
static unsigned NoCoPro4R (ARMul_State * state, unsigned, ARMword, ARMword);
static unsigned NoCoPro4W (ARMul_State * state, unsigned, ARMword, ARMword *);

/***************************************************************************\
*                Define Co-Processor instruction handlers here              *
\***************************************************************************/

/* Here's ARMulator's MMU definition.  A few things to note:
1) it has eight registers, but only two are defined.
2) you can only access its registers with MCR and MRC.
3) MMU Register 0 (ID) returns 0x41440110
4) Register 1 only has 4 bits defined.  Bits 0 to 3 are unused, bit 4
controls 32/26 bit program space, bit 5 controls 32/26 bit data space,
bit 6 controls late abort timimg and bit 7 controls big/little endian.
*/

static ARMword MMUReg[8];

static unsigned
MMUInit (ARMul_State * state)
{
  MMUReg[1] = state->prog32Sig << 4 |
    state->data32Sig << 5 | state->lateabtSig << 6 | state->bigendSig << 7;
  ARMul_ConsolePrint (state, ", MMU present");
  return (TRUE);
}

static unsigned
MMUMRC (ARMul_State * state, unsigned type, ARMword instr, ARMword * value)
{
  int reg = BITS (16, 19) & 7;

  if (reg == 0)
    *value = 0x41440110;
  else
    *value = MMUReg[reg];
  return (ARMul_DONE);
}

static unsigned
MMUMCR (ARMul_State * state, unsigned type, ARMword instr, ARMword value)
{
  int reg = BITS (16, 19) & 7;

  MMUReg[reg] = value;
  if (reg == 1)
    {
      state->prog32Sig = value >> 4 & 1;
      state->data32Sig = value >> 5 & 1;
      state->lateabtSig = value >> 6 & 1;
      state->bigendSig = value >> 7 & 1;
      state->Emulate = TRUE;	/* force ARMulator to notice these now ! */
    }
  return (ARMul_DONE);
}


static unsigned
MMURead (ARMul_State * state, unsigned reg, ARMword * value)
{
  if (reg == 0)
    *value = 0x41440110;
  else if (reg < 8)
    *value = MMUReg[reg];
  return (TRUE);
}

static unsigned
MMUWrite (ARMul_State * state, unsigned reg, ARMword value)
{
  if (reg < 8)
    MMUReg[reg] = value;
  if (reg == 1)
    {
      state->prog32Sig = value >> 4 & 1;
      state->data32Sig = value >> 5 & 1;
      state->lateabtSig = value >> 6 & 1;
      state->bigendSig = value >> 7 & 1;
      state->Emulate = TRUE;	/* force ARMulator to notice these now ! */
    }
  return (TRUE);
}


/* What follows is the Validation Suite Coprocessor.  It uses two
co-processor numbers (4 and 5) and has the follwing functionality.
Sixteen registers.  Both co-processor nuimbers can be used in an MCR and
MRC to access these registers.  CP 4 can LDC and STC to and from the
registers.  CP 4 and CP 5 CDP 0 will busy wait for the number of cycles
specified by a CP register.  CP 5 CDP 1 issues a FIQ after a number of
cycles (specified in a CP register), CDP 2 issues an IRQW in the same
way, CDP 3 and 4 turn of the FIQ and IRQ source, and CDP 5 stores a 32
bit time value in a CP register (actually it's the total number of N, S,
I, C and F cyles) */

static ARMword ValReg[16];

static unsigned
ValLDC (ARMul_State * state, unsigned type, ARMword instr, ARMword data)
{
  static unsigned words;

  if (type != ARMul_DATA)
    {
      words = 0;
      return (ARMul_DONE);
    }
  if (BIT (22))
    {				/* it's a long access, get two words */
      ValReg[BITS (12, 15)] = data;
      if (words++ == 4)
	return (ARMul_DONE);
      else
	return (ARMul_INC);
    }
  else
    {				/* get just one word */
      ValReg[BITS (12, 15)] = data;
      return (ARMul_DONE);
    }
}

static unsigned
ValSTC (ARMul_State * state, unsigned type, ARMword instr, ARMword * data)
{
  static unsigned words;

  if (type != ARMul_DATA)
    {
      words = 0;
      return (ARMul_DONE);
    }
  if (BIT (22))
    {				/* it's a long access, get two words */
      *data = ValReg[BITS (12, 15)];
      if (words++ == 4)
	return (ARMul_DONE);
      else
	return (ARMul_INC);
    }
  else
    {				/* get just one word */
      *data = ValReg[BITS (12, 15)];
      return (ARMul_DONE);
    }
}

static unsigned
ValMRC (ARMul_State * state, unsigned type, ARMword instr, ARMword * value)
{
  *value = ValReg[BITS (16, 19)];
  return (ARMul_DONE);
}

static unsigned
ValMCR (ARMul_State * state, unsigned type, ARMword instr, ARMword value)
{
  ValReg[BITS (16, 19)] = value;
  return (ARMul_DONE);
}

static unsigned
ValCDP (ARMul_State * state, unsigned type, ARMword instr)
{
  static unsigned long finish = 0;
  ARMword howlong;

  howlong = ValReg[BITS (0, 3)];
  if (BITS (20, 23) == 0)
    {
      if (type == ARMul_FIRST)
	{			/* First cycle of a busy wait */
	  finish = ARMul_Time (state) + howlong;
	  if (howlong == 0)
	    return (ARMul_DONE);
	  else
	    return (ARMul_BUSY);
	}
      else if (type == ARMul_BUSY)
	{
	  if (ARMul_Time (state) >= finish)
	    return (ARMul_DONE);
	  else
	    return (ARMul_BUSY);
	}
    }
  return (ARMul_CANT);
}

static unsigned
DoAFIQ (ARMul_State * state)
{
  state->NfiqSig = LOW;
  state->Exception++;
  return (0);
}

static unsigned
DoAIRQ (ARMul_State * state)
{
  state->NirqSig = LOW;
  state->Exception++;
  return (0);
}

static unsigned
IntCDP (ARMul_State * state, unsigned type, ARMword instr)
{
  static unsigned long finish;
  ARMword howlong;

  howlong = ValReg[BITS (0, 3)];
  switch ((int) BITS (20, 23))
    {
    case 0:
      if (type == ARMul_FIRST)
	{			/* First cycle of a busy wait */
	  finish = ARMul_Time (state) + howlong;
	  if (howlong == 0)
	    return (ARMul_DONE);
	  else
	    return (ARMul_BUSY);
	}
      else if (type == ARMul_BUSY)
	{
	  if (ARMul_Time (state) >= finish)
	    return (ARMul_DONE);
	  else
	    return (ARMul_BUSY);
	}
      return (ARMul_DONE);
    case 1:
      if (howlong == 0)
	ARMul_Abort (state, ARMul_FIQV);
      else
	ARMul_ScheduleEvent (state, howlong, DoAFIQ);
      return (ARMul_DONE);
    case 2:
      if (howlong == 0)
	ARMul_Abort (state, ARMul_IRQV);
      else
	ARMul_ScheduleEvent (state, howlong, DoAIRQ);
      return (ARMul_DONE);
    case 3:
      state->NfiqSig = HIGH;
      state->Exception--;
      return (ARMul_DONE);
    case 4:
      state->NirqSig = HIGH;
      state->Exception--;
      return (ARMul_DONE);
    case 5:
      ValReg[BITS (0, 3)] = ARMul_Time (state);
      return (ARMul_DONE);
    }
  return (ARMul_CANT);
}

/***************************************************************************\
*         Install co-processor instruction handlers in this routine         *
\***************************************************************************/

unsigned
ARMul_CoProInit (ARMul_State * state)
{
  register unsigned i;

  for (i = 0; i < 16; i++)	/* initialise tham all first */
    ARMul_CoProDetach (state, i);

  /* Install CoPro Instruction handlers here
     The format is
     ARMul_CoProAttach(state, CP Number, Init routine, Exit routine
     LDC routine, STC routine, MRC routine, MCR routine,
     CDP routine, Read Reg routine, Write Reg routine) ;
   */

  ARMul_CoProAttach (state, 4, NULL, NULL,
		     ValLDC, ValSTC, ValMRC, ValMCR, ValCDP, NULL, NULL);

  ARMul_CoProAttach (state, 5, NULL, NULL,
		     NULL, NULL, ValMRC, ValMCR, IntCDP, NULL, NULL);

  ARMul_CoProAttach (state, 15, MMUInit, NULL,
		     NULL, NULL, MMUMRC, MMUMCR, NULL, MMURead, MMUWrite);


  /* No handlers below here */

  for (i = 0; i < 16; i++)	/* Call all the initialisation routines */
    if (state->CPInit[i])
      (state->CPInit[i]) (state);
  return (TRUE);
}

/***************************************************************************\
*         Install co-processor finalisation routines in this routine        *
\***************************************************************************/

void
ARMul_CoProExit (ARMul_State * state)
{
  register unsigned i;

  for (i = 0; i < 16; i++)
    if (state->CPExit[i])
      (state->CPExit[i]) (state);
  for (i = 0; i < 16; i++)	/* Detach all handlers */
    ARMul_CoProDetach (state, i);
}

/***************************************************************************\
*              Routines to hook Co-processors into ARMulator                 *
\***************************************************************************/

void
ARMul_CoProAttach (ARMul_State * state, unsigned number,
		   ARMul_CPInits * init, ARMul_CPExits * exit,
		   ARMul_LDCs * ldc, ARMul_STCs * stc,
		   ARMul_MRCs * mrc, ARMul_MCRs * mcr, ARMul_CDPs * cdp,
		   ARMul_CPReads * read, ARMul_CPWrites * write)
{
  if (init != NULL)
    state->CPInit[number] = init;
  if (exit != NULL)
    state->CPExit[number] = exit;
  if (ldc != NULL)
    state->LDC[number] = ldc;
  if (stc != NULL)
    state->STC[number] = stc;
  if (mrc != NULL)
    state->MRC[number] = mrc;
  if (mcr != NULL)
    state->MCR[number] = mcr;
  if (cdp != NULL)
    state->CDP[number] = cdp;
  if (read != NULL)
    state->CPRead[number] = read;
  if (write != NULL)
    state->CPWrite[number] = write;
}

void
ARMul_CoProDetach (ARMul_State * state, unsigned number)
{
  ARMul_CoProAttach (state, number, NULL, NULL,
		     NoCoPro4R, NoCoPro4W, NoCoPro4W, NoCoPro4R,
		     NoCoPro3R, NULL, NULL);
  state->CPInit[number] = NULL;
  state->CPExit[number] = NULL;
  state->CPRead[number] = NULL;
  state->CPWrite[number] = NULL;
}

/***************************************************************************\
*         There is no CoPro around, so Undefined Instruction trap           *
\***************************************************************************/

static unsigned
NoCoPro3R (ARMul_State * state, unsigned a, ARMword b)
{
  return (ARMul_CANT);
}

static unsigned
NoCoPro4R (ARMul_State * state, unsigned a, ARMword b, ARMword c)
{
  return (ARMul_CANT);
}

static unsigned
NoCoPro4W (ARMul_State * state, unsigned a, ARMword b, ARMword * c)
{
  return (ARMul_CANT);
}