sim/igen/gen-semantics.c

   1 /* The IGEN simulator generator for GDB, the GNU Debugger.
   2
   3    Copyright 2002-2023 Free Software Foundation, Inc.
   4
   5    Contributed by Andrew Cagney.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22
  23
  24 #include "misc.h"
  25 #include "lf.h"
  26 #include "table.h"
  27 #include "filter.h"
  28 #include "igen.h"
  29
  30 #include "ld-insn.h"
  31 #include "ld-decode.h"
  32
  33 #include "gen.h"
  34
  35 #include "gen-semantics.h"
  36 #include "gen-icache.h"
  37 #include "gen-idecode.h"
  38
  39
  40 static void
  41 print_semantic_function_header (lf *file,
  42                                 const char *basename,
  43                                 const char *format_name,
  44                                 const opcode_bits *expanded_bits,
  45                                 int is_function_definition,
  46                                 int nr_prefetched_words)
  47 {
  48   int indent;
  49   lf_printf (file, "\n");
  50   lf_print__function_type_function (file, print_semantic_function_type,
  51                                     "EXTERN_SEMANTICS",
  52                                     (is_function_definition ? "\n" : " "));
  53   indent = print_function_name (file,
  54                                 basename,
  55                                 format_name,
  56                                 NULL,
  57                                 expanded_bits,
  58                                 function_name_prefix_semantics);
  59   if (is_function_definition)
  60     {
  61       indent += lf_printf (file, " ");
  62       lf_indent (file, +indent);
  63     }
  64   else
  65     {
  66       lf_printf (file, "\n");
  67     }
  68   lf_printf (file, "(");
  69   lf_indent (file, +1);
  70   print_semantic_function_formal (file, nr_prefetched_words);
  71   lf_indent (file, -1);
  72   lf_printf (file, ")");
  73   if (is_function_definition)
  74     {
  75       lf_indent (file, -indent);
  76     }
  77   else
  78     {
  79       lf_printf (file, ";");
  80     }
  81   lf_printf (file, "\n");
  82 }
  83
  84 void
  85 print_semantic_declaration (lf *file,
  86                             const insn_entry *insn,
  87                             const opcode_bits *expanded_bits,
  88                             const insn_opcodes *opcodes,
  89                             int nr_prefetched_words)
  90 {
  91   print_semantic_function_header (file,
  92                                   insn->name,
  93                                   insn->format_name,
  94                                   expanded_bits,
  95                                   0 /* is not function definition */ ,
  96                                   nr_prefetched_words);
  97 }
  98 \f
  99
 100
 101 /* generate the semantics.c file */
 102
 103
 104 void
 105 print_idecode_invalid (lf *file, const char *result, invalid_type type)
 106 {
 107   const char *name;
 108   switch (type)
 109     {
 110     default:
 111       name = "unknown";
 112       break;
 113     case invalid_illegal:
 114       name = "illegal";
 115       break;
 116     case invalid_fp_unavailable:
 117       name = "fp_unavailable";
 118       break;
 119     case invalid_wrong_slot:
 120       name = "wrong_slot";
 121       break;
 122     }
 123   if (options.gen.code == generate_jumps)
 124     {
 125       lf_printf (file, "goto %s_%s;\n",
 126                  (options.gen.icache ? "icache" : "semantic"), name);
 127     }
 128   else if (options.gen.icache)
 129     {
 130       lf_printf (file, "%s %sicache_%s (", result,
 131                  options.module.global.prefix.l, name);
 132       print_icache_function_actual (file, 0);
 133       lf_printf (file, ");\n");
 134     }
 135   else
 136     {
 137       lf_printf (file, "%s %ssemantic_%s (", result,
 138                  options.module.global.prefix.l, name);
 139       print_semantic_function_actual (file, 0);
 140       lf_printf (file, ");\n");
 141     }
 142 }
 143
 144
 145 void
 146 print_semantic_body (lf *file,
 147                      const insn_entry *instruction,
 148                      const opcode_bits *expanded_bits,
 149                      const insn_opcodes *opcodes)
 150 {
 151   /* validate the instruction, if a cache this has already been done */
 152   if (!options.gen.icache)
 153     {
 154       print_idecode_validate (file, instruction, opcodes);
 155     }
 156
 157   print_itrace (file, instruction, 0 /*put_value_in_cache */ );
 158
 159   /* generate the instruction profile call - this is delayed until
 160      after the instruction has been verified.  The count macro
 161      generated is prefixed by ITABLE_PREFIX */
 162   {
 163     lf_printf (file, "\n");
 164     lf_indent_suppress (file);
 165     lf_printf (file, "#if defined (%sPROFILE_COUNT_INSN)\n",
 166                options.module.itable.prefix.u);
 167     lf_printf (file, "%sPROFILE_COUNT_INSN (CPU, CIA, MY_INDEX);\n",
 168                options.module.itable.prefix.u);
 169     lf_indent_suppress (file);
 170     lf_printf (file, "#endif\n");
 171   }
 172
 173   /* generate the model call - this is delayed until after the
 174      instruction has been verified */
 175   {
 176     lf_printf (file, "\n");
 177     lf_indent_suppress (file);
 178     lf_printf (file, "#if defined (WITH_MON)\n");
 179     lf_printf (file, "/* monitoring: */\n");
 180     lf_printf (file, "if (WITH_MON & MONITOR_INSTRUCTION_ISSUE)\n");
 181     lf_printf (file, "  mon_issue (");
 182     print_function_name (file,
 183                          instruction->name,
 184                          instruction->format_name,
 185                          NULL, NULL, function_name_prefix_itable);
 186     lf_printf (file, ", cpu, cia);\n");
 187     lf_indent_suppress (file);
 188     lf_printf (file, "#endif\n");
 189     lf_printf (file, "\n");
 190   }
 191
 192   /* determine the new instruction address */
 193   {
 194     lf_printf (file, "/* keep the next instruction address handy */\n");
 195     if (options.gen.nia == nia_is_invalid)
 196       {
 197         lf_printf (file, "nia = %sINVALID_INSTRUCTION_ADDRESS;\n",
 198                    options.module.global.prefix.u);
 199       }
 200     else
 201       {
 202         int nr_immeds = instruction->nr_words - 1;
 203         if (options.gen.delayed_branch)
 204           {
 205             if (nr_immeds > 0)
 206               {
 207                 lf_printf (file, "cia.dp += %d * %d; %s\n",
 208                            options.insn_bit_size / 8, nr_immeds,
 209                            "/* skip dp immeds */");
 210               }
 211             lf_printf (file, "nia.ip = cia.dp; %s\n",
 212                        "/* instruction pointer */");
 213             lf_printf (file, "nia.dp = cia.dp + %d; %s\n",
 214                        options.insn_bit_size / 8,
 215                        "/* delayed-slot pointer */");
 216           }
 217         else
 218           {
 219             if (nr_immeds > 0)
 220               {
 221                 lf_printf (file, "nia = cia + %d * (%d + 1); %s\n",
 222                            options.insn_bit_size / 8, nr_immeds,
 223                            "/* skip immeds as well */");
 224
 225               }
 226             else
 227               {
 228                 lf_printf (file, "nia = cia + %d;\n",
 229                            options.insn_bit_size / 8);
 230               }
 231           }
 232       }
 233   }
 234
 235   /* if conditional, generate code to verify that the instruction
 236      should be issued */
 237   if (filter_is_member (instruction->options, "c")
 238       || options.gen.conditional_issue)
 239     {
 240       lf_printf (file, "\n");
 241       lf_printf (file, "/* execute only if conditional passes */\n");
 242       lf_printf (file, "if (IS_CONDITION_OK)\n");
 243       lf_printf (file, "  {\n");
 244       lf_indent (file, +4);
 245       /* FIXME - need to log a conditional failure */
 246     }
 247
 248   /* Architecture expects a REG to be zero.  Instead of having to
 249      check every read to see if it is refering to that REG just zap it
 250      at the start of every instruction */
 251   if (options.gen.zero_reg)
 252     {
 253       lf_printf (file, "\n");
 254       lf_printf (file, "/* Architecture expects REG to be zero */\n");
 255       lf_printf (file, "GPR_CLEAR(%d);\n", options.gen.zero_reg_nr);
 256     }
 257
 258   /* generate the code (or at least something */
 259   lf_printf (file, "\n");
 260   lf_printf (file, "/* semantics: */\n");
 261   if (instruction->code != NULL)
 262     {
 263       /* true code */
 264       lf_printf (file, "{\n");
 265       lf_indent (file, +2);
 266       lf_print__line_ref (file, instruction->code->line);
 267       table_print_code (file, instruction->code);
 268       lf_indent (file, -2);
 269       lf_printf (file, "}\n");
 270       lf_print__internal_ref (file);
 271     }
 272   else if (filter_is_member (instruction->options, "nop"))
 273     {
 274       lf_print__internal_ref (file);
 275     }
 276   else
 277     {
 278       const char *prefix = "sim_engine_abort (";
 279       int indent = strlen (prefix);
 280       /* abort so it is implemented now */
 281       lf_print__line_ref (file, instruction->line);
 282       lf_printf (file, "%sSD, CPU, cia, \\\n", prefix);
 283       lf_indent (file, +indent);
 284       lf_printf (file, "\"%s:%d:0x%%08lx:%%s unimplemented\\n\", \\\n",
 285                  filter_filename (instruction->line->file_name),
 286                  instruction->line->line_nr);
 287       lf_printf (file, "(long) CIA, \\\n");
 288       lf_printf (file, "%sitable[MY_INDEX].name);\n",
 289                  options.module.itable.prefix.l);
 290       lf_indent (file, -indent);
 291       lf_print__internal_ref (file);
 292     }
 293
 294   /* Close off the conditional execution */
 295   if (filter_is_member (instruction->options, "c")
 296       || options.gen.conditional_issue)
 297     {
 298       lf_indent (file, -4);
 299       lf_printf (file, "  }\n");
 300     }
 301 }
 302
 303 static void
 304 print_c_semantic (lf *file,
 305                   const insn_entry *instruction,
 306                   const opcode_bits *expanded_bits,
 307                   const insn_opcodes *opcodes,
 308                   cache_entry *cache_rules,
 309                   int nr_prefetched_words)
 310 {
 311
 312   lf_printf (file, "{\n");
 313   lf_indent (file, +2);
 314
 315   print_my_defines (file,
 316                     instruction->name,
 317                     instruction->format_name, expanded_bits);
 318   lf_printf (file, "\n");
 319   print_icache_body (file,
 320                      instruction,
 321                      expanded_bits,
 322                      cache_rules,
 323                      (options.gen.direct_access
 324                       ? define_variables
 325                       : declare_variables),
 326                      (options.gen.icache
 327                       ? get_values_from_icache
 328                       : do_not_use_icache), nr_prefetched_words);
 329
 330   lf_printf (file, "%sinstruction_address nia;\n",
 331              options.module.global.prefix.l);
 332   print_semantic_body (file, instruction, expanded_bits, opcodes);
 333   lf_printf (file, "return nia;\n");
 334
 335   /* generate something to clean up any #defines created for the cache */
 336   if (options.gen.direct_access)
 337     {
 338       print_icache_body (file,
 339                          instruction,
 340                          expanded_bits,
 341                          cache_rules,
 342                          undef_variables,
 343                          (options.gen.icache
 344                           ? get_values_from_icache
 345                           : do_not_use_icache), nr_prefetched_words);
 346     }
 347
 348   lf_indent (file, -2);
 349   lf_printf (file, "}\n");
 350 }
 351
 352 static void
 353 print_c_semantic_function (lf *file,
 354                            const insn_entry *instruction,
 355                            const opcode_bits *expanded_bits,
 356                            const insn_opcodes *opcodes,
 357                            cache_entry *cache_rules,
 358                            int nr_prefetched_words)
 359 {
 360   /* build the semantic routine to execute the instruction */
 361   print_semantic_function_header (file,
 362                                   instruction->name,
 363                                   instruction->format_name,
 364                                   expanded_bits,
 365                                   1 /*is-function-definition */ ,
 366                                   nr_prefetched_words);
 367   print_c_semantic (file,
 368                     instruction,
 369                     expanded_bits, opcodes, cache_rules, nr_prefetched_words);
 370 }
 371
 372 void
 373 print_semantic_definition (lf *file,
 374                            const insn_entry *insn,
 375                            const opcode_bits *expanded_bits,
 376                            const insn_opcodes *opcodes,
 377                            cache_entry *cache_rules,
 378                            int nr_prefetched_words)
 379 {
 380   print_c_semantic_function (file,
 381                              insn,
 382                              expanded_bits,
 383                              opcodes, cache_rules, nr_prefetched_words);
 384 }