sim/example-synacor/interp.c

   1 /* Example synacor simulator.
   2
   3    Copyright (C) 2005-2021 Free Software Foundation, Inc.
   4    Contributed by Mike Frysinger.
   5
   6    This file is part of simulators.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 /* This file contains the main glue logic between the sim core and the target
  22    specific simulator.  Normally this file will be kept small and the target
  23    details will live in other files.
  24
  25    For more specific details on these functions, see the sim/sim.h header
  26    file.  */
  27
  28 /* This must come before any other includes.  */
  29 #include "defs.h"
  30
  31 #include "sim/callback.h"
  32 #include "sim-main.h"
  33 #include "sim-options.h"
  34 \f
  35 /* This function is the main loop.  It should process ticks and decode+execute
  36    a single instruction.
  37
  38    Usually you do not need to change things here.  */
  39
  40 void
  41 sim_engine_run (SIM_DESC sd,
  42                 int next_cpu_nr, /* ignore  */
  43                 int nr_cpus, /* ignore  */
  44                 int siggnal) /* ignore  */
  45 {
  46   SIM_CPU *cpu;
  47
  48   SIM_ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
  49
  50   cpu = STATE_CPU (sd, 0);
  51
  52   while (1)
  53     {
  54       step_once (cpu);
  55       if (sim_events_tick (sd))
  56         sim_events_process (sd);
  57     }
  58 }
  59 \f
  60 /* Initialize the simulator from scratch.  This is called once per lifetime of
  61    the simulation.  Think of it as a processor reset.
  62
  63    Usually all cpu-specific setup is handled in the initialize_cpu callback.
  64    If you want to do cpu-independent stuff, then it should go at the end (see
  65    where memory is initialized).  */
  66
  67 #define DEFAULT_MEM_SIZE (16 * 1024 * 1024)
  68
  69 static void
  70 free_state (SIM_DESC sd)
  71 {
  72   if (STATE_MODULES (sd) != NULL)
  73     sim_module_uninstall (sd);
  74   sim_cpu_free_all (sd);
  75   sim_state_free (sd);
  76 }
  77
  78 SIM_DESC
  79 sim_open (SIM_OPEN_KIND kind, host_callback *callback,
  80           struct bfd *abfd, char * const *argv)
  81 {
  82   char c;
  83   int i;
  84   SIM_DESC sd = sim_state_alloc (kind, callback);
  85
  86   /* Set default options before parsing user options.  */
  87   current_alignment = STRICT_ALIGNMENT;
  88   current_target_byte_order = BFD_ENDIAN_LITTLE;
  89
  90   /* The cpu data is kept in a separately allocated chunk of memory.  */
  91   if (sim_cpu_alloc_all (sd, 1) != SIM_RC_OK)
  92     {
  93       free_state (sd);
  94       return 0;
  95     }
  96
  97   if (sim_pre_argv_init (sd, argv[0]) != SIM_RC_OK)
  98     {
  99       free_state (sd);
 100       return 0;
 101     }
 102
 103   /* XXX: Default to the Virtual environment.  */
 104   if (STATE_ENVIRONMENT (sd) == ALL_ENVIRONMENT)
 105     STATE_ENVIRONMENT (sd) = VIRTUAL_ENVIRONMENT;
 106
 107   /* The parser will print an error message for us, so we silently return.  */
 108   if (sim_parse_args (sd, argv) != SIM_RC_OK)
 109     {
 110       free_state (sd);
 111       return 0;
 112     }
 113
 114   /* Check for/establish the a reference program image.  */
 115   if (sim_analyze_program (sd, STATE_PROG_FILE (sd), abfd) != SIM_RC_OK)
 116     {
 117       free_state (sd);
 118       return 0;
 119     }
 120
 121   /* Establish any remaining configuration options.  */
 122   if (sim_config (sd) != SIM_RC_OK)
 123     {
 124       free_state (sd);
 125       return 0;
 126     }
 127
 128   if (sim_post_argv_init (sd) != SIM_RC_OK)
 129     {
 130       free_state (sd);
 131       return 0;
 132     }
 133
 134   /* CPU specific initialization.  */
 135   for (i = 0; i < MAX_NR_PROCESSORS; ++i)
 136     {
 137       SIM_CPU *cpu = STATE_CPU (sd, i);
 138
 139       initialize_cpu (sd, cpu);
 140     }
 141
 142   /* Allocate external memory if none specified by user.
 143      Use address 4 here in case the user wanted address 0 unmapped.  */
 144   if (sim_core_read_buffer (sd, NULL, read_map, &c, 4, 1) == 0)
 145     sim_do_commandf (sd, "memory-size %#x", DEFAULT_MEM_SIZE);
 146
 147   return sd;
 148 }
 149 \f
 150 /* Prepare to run a program that has already been loaded into memory.
 151
 152    Usually you do not need to change things here.  */
 153
 154 SIM_RC
 155 sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
 156                      char * const *argv, char * const *env)
 157 {
 158   SIM_CPU *cpu = STATE_CPU (sd, 0);
 159   host_callback *cb = STATE_CALLBACK (sd);
 160   sim_cia addr;
 161
 162   /* Set the PC.  */
 163   if (abfd != NULL)
 164     addr = bfd_get_start_address (abfd);
 165   else
 166     addr = 0;
 167   sim_pc_set (cpu, addr);
 168
 169   /* Standalone mode (i.e. `run`) will take care of the argv for us in
 170      sim_open() -> sim_parse_args().  But in debug mode (i.e. 'target sim'
 171      with `gdb`), we need to handle it because the user can change the
 172      argv on the fly via gdb's 'run'.  */
 173   if (STATE_PROG_ARGV (sd) != argv)
 174     {
 175       freeargv (STATE_PROG_ARGV (sd));
 176       STATE_PROG_ARGV (sd) = dupargv (argv);
 177     }
 178
 179   if (STATE_PROG_ENVP (sd) != env)
 180     {
 181       freeargv (STATE_PROG_ENVP (sd));
 182       STATE_PROG_ENVP (sd) = dupargv (env);
 183     }
 184
 185   cb->argv = STATE_PROG_ARGV (sd);
 186   cb->envp = STATE_PROG_ENVP (sd);
 187
 188   return SIM_RC_OK;
 189 }