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/* libtoplevel.c -- Top level simulator library source file
 
   Copyright (C) 1999 Damjan Lampret, lampret@opencores.org
   Copyright (C) 2008 Embecosm Limited
 
   Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>
 
   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 3 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, see <http://www.gnu.org/licenses/>. */
 
/* This program is commented throughout in a fashion suitable for processing
   with Doxygen. */
 
 
/* Autoconf and/or portability configuration */
#include "config.h"
 
/* System includes */
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
 
/* Package includes */
#include "or1ksim.h"
#include "sim-config.h"
#include "toplevel-support.h"
#include "sched.h"
#include "execute.h"
#include "pic.h"
#include "jtag.h"
 
/* Indices of GDB registers that are not GPRs. Must match GDB settings! */
#define MAX_GPRS    32			/*!< Maximum GPRs */
#define PPC_REGNUM  (MAX_GPRS + 0)	/*!< Previous PC */
#define NPC_REGNUM  (MAX_GPRS + 1)	/*!< Next PC */
#define SR_REGNUM   (MAX_GPRS + 2)	/*!< Supervision Register */
 
 
/*---------------------------------------------------------------------------*/
/*!Initialize the simulator. 
 
   Allows specification of an (optional) config file and an image file. Builds
   up dummy argc/argv to pass to the existing argument parser.
 
   @param[in] config_file  Or1ksim configuration file name
   @param[in] image_file   The program image to execute
   @param[in] class_ptr    Pointer to a C++ class instance (for use when
                           called by C++)
   @param[in] upr          Upcall routine for reads
   @param[in] upw          Upcall routine for writes
 
   @return  0 on success and an error code on failure                        */
/*---------------------------------------------------------------------------*/
int
or1ksim_init (const char *config_file,
	      const char *image_file,
	      void       *class_ptr,
	      int       (*upr) (void              *class_ptr,
				unsigned long int  addr,
				unsigned char      mask[],
				unsigned char      rdata[],
				int                data_len),
	      int       (*upw) (void              *class_ptr,
				unsigned long int  addr,
				unsigned char      mask[],
				unsigned char      wdata[],
				int                data_len))
{
  int   dummy_argc;
  char *dummy_argv[4];
 
  /* Dummy argv array. Varies depending on whether an image file is
     specified. */
  dummy_argv[0] = "libsim";
  dummy_argv[1] = "-f";
  dummy_argv[2] = (char *) ((NULL != config_file) ? config_file : "sim.cfg");
  dummy_argv[3] = (char *) image_file;
 
  dummy_argc = (NULL == image_file) ? 3 : 4;
 
  /* Initialization copied from existing main() */
  srand (getpid ());
  init_defconfig ();
  reg_config_secs ();
 
  if (parse_args (dummy_argc, dummy_argv))
    {
      return OR1KSIM_RC_BADINIT;
    }
 
  config.sim.is_library = 1;	/* Library operation */
  config.sim.profile    = 0;	/* No profiling */
  config.sim.mprofile   = 0;
 
  config.ext.class_ptr  = class_ptr;	/* SystemC linkage */
  config.ext.read_up    = upr;
  config.ext.write_up   = upw;
 
  print_config ();		/* Will go eventually */
  signal (SIGINT, ctrl_c);	/* Not sure we want this really */
 
  runtime.sim.hush = 1;		/* Not sure if this is needed */
  do_stats = config.cpu.superscalar ||
             config.cpu.dependstats ||
             config.sim.history     ||
             config.sim.exe_log;
 
  sim_init ();
 
  runtime.sim.ext_int_set = 0;	/* No interrupts pending to be set */
  runtime.sim.ext_int_clr = 0;	/* No interrupts pending to be cleared */
 
  return OR1KSIM_RC_OK;
 
}	/* or1ksim_init () */
 
 
/*---------------------------------------------------------------------------*/
/*!Run the simulator
 
   The argument is a time in seconds, which is converted to a number of
   cycles, if positive. A negative value means "run for ever".
 
   With the JTAG interface, it is possible to stall the processor between
   calls of this function (but not during upcalls). In which case we return
   immediately.
 
   @todo Is it possible (or desirable) to permit JTAG activity during upcalls,
         in which case we could stall mid-run.
 
   @todo Should the JTAG functionality require enabling?
 
   The semantics are that the duration for which the run may occur may be
   changed mid-run by a call to or1ksim_reset_duration(). This is to allow for
   the upcalls to generic components adding time, and reducing the time
   permitted for ISS execution before synchronization of the parent SystemC
   wrapper.
 
   This is over-ridden if the call was for a negative duration, which means
   run forever!
 
   Uses a simplified version of the old main program loop. Returns success if
   the requested number of cycles were run and an error code otherwise.
 
   @param[in] duration  Time to execute for (seconds)
 
   @return  OR1KSIM_RC_OK if we run to completion, OR1KSIM_RC_BRKPT if we hit
            a breakpoint (not clear how this can be set without CLI access)  */
/*---------------------------------------------------------------------------*/
int
or1ksim_run (double duration)
{
  const int  num_ints = sizeof (runtime.sim.ext_int_set) * 8;
 
  /* If we are stalled we can't do anything. We treat this as hitting a
     breakpoint or halting. */
  if(runtime.cpu.stalled)
    {
      return runtime.cpu.halted ? OR1KSIM_RC_HALTED : OR1KSIM_RC_BRKPT;
    }
 
  /* Reset the duration */
  or1ksim_reset_duration (duration);
 
  /* Loop until we have done enough cycles (or forever if we had a negative
     duration) */
  while (duration < 0.0 || (runtime.sim.cycles < runtime.sim.end_cycles))
    {
      long long int time_start = runtime.sim.cycles;
      int i;			/* Interrupt # */
 
      /* Each cycle has counter of mem_cycles; this value is joined with cycles
       * at the end of the cycle; no sim originated memory accesses should be
       * performed in between. */
      runtime.sim.mem_cycles = 0;
 
      if (cpu_clock ())
	{
	  /* This is probably wrong. This is an Or1ksim breakpoint, not a GNU
	     one. */
	  return runtime.cpu.halted ? OR1KSIM_RC_HALTED : OR1KSIM_RC_BRKPT;
	}
 
      /* If we are stalled we can't do anything. We treat this as hitting a
	 breakpoint or halting. */
      if(runtime.cpu.stalled)
	{
	  return runtime.cpu.halted ? OR1KSIM_RC_HALTED : OR1KSIM_RC_BRKPT;
	}
 
      runtime.sim.cycles += runtime.sim.mem_cycles;
 
      /* Take any external interrupts. Outer test is for the common case for
         efficiency. */
      if (0 != runtime.sim.ext_int_set)
	{
	  for (i = 0; i < num_ints; i++)
	    {
	      if (0x1 == ((runtime.sim.ext_int_set >> i) & 0x1))
		{
		  report_interrupt (i);
		  runtime.sim.ext_int_set &= ~(1 << i);	/* Clear req flag */
		}
	    }
	}
 
      /* Clear any interrupts as requested. For edge triggered interrupts this
	 will happen in the same cycle. For level triggered, it must be an
	 explicit call. */
      if (0 != runtime.sim.ext_int_clr)
	{
	  for (i = 0; i < num_ints; i++)
	    {
	      /* Only clear interrupts that have been explicitly cleared */
	      if(0x1 == ((runtime.sim.ext_int_clr >> i) & 0x1))
		{
		  clear_interrupt(i);
		  runtime.sim.ext_int_clr &= ~(1 << i); /* Clear clr flag */
		}
	    }
	}
 
      /* Update the scheduler queue */
      scheduler.job_queue->time -= (runtime.sim.cycles - time_start);
 
      if (scheduler.job_queue->time <= 0)
	{
	  do_scheduler ();
	}
    }
 
  return  OR1KSIM_RC_OK;
 
}	/* or1ksim_run () */
 
 
/*---------------------------------------------------------------------------*/
/*!Step the simulator
 
   This is just a wrapper for the run function, specifying a time
   corresponding to a single cycle. This will in fact mean that a single
   instruction is executed, even if takes more than one cycle to execute.
 
   @todo What happens if an event is triggered - that may mean multiple
         instructions.
 
   @return  OR1KSIM_RC_OK if we step to completion, OR1KSIM_RC_BRKPT if we hit
            a breakpoint (not clear how this can be set without CLI access)  */
/*---------------------------------------------------------------------------*/
int
or1ksim_step ()
{
  return  or1ksim_run ((double) config.sim.clkcycle_ps / 1e12);
 
}	/* or1ksim_step () */
 
 
/*---------------------------------------------------------------------------*/
/*!Reset the run-time simulation end point
 
  Reset the time for which the simulation should run to the specified duration
  from NOW (i.e. NOT from when the run started).
 
  @param[in] duration  Time to run for in seconds                            */
/*---------------------------------------------------------------------------*/
void
or1ksim_reset_duration (double duration)
{
  runtime.sim.end_cycles =
    runtime.sim.cycles +
    (long long int) (duration * 1.0e12 / (double) config.sim.clkcycle_ps);
 
}	/* or1ksim_reset_duration () */
 
 
/*---------------------------------------------------------------------------*/
/*!Return time executed so far
 
   Internal utility to return the time executed so far. Note that this is a
   re-entrant routine.
 
   @return  Time executed so far in seconds                                  */
/*---------------------------------------------------------------------------*/
static double
internal_or1ksim_time ()
{
  return (double) runtime.sim.cycles * (double) config.sim.clkcycle_ps /
    1.0e12;
 
}	// or1ksim_cycle_count()
 
 
/*---------------------------------------------------------------------------*/
/*!Mark a time point in the simulation
 
   Sets the internal parameter recording this point in the simulation        */
/*---------------------------------------------------------------------------*/
void
or1ksim_set_time_point ()
{
  runtime.sim.time_point = internal_or1ksim_time ();
 
}	/* or1ksim_set_time_point () */
 
 
/*---------------------------------------------------------------------------*/
/*!Return the time since the time point was set
 
  Get the value from the internal parameter                                  */
/*---------------------------------------------------------------------------*/
double
or1ksim_get_time_period ()
{
  return internal_or1ksim_time () - runtime.sim.time_point;
 
}	/* or1ksim_get_time_period () */
 
 
/*---------------------------------------------------------------------------*/
/*!Return the endianism of the model
 
   Note that this is a re-entrant routine.
 
   @return 1 if the model is little endian, 0 otherwise.                     */
/*---------------------------------------------------------------------------*/
int
or1ksim_is_le ()
{
#ifdef OR32_BIG_ENDIAN
  return 0;
#else
  return 1;
#endif
 
}	/* or1ksim_is_le () */
 
 
/*---------------------------------------------------------------------------*/
/*!Return the clock rate
 
   Value is part of the configuration
 
   @return  Clock rate in Hz.                                                */
/*---------------------------------------------------------------------------*/
unsigned long int
or1ksim_clock_rate ()
{
  return (unsigned long int) (1000000000000ULL /
			      (unsigned long long int) (config.sim.
							clkcycle_ps));
}	/* or1ksim_clock_rate () */
 
 
/*---------------------------------------------------------------------------*/
/*!Trigger an edge triggered interrupt
 
   This function is appropriate for edge triggered interrupts, which are taken
   and then immediately cleared.
 
   @note There is no check that the specified interrupt number is reasonable
   (i.e. <= 31).
 
   @param[in] i  The interrupt number                                        */
/*---------------------------------------------------------------------------*/
void
or1ksim_interrupt (int i)
{
  if (!config.pic.edge_trigger)
    {
      fprintf (stderr, "Warning: or1ksim_interrupt should not be used for "
	       "level triggered interrupts. Ignored\n");
    }
  else
    {
      runtime.sim.ext_int_set |= 1 << i;	// Better not be > 31!
      runtime.sim.ext_int_clr |= 1 << i;	// Better not be > 31!
    }
}	/* or1ksim_interrupt () */
 
 
/*---------------------------------------------------------------------------*/
/*!Set a level triggered interrupt
 
   This function is appropriate for level triggered interrupts, which must be
   explicitly cleared in a separate call.
 
   @note There is no check that the specified interrupt number is reasonable
   (i.e. <= 31).
 
   @param[in] i  The interrupt number to set                                 */
/*---------------------------------------------------------------------------*/
void
or1ksim_interrupt_set (int i)
{
  if (config.pic.edge_trigger)
    {
      fprintf (stderr, "Warning: or1ksim_interrupt_set should not be used for "
	       "edge triggered interrupts. Ignored\n");
    }
  else
    {
      runtime.sim.ext_int_set |= 1 << i;	// Better not be > 31!
    }
}	/* or1ksim_interrupt () */
 
 
/*---------------------------------------------------------------------------*/
/*!Clear a level triggered interrupt
 
   This function is appropriate for level triggered interrupts, which must be
   explicitly set first in a separate call.
 
   @note There is no check that the specified interrupt number is reasonable
   (i.e. <= 31).
 
   @param[in] i  The interrupt number to clear                               */
/*---------------------------------------------------------------------------*/
void
or1ksim_interrupt_clear (int i)
{
  if (config.pic.edge_trigger)
    {
      fprintf (stderr, "Warning: or1ksim_interrupt_clear should not be used "
	       "for edge triggered interrupts. Ignored\n");
    }
  else
    {
      runtime.sim.ext_int_clr |= 1 << i;	// Better not be > 31!
    }
}	/* or1ksim_interrupt () */
 
 
/*---------------------------------------------------------------------------*/
/*!Reset the JTAG interface
 
   @note Like all the JTAG interface functions, this must not be called
         re-entrantly while a call to any other function (e.g. or1kim_run ())
         is in progress. It is the responsibility of the caller to ensure this
         constraint is met, for example by use of a SystemC mutex.
 
   @return  The time in seconds which the reset took.                        */
/*---------------------------------------------------------------------------*/
double
or1ksim_jtag_reset ()
{
  /* Number of JTAG clock cycles a reset sequence takes */
  const double  JTAG_RESET_CYCLES = 5.0;
 
  jtag_reset ();
 
  return  JTAG_RESET_CYCLES  * (double) config.debug.jtagcycle_ps / 1.0e12;
 
}	/* or1ksim_jtag_reset () */
 
 
/*---------------------------------------------------------------------------*/
/*!Shift a JTAG instruction register
 
   @note Like all the JTAG interface functions, this must not be called
         re-entrantly while a call to any other function (e.g. or1kim_run ())
         is in progress. It is the responsibility of the caller to ensure this
         constraint is met, for example by use of a SystemC mutex.
 
   The register is represented as a vector of bytes, with the byte at offset
   zero being shifted first, and the least significant bit in each byte being
   shifted first. Where the register will not fit in an exact number of bytes,
   the odd bits are in the highest numbered byte, shifted to the low end.
 
   The only JTAG instruction for which we have any significant behavior in
   this model is DEBUG. For completeness the register is parsed and a warning
   given if any register other than DEBUG is shifted.
 
   @param[in,out] jreg      The register to shift in, and the register shifted
                            back out.
   @param[in]     num_bits  The number of bits in the register. Just for
                            sanity check (it should always be 4).
 
   @return  The time in seconds which the shift took.                        */
/*---------------------------------------------------------------------------*/
double
or1ksim_jtag_shift_ir (unsigned char *jreg,
		       int            num_bits)
{
  jtag_shift_ir (jreg, num_bits);
 
  return  (double) num_bits * (double) config.debug.jtagcycle_ps / 1.0e12;
 
}	/* or1ksim_jtag_shift_ir () */
 
 
/*---------------------------------------------------------------------------*/
/*!Shift a JTAG data register
 
   @note Like all the JTAG interface functions, this must not be called
         re-entrantly while a call to any other function (e.g. or1kim_run ())
         is in progress. It is the responsibility of the caller to ensure this
         constraint is met, for example by use of a SystemC mutex.
 
   The register is represented as a vector of bytes, with the byte at offset
   zero being shifted first, and the least significant bit in each byte being
   shifted first. Where the register will not fit in an exact number of bytes,
   the odd bits are in the highest numbered byte, shifted to the low end.
 
   The register is parsed to determine which of the six possible register
   types it could be.
   - MODULE_SELECT
   - WRITE_COMMNAND
   - READ_COMMAND
   - GO_COMMAND
   - WRITE_CONTROL
   - READ_CONTROL
 
   @note In practice READ_COMMAND is not used. However the functionality is
         provided for future compatibility.
 
   @param[in,out] jreg      The register to shift in, and the register shifted
                            back out.
   @param[in]     num_bits  The number of bits in the register. This is
                            essential to prevent bugs where the size of
                            register supplied is incorrect.
 
   @return  The time in seconds which the shift took.                        */
/*---------------------------------------------------------------------------*/
double
or1ksim_jtag_shift_dr (unsigned char *jreg,
		       int            num_bits)
{
  jtag_shift_dr (jreg, num_bits);
 
  return  (double) num_bits * (double) config.debug.jtagcycle_ps / 1.0e12;
 
}	/* or1ksim_jtag_shift_dr () */
 
 
/*---------------------------------------------------------------------------*/
/*!Read a block of memory.
 
   @param[out] buf   Where to put the data.
   @param[in]  addr  The address to read from.
   @param[in]  len   The number of bytes to read.
 
   @return  Number of bytes read, or zero if error.                          */
/*---------------------------------------------------------------------------*/
int
or1ksim_read_mem (unsigned char *buf,
		  unsigned int   addr,
		  int            len)
{
  int             off;			/* Offset into the memory */
 
  /* Fill the buffer with data */
  for (off = 0; off < len; off++)
    {
      /* Check memory area is valid */
      if (NULL == verify_memoryarea (addr + off))
	{
	  /* Fail silently - others can raise any error message. */
	  return  0;
	}
      else
	{
	  /* Get the memory direct - no translation. */
	  buf[off] = eval_direct8 (addr + off, 0, 0);
	}
    }
 
  return  len;
 
}	/* or1ksim_read_mem () */
 
 
/*---------------------------------------------------------------------------*/
/*!Write a block of memory.
 
   @param[in] buf   Where to get the data from.
   @param[in] addr  The address to write to.
   @param[in] len   The number of bytes to write.
 
   @return  Number of bytes written, or zero if error.                       */
/*---------------------------------------------------------------------------*/
int
or1ksim_write_mem (unsigned char *buf,
		   unsigned int   addr,
		   int            len)
{
  int             off;			/* Offset into the memory */
 
  /* Write the bytes to memory */
  for (off = 0; off < len; off++)
    {
      if (NULL == verify_memoryarea (addr + off))
	{
	  /* Fail silently - others can raise any error message. */
	  return  0;
	}
      else
	{
	  /* circumvent the read-only check usually done for mem accesses data
	     is in host order, because that's what set_direct32 needs */
	  set_program8 (addr + off, buf[off]);
	}
    }
 
  return  len;
 
}	/* or1ksim_write_mem () */
 
 
/*---------------------------------------------------------------------------*/
/*!Read a single register
 
   The registers follow the GDB sequence for OR1K: GPR0 through GPR31, PC
   (i.e. SPR NPC) and SR (i.e. SPR SR).
 
   @param[out] buf     Where to put the data.
   @param[in]  regnum  The register to read.
   @param[in]  len     Size of the register in bytes
 
   @return  Size of the register, or zero if error.                          */
/*---------------------------------------------------------------------------*/
int
or1ksim_read_reg (unsigned char *buf,
		  int            regnum,
		  int            len)
{
  unsigned long int *regbuf = (unsigned long *) buf;
 
  if (4 != len)
    {
      return  0;			/* Not 32-bit reg */
    }
 
  /* Get the relevant register */
  if (regnum < MAX_GPRS)
    {
      *regbuf = cpu_state.reg[regnum];
    }
  else if (PPC_REGNUM == regnum)
    {
      *regbuf = cpu_state.sprs[SPR_PPC];
    }
  else if (NPC_REGNUM == regnum)
    {
      *regbuf = cpu_state.pc;
    }
  else if (SR_REGNUM == regnum)
    {
      *regbuf = cpu_state.sprs[SPR_SR];
    }
  else
    {
      /* Silent error response if we don't know the register */
      return  0;
    }
 
  return  len;
 
}	/* or1ksim_read_reg () */
 
 
/*---------------------------------------------------------------------------*/
/*!Write a single register
 
   The registers follow the GDB sequence for OR1K: GPR0 through GPR31, PC
   (i.e. SPR NPC) and SR (i.e. SPR SR). The register is specified as a
   sequence of bytes in target endian order.
 
   Each byte is packed as a pair of hex digits.
 
   @param[in] buf     Where to get the data from.
   @param[in] regnum  The register to write.
   @param[in]  len     Size of the register in bytes
 
   @return  Size of the register, or zero if error.                          */
/*---------------------------------------------------------------------------*/
int
or1ksim_write_reg (unsigned char *buf,
		   int            regnum,
		   int            len)
{
  unsigned long int *regbuf = (unsigned long *) buf;
  unsigned long int  regval = *regbuf;
 
  if (4 != len)
    {
      return  0;			/* Not 32-bit reg */
    }
 
  /* Set the relevant register */
  if (regnum < MAX_GPRS)
    {
      cpu_state.reg[regnum] =regval;
    }
  else if (PPC_REGNUM == regnum)
    {
      cpu_state.sprs[SPR_PPC] = regval;
    }
  else if (NPC_REGNUM == regnum)
    {
      if (cpu_state.pc != regval)
	{
	  cpu_state.pc         = regval;
	  cpu_state.delay_insn = 0;
	  pcnext               = regval + 4;
	}
    }
  else if (SR_REGNUM == regnum)
    {
      cpu_state.sprs[SPR_SR] = regval;
    }
  else
    {
      /* Silent error response if we don't know the register */
      return  0;
    }
 
  return  len;
 
}	/* or1ksim_write_reg () */