xref: /dports/misc/gpsim/gpsim-0.31.0/src/psp.cc

/*
   Copyright (C) 2006 Roy R Rankin

This file is part of the libgpsim library of gpsim

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see
<http://www.gnu.org/licenses/lgpl-2.1.html>.
*/

#include <assert.h>
#include <stdio.h>
#include <iostream>
#include "../config.h"
#include "stimuli.h"
#include "psp.h"

//#define DEBUG
#if defined(DEBUG)
#define Dprintf(arg) {printf("%s:%d-%s() ",__FILE__,__LINE__,__FUNCTION__); printf arg; }
#else
#define Dprintf(arg) {}
#endif

//--------------------------------------------------
//
//--------------------------------------------------


class CS_SignalSink : public SignalSink {
public:
  explicit CS_SignalSink(PSP *_psp)
    : m_psp(_psp)
  {
    assert(_psp);
  }
  virtual void release()
  {
    delete this;
  }

  void setSinkState(char new3State)
  {
    m_psp->setCS_State(new3State);
  }

private:
  PSP *m_psp;
};


class RD_SignalSink : public SignalSink {
public:
  explicit RD_SignalSink(PSP *_psp)
    : m_psp(_psp)
  {
    assert(_psp);
  }
  virtual void release()
  {
    delete this;
  }

  void setSinkState(char new3State)
  {
    m_psp->setRD_State(new3State);
  }

private:
  PSP *m_psp;
};


class WR_SignalSink : public SignalSink {
public:
  explicit WR_SignalSink(PSP *_psp)
    : m_psp(_psp)
  {
    assert(_psp);
  }
  virtual void release()
  {
    delete this;
  }

  void setSinkState(char new3State)
  {
    m_psp->setWR_State(new3State);
  }

private:
  PSP *m_psp;
};


/*
 * Some devices use high bits of a TRIS register, but others
 * have a dedicated PSPCON register which is defined here
 */

PSPCON::PSPCON(Processor *pCpu, const char *pName, const char *pDesc)
  : sfr_register(pCpu, pName, pDesc)
{
}


void PSPCON::put(unsigned int new_value)
{
  unsigned int mask = (PSP::OBF | PSP::IBF | 0x0f);
  unsigned int fixed;
  trace.raw(write_trace.get() | value.data);

  if (!(new_value & PSP::PSPMODE)) {
    fixed = 0;

  } else {
    fixed = value.data & mask;
  }

  value.data = (new_value & ~mask) | fixed;
}


void PSPCON::put_value(unsigned int new_value)
{
  trace.raw(write_trace.get() | value.data);
  value.data = new_value;
}


//
// setup information for PSP module
//
void PSP::initialize(PIR_SET *_pir_set, PicPSP_PortRegister *_port_set,
                     PicTrisRegister *_port_tris, sfr_register *_pspcon,
                     PinModule *pin_RD, PinModule *pin_WR, PinModule *pin_CS)
{
  if (verbose & 2) {
    std::cout << "PSP::initialize called\n";
  }

  pir_set = _pir_set;
  parallel_port = _port_set;
  parallel_port->setPSP(this);
  parallel_tris = _port_tris;
  cntl_tris = _pspcon;

  //
  // The rest of this function allows catching of changes to PSP contol signals
  //
  if (!m_rd_sink) {
    m_rd_sink = new RD_SignalSink(this);
    Not_RD = pin_RD;

    if (Not_RD) {
      Not_RD->addSink(m_rd_sink);
    }
  }

  if (!m_cs_sink) {
    m_cs_sink = new CS_SignalSink(this);
    Not_CS = pin_CS;

    if (Not_CS) {
      Not_CS->addSink(m_cs_sink);
    }
  }

  if (!m_wr_sink) {
    m_wr_sink = new WR_SignalSink(this);
    Not_WR = pin_WR;

    if (Not_WR) {
      Not_WR->addSink(m_wr_sink);
    }
  }
}


//
// process changes on the control pins
//
void PSP::state_control()
{
  if (! pspmode()) {
    return;
  }

  if (verbose & 2) {
    std::cout << "PSP state change cs=" << cs << " wr=" << wr << " rd=" << rd << '\n';
  }

  if (rd && wr && cs) {	// this is an error condition
    std::cerr << "PSP: Error CS, WR and RD must not all be low\n";
    parallel_tris->put(0xff);
    state = ST_INACTIVE;
    return;

  } else if (cs && rd) {
    parallel_tris->put(0);
    parallel_port->put_value(put_value);
    cntl_tris->put_value(cntl_tris->get() & ~OBF);
    state = ST_READ;

  } else if (cs && wr) {
    parallel_tris->put(0xff);
    get_value = parallel_port->get_value();
    state = ST_WRITE;

  } else {
    if (state != ST_INACTIVE) {
      pir_set->set_pspif();
    }

    //
    // On first bus write set IBF flag.
    // if a second bus write occurs prior to read of pic port (portd)
    // IBOV flag is also set.
    //
    if (state == ST_WRITE) {
      unsigned int trise_val = cntl_tris->get();

      if (trise_val & IBF) {
        cntl_tris->put_value(trise_val | IBOV);

      } else {
        cntl_tris->put_value(trise_val | IBF);
      }
    }

    parallel_tris->put(0xff);
    state = ST_INACTIVE;
  }
}


//
// The next three functions are called when their control pin change state
// The control pins are active low which is converted to active high signals
void PSP::setRD_State(char new3State)
{
  rd = new3State == '0';
  state_control();
}


void PSP::setCS_State(char new3State)
{
  cs = new3State == '0';
  state_control();
}


void PSP::setWR_State(char new3State)
{
  wr = new3State == '0';
  state_control();
}


//
// psp_put is called on write to portd when pspmode is active
// set OBF register bit and save value for next bus read
//
void PSP::psp_put(unsigned int new_value)
{
  cntl_tris->put_value(cntl_tris->get() | OBF);
  put_value = new_value;
}


//
// psp_get is called on read of portd when pspmode is active so
// we can clear the IBF flag
//
unsigned int PSP::psp_get()
{
  cntl_tris->put_value(cntl_tris->get() & ~IBF);
  return get_value;
}