PExpr.h

   1 #ifndef __PExpr_H
   2 #define __PExpr_H
   3 /*
   4  * Copyright (c) 1998-2000 Stephen Williams <steve@icarus.com>
   5  *
   6  *    This source code is free software; you can redistribute it
   7  *    and/or modify it in source code form under the terms of the GNU
   8  *    General Public License as published by the Free Software
   9  *    Foundation; either version 2 of the License, or (at your option)
  10  *    any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  20  */
  21
  22 # include  <string>
  23 # include  <vector>
  24 # include  "netlist.h"
  25 # include  "verinum.h"
  26 # include  "LineInfo.h"
  27 # include  "pform_types.h"
  28
  29 class Design;
  30 class Module;
  31 class NetNet;
  32 class NetExpr;
  33 class NetScope;
  34
  35 /*
  36  * The PExpr class hierarchy supports the description of
  37  * expressions. The parser can generate expression objects from the
  38  * source, possibly reducing things that it knows how to reduce.
  39  *
  40  * The elaborate_net method is used by structural elaboration to build
  41  * up a netlist interpretation of the expression.
  42  */
  43
  44 class PExpr : public LineInfo {
  45
  46     public:
  47       PExpr();
  48       virtual ~PExpr();
  49
  50       virtual void dump(ostream&) const;
  51
  52         // This method tests the width that the expression wants to
  53         // be. It is used by elaboration of assignments to figure out
  54         // the width of the expression.
  55         //
  56         // The "min" is the width of the local context, so it the
  57         // minimum width that this function should return. Initially
  58         // this is the same as the lval width.
  59         //
  60         // The "lval" is the width of the destination where this
  61         // result is going to go. This can be used to constrain the
  62         // amount that an expression can reasonably expand. For
  63         // example, there is no point expanding an addition to beyond
  64         // the lval. This extra bit of information allows the
  65         // expression to optimize itself a bit. If the lval==0, then
  66         // the subexpression should not make l-value related
  67         // optimizations.
  68         //
  69         // The unsigned_flag is set to true if the expression is
  70         // unsized and therefore expandable. This happens if a
  71         // sub-expression is an unsized literal. Some expressions make
  72         // special use of that.
  73       virtual unsigned test_width(Design*des, NetScope*scope,
  74                                   unsigned min, unsigned lval,
  75                                   bool&unsized_flag) const;
  76
  77         // Procedural elaboration of the expression. The expr_width is
  78         // the width of the context of the expression (i.e. the
  79         // l-value width of an assignment),
  80         //
  81         // ... or -1 if the expression is self-determined. or
  82         // ... or -2 if the expression is losslessly
  83         // self-determined. This can happen in situations where the
  84         // result is going to a pseudo-infinitely wide context.
  85         //
  86         // The sys_task_arg flag is true if expressions are allowed to
  87         // be incomplete.
  88       virtual NetExpr*elaborate_expr(Design*des, NetScope*scope,
  89                                      int expr_width, bool sys_task_arg) const;
  90
  91         // Elaborate expressions that are the r-value of parameter
  92         // assignments. This elaboration follows the restrictions of
  93         // constant expressions and supports later overriding and
  94         // evaluation of parameters.
  95       virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
  96
  97         // This method elaborate the expression as gates, for use in a
  98         // continuous assign or other wholly structural context.
  99       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 100                                     unsigned lwidth,
 101                                     const NetExpr* rise,
 102                                     const NetExpr* fall,
 103                                     const NetExpr* decay,
 104                                     Link::strength_t drive0 =Link::STRONG,
 105                                     Link::strength_t drive1 =Link::STRONG)
 106             const;
 107
 108         // This method elaborates the expression as gates, but
 109         // restricted for use as l-values of continuous assignments.
 110       virtual NetNet* elaborate_lnet(Design*des, NetScope*scope,
 111                                      bool implicit_net_ok =false) const;
 112
 113         // This is similar to elaborate_lnet, except that the
 114         // expression is evaluated to be bi-directional. This is
 115         // useful for arguments to inout ports of module instances and
 116         // ports of tran primitives.
 117       virtual NetNet* elaborate_bi_net(Design*des, NetScope*scope) const;
 118
 119         // Expressions that can be in the l-value of procedural
 120         // assignments can be elaborated with this method. If the
 121         // is_force flag is true, then the set of valid l-value types
 122         // is slightly modified to accomodate the Verilog force
 123         // statement
 124       virtual NetAssign_* elaborate_lval(Design*des,
 125                                          NetScope*scope,
 126                                          bool is_force) const;
 127
 128         // This attempts to evaluate a constant expression, and return
 129         // a verinum as a result. If the expression cannot be
 130         // evaluated, return 0.
 131       virtual verinum* eval_const(Design*des, NetScope*sc) const;
 132
 133         // This method returns true if that expression is the same as
 134         // this expression. This method is used for comparing
 135         // expressions that must be structurally "identical".
 136       virtual bool is_the_same(const PExpr*that) const;
 137
 138         // Return true if this expression is a valid constant
 139         // expression. the Module pointer is needed to find parameter
 140         // identifiers and any other module specific interpretations
 141         // of expressions.
 142       virtual bool is_constant(Module*) const;
 143
 144     private: // not implemented
 145       PExpr(const PExpr&);
 146       PExpr& operator= (const PExpr&);
 147 };
 148
 149 ostream& operator << (ostream&, const PExpr&);
 150
 151 class PEConcat : public PExpr {
 152
 153     public:
 154       PEConcat(const svector<PExpr*>&p, PExpr*r =0);
 155       ~PEConcat();
 156
 157       virtual verinum* eval_const(Design*des, NetScope*sc) const;
 158       virtual void dump(ostream&) const;
 159
 160       virtual NetNet* elaborate_lnet(Design*des, NetScope*scope,
 161                                      bool implicit_net_ok =false) const;
 162       virtual NetNet* elaborate_bi_net(Design*des, NetScope*scope) const;
 163       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 164                                     unsigned width,
 165                                     const NetExpr* rise,
 166                                     const NetExpr* fall,
 167                                     const NetExpr* decay,
 168                                     Link::strength_t drive0,
 169                                     Link::strength_t drive1) const;
 170       virtual NetExpr*elaborate_expr(Design*des, NetScope*,
 171                                      int expr_width, bool sys_task_arg) const;
 172       virtual NetEConcat*elaborate_pexpr(Design*des, NetScope*) const;
 173       virtual NetAssign_* elaborate_lval(Design*des,
 174                                          NetScope*scope,
 175                                          bool is_force) const;
 176       virtual bool is_constant(Module*) const;
 177
 178     private:
 179       NetNet* elaborate_lnet_common_(Design*des, NetScope*scope,
 180                                      bool implicit_net_ok,
 181                                      bool bidirectional_flag) const;
 182     private:
 183       svector<PExpr*>parms_;
 184       PExpr*repeat_;
 185 };
 186
 187 /*
 188  * Event expressions are expressions that can be combined with the
 189  * event "or" operator. These include "posedge foo" and similar, and
 190  * also include named events. "edge" events are associated with an
 191  * expression, whereas named events simply have a name, which
 192  * represents an event variable.
 193  */
 194 class PEEvent : public PExpr {
 195
 196     public:
 197       enum edge_t {ANYEDGE, POSEDGE, NEGEDGE, POSITIVE};
 198
 199         // Use this constructor to create events based on edges or levels.
 200       PEEvent(edge_t t, PExpr*e);
 201
 202       ~PEEvent();
 203
 204       edge_t type() const;
 205       PExpr* expr() const;
 206
 207       virtual void dump(ostream&) const;
 208
 209     private:
 210       edge_t type_;
 211       PExpr *expr_;
 212 };
 213
 214 /*
 215  * This holds a floating point constant in the source.
 216  */
 217 class PEFNumber : public PExpr {
 218
 219     public:
 220       explicit PEFNumber(verireal*vp);
 221       ~PEFNumber();
 222
 223       const verireal& value() const;
 224
 225         /* The eval_const method as applied to a floating point number
 226            gets the *integer* value of the number. This accounts for
 227            any rounding that is needed to get the value. */
 228       virtual verinum* eval_const(Design*des, NetScope*sc) const;
 229
 230         /* A PEFNumber is a constant, so this returns true. */
 231       virtual bool is_constant(Module*) const;
 232
 233       virtual NetExpr*elaborate_expr(Design*des, NetScope*,
 234                                      int expr_width, bool sys_task_arg) const;
 235       virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
 236
 237       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 238                                     unsigned lwidth,
 239                                     const NetExpr* rise,
 240                                     const NetExpr* fall,
 241                                     const NetExpr* decay,
 242                                     Link::strength_t drive0,
 243                                     Link::strength_t drive1) const;
 244
 245       virtual void dump(ostream&) const;
 246
 247     private:
 248       verireal*value_;
 249 };
 250
 251 class PEIdent : public PExpr {
 252
 253     public:
 254       explicit PEIdent(perm_string);
 255       explicit PEIdent(const pform_name_t&);
 256       ~PEIdent();
 257
 258         // Add another name to the string of heirarchy that is the
 259         // current identifier.
 260       void append_name(perm_string);
 261
 262       virtual void dump(ostream&) const;
 263       virtual unsigned test_width(Design*des, NetScope*scope,
 264                                   unsigned min, unsigned lval,
 265                                   bool&unsized_flag) const;
 266
 267         // Identifiers are allowed (with restrictions) is assign l-values.
 268       virtual NetNet* elaborate_lnet(Design*des, NetScope*scope,
 269                                      bool implicit_net_ok =false) const;
 270
 271       virtual NetNet* elaborate_bi_net(Design*des, NetScope*scope) const;
 272
 273         // Identifiers are also allowed as procedural assignment l-values.
 274       virtual NetAssign_* elaborate_lval(Design*des,
 275                                          NetScope*scope,
 276                                          bool is_force) const;
 277
 278         // Structural r-values are OK.
 279       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 280                                     unsigned lwidth,
 281                                     const NetExpr* rise,
 282                                     const NetExpr* fall,
 283                                     const NetExpr* decay,
 284                                     Link::strength_t drive0,
 285                                     Link::strength_t drive1) const;
 286
 287       virtual NetExpr*elaborate_expr(Design*des, NetScope*,
 288                                      int expr_width, bool sys_task_arg) const;
 289       virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
 290
 291         // Elaborate the PEIdent as a port to a module. This method
 292         // only applies to Ident expressions.
 293       NetNet* elaborate_port(Design*des, NetScope*sc) const;
 294
 295       virtual bool is_constant(Module*) const;
 296       verinum* eval_const(Design*des, NetScope*sc) const;
 297
 298       const pform_name_t& path() const { return path_; }
 299
 300     private:
 301       pform_name_t path_;
 302
 303     private:
 304         // Common functions to calculate parts of part/bit selects.
 305       bool calculate_parts_(Design*, NetScope*, long&msb, long&lsb) const;
 306       bool calculate_up_do_width_(Design*, NetScope*, unsigned long&wid) const;
 307
 308     private:
 309       NetAssign_*elaborate_lval_net_word_(Design*, NetScope*, NetNet*) const;
 310       bool elaborate_lval_net_part_(Design*, NetScope*, NetAssign_*) const;
 311       bool elaborate_lval_net_idx_(Design*, NetScope*, NetAssign_*,
 312                                    index_component_t::ctype_t) const;
 313
 314     private:
 315       NetExpr*elaborate_expr_param(Design*des,
 316                                    NetScope*scope,
 317                                    const NetExpr*par,
 318                                    NetScope*found,
 319                                    const NetExpr*par_msb,
 320                                    const NetExpr*par_lsb) const;
 321       NetExpr*elaborate_expr_net(Design*des,
 322                                  NetScope*scope,
 323                                  NetNet*net,
 324                                  NetScope*found,
 325                                  bool sys_task_arg) const;
 326       NetExpr*elaborate_expr_net_word_(Design*des,
 327                                        NetScope*scope,
 328                                        NetNet*net,
 329                                        NetScope*found,
 330                                        bool sys_task_arg) const;
 331       NetExpr*elaborate_expr_net_part_(Design*des,
 332                                    NetScope*scope,
 333                                    NetESignal*net,
 334                                    NetScope*found) const;
 335       NetExpr*elaborate_expr_net_idx_up_(Design*des,
 336                                    NetScope*scope,
 337                                    NetESignal*net,
 338                                    NetScope*found) const;
 339       NetExpr*elaborate_expr_net_idx_do_(Design*des,
 340                                    NetScope*scope,
 341                                    NetESignal*net,
 342                                    NetScope*found) const;
 343       NetExpr*elaborate_expr_net_bit_(Design*des,
 344                                    NetScope*scope,
 345                                    NetESignal*net,
 346                                    NetScope*found) const;
 347
 348     public:
 349
 350       NetNet* elaborate_net_array_(Design*des, NetScope*scope,
 351                                    NetNet*sig, unsigned lwidth,
 352                                    const NetExpr* rise,
 353                                    const NetExpr* fall,
 354                                    const NetExpr* decay,
 355                                    Link::strength_t drive0,
 356                                    Link::strength_t drive1) const;
 357
 358       NetNet* elaborate_net_net_(Design*des, NetScope*scope,
 359                                  NetNet*sig, unsigned lwidth,
 360                                  const NetExpr* rise,
 361                                  const NetExpr* fall,
 362                                  const NetExpr* decay,
 363                                  Link::strength_t drive0,
 364                                  Link::strength_t drive1) const;
 365       NetNet* elaborate_net_net_idx_up_(Design*des, NetScope*scope,
 366                                         NetNet*sig, unsigned lwidth,
 367                                         const NetExpr* rise,
 368                                         const NetExpr* fall,
 369                                         const NetExpr* decay,
 370                                         Link::strength_t drive0,
 371                                         Link::strength_t drive1) const;
 372       NetNet* elaborate_net_bitmux_(Design*des, NetScope*scope,
 373                                     NetNet*sig,
 374                                     const NetExpr* rise,
 375                                     const NetExpr* fall,
 376                                     const NetExpr* decay,
 377                                     Link::strength_t drive0,
 378                                     Link::strength_t drive1) const;
 379
 380     private:
 381       NetNet* elaborate_lnet_common_(Design*des, NetScope*scope,
 382                                      bool implicit_net_ok,
 383                                      bool bidirectional_flag) const;
 384
 385       NetNet*make_implicit_net_(Design*des, NetScope*scope) const;
 386
 387       bool eval_part_select_(Design*des, NetScope*scope, NetNet*sig,
 388                              unsigned&midx, unsigned&lidx) const;
 389       NetNet*process_select_(Design*des, NetScope*scope, NetNet*sig) const;
 390
 391 };
 392
 393 class PENumber : public PExpr {
 394
 395     public:
 396       explicit PENumber(verinum*vp);
 397       ~PENumber();
 398
 399       const verinum& value() const;
 400
 401       virtual void dump(ostream&) const;
 402       virtual unsigned test_width(Design*des, NetScope*scope,
 403                                   unsigned min, unsigned lval,
 404                                   bool&unsized_flag) const;
 405
 406       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 407                                     unsigned lwidth,
 408                                     const NetExpr* rise,
 409                                     const NetExpr* fall,
 410                                     const NetExpr* decay,
 411                                     Link::strength_t drive0,
 412                                     Link::strength_t drive1) const;
 413       virtual NetEConst*elaborate_expr(Design*des, NetScope*,
 414                                        int expr_width, bool) const;
 415       virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
 416       virtual NetAssign_* elaborate_lval(Design*des,
 417                                          NetScope*scope,
 418                                          bool is_force) const;
 419
 420       virtual verinum* eval_const(Design*des, NetScope*sc) const;
 421
 422       virtual bool is_the_same(const PExpr*that) const;
 423       virtual bool is_constant(Module*) const;
 424
 425     private:
 426       verinum*const value_;
 427 };
 428
 429 /*
 430  * This represents a string constant in an expression.
 431  *
 432  * The s parameter to the PEString constructor is a C string that this
 433  * class instance will take for its own. The caller should not delete
 434  * the string, the destructor will do it.
 435  */
 436 class PEString : public PExpr {
 437
 438     public:
 439       explicit PEString(char*s);
 440       ~PEString();
 441
 442       string value() const;
 443       virtual void dump(ostream&) const;
 444
 445       virtual unsigned test_width(Design*des, NetScope*scope,
 446                                   unsigned min, unsigned lval,
 447                                   bool&unsized_flag) const;
 448
 449       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 450                                     unsigned width,
 451                                     const NetExpr* rise,
 452                                     const NetExpr* fall,
 453                                     const NetExpr* decay,
 454                                     Link::strength_t drive0,
 455                                     Link::strength_t drive1) const;
 456       virtual NetEConst*elaborate_expr(Design*des, NetScope*,
 457                                        int expr_width, bool) const;
 458       virtual NetEConst*elaborate_pexpr(Design*des, NetScope*sc) const;
 459       verinum* eval_const(Design*, NetScope*) const;
 460
 461       virtual bool is_constant(Module*) const;
 462
 463     private:
 464       char*text_;
 465 };
 466
 467 class PEUnary : public PExpr {
 468
 469     public:
 470       explicit PEUnary(char op, PExpr*ex);
 471       ~PEUnary();
 472
 473       virtual void dump(ostream&out) const;
 474
 475       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 476                                     unsigned width,
 477                                     const NetExpr* rise,
 478                                     const NetExpr* fall,
 479                                     const NetExpr* decay,
 480                                     Link::strength_t drive0,
 481                                     Link::strength_t drive1) const;
 482       virtual NetExpr*elaborate_expr(Design*des, NetScope*,
 483                                      int expr_width, bool sys_task_arg) const;
 484       virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
 485       virtual verinum* eval_const(Design*des, NetScope*sc) const;
 486
 487       virtual bool is_constant(Module*) const;
 488
 489     private:
 490       char op_;
 491       PExpr*expr_;
 492 };
 493
 494 class PEBinary : public PExpr {
 495
 496     public:
 497       explicit PEBinary(char op, PExpr*l, PExpr*r);
 498       ~PEBinary();
 499
 500       virtual bool is_constant(Module*) const;
 501
 502       virtual void dump(ostream&out) const;
 503
 504       virtual unsigned test_width(Design*des, NetScope*scope,
 505                                   unsigned min, unsigned lval,
 506                                   bool&unsized_flag) const;
 507
 508       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 509                                     unsigned width,
 510                                     const NetExpr* rise,
 511                                     const NetExpr* fall,
 512                                     const NetExpr* decay,
 513                                     Link::strength_t drive0,
 514                                     Link::strength_t drive1) const;
 515       virtual NetEBinary*elaborate_expr(Design*des, NetScope*,
 516                                         int expr_width, bool sys_task_arg) const;
 517       virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
 518       virtual verinum* eval_const(Design*des, NetScope*sc) const;
 519
 520     protected:
 521       char op_;
 522       PExpr*left_;
 523       PExpr*right_;
 524
 525       NetEBinary*elaborate_expr_base_(Design*, NetExpr*lp, NetExpr*rp, int use_wid) const;
 526       NetEBinary*elaborate_eval_expr_base_(Design*, NetExpr*lp, NetExpr*rp, int use_wid) const;
 527
 528       static void surpress_operand_sign_if_needed_(NetExpr*lp, NetExpr*rp);
 529
 530     private:
 531       NetNet* elaborate_net_add_(Design*des, NetScope*scope,
 532                                  unsigned lwidth,
 533                                  const NetExpr* rise,
 534                                  const NetExpr* fall,
 535                                  const NetExpr* decay) const;
 536       NetNet* elaborate_net_bit_(Design*des, NetScope*scope,
 537                                  unsigned lwidth,
 538                                  const NetExpr* rise,
 539                                  const NetExpr* fall,
 540                                  const NetExpr* decay) const;
 541       NetNet* elaborate_net_cmp_(Design*des, NetScope*scope,
 542                                  unsigned lwidth,
 543                                  const NetExpr* rise,
 544                                  const NetExpr* fall,
 545                                  const NetExpr* decay) const;
 546       NetNet* elaborate_net_div_(Design*des, NetScope*scope,
 547                                  unsigned lwidth,
 548                                  const NetExpr* rise,
 549                                  const NetExpr* fall,
 550                                  const NetExpr* decay) const;
 551       NetNet* elaborate_net_mod_(Design*des, NetScope*scope,
 552                                  unsigned lwidth,
 553                                  const NetExpr* rise,
 554                                  const NetExpr* fall,
 555                                  const NetExpr* decay) const;
 556       NetNet* elaborate_net_log_(Design*des, NetScope*scope,
 557                                  unsigned lwidth,
 558                                  const NetExpr* rise,
 559                                  const NetExpr* fall,
 560                                  const NetExpr* decay) const;
 561       NetNet* elaborate_net_mul_(Design*des, NetScope*scope,
 562                                  unsigned lwidth,
 563                                  const NetExpr* rise,
 564                                  const NetExpr* fall,
 565                                  const NetExpr* decay) const;
 566       NetNet* elaborate_net_shift_(Design*des, NetScope*scope,
 567                                    unsigned lwidth,
 568                                    const NetExpr* rise,
 569                                    const NetExpr* fall,
 570                                    const NetExpr* decay) const;
 571 };
 572
 573 /*
 574  * Here are a few specilized classes for handling specific binary
 575  * operators.
 576  */
 577 class PEBComp  : public PEBinary {
 578
 579     public:
 580       explicit PEBComp(char op, PExpr*l, PExpr*r);
 581       ~PEBComp();
 582
 583       virtual unsigned test_width(Design*des, NetScope*scope,
 584                                   unsigned min, unsigned lval,
 585                                   bool&flag) const;
 586
 587       NetEBinary* elaborate_expr(Design*des, NetScope*scope,
 588                                  int expr_width, bool sys_task_arg) const;
 589 };
 590
 591 class PEBShift  : public PEBinary {
 592
 593     public:
 594       explicit PEBShift(char op, PExpr*l, PExpr*r);
 595       ~PEBShift();
 596
 597       virtual unsigned test_width(Design*des, NetScope*scope,
 598                                   unsigned min, unsigned lval, bool&flag) const;
 599 };
 600
 601 /*
 602  * This class supports the ternary (?:) operator. The operator takes
 603  * three expressions, the test, the true result and the false result.
 604  */
 605 class PETernary : public PExpr {
 606
 607     public:
 608       explicit PETernary(PExpr*e, PExpr*t, PExpr*f);
 609       ~PETernary();
 610
 611       virtual bool is_constant(Module*) const;
 612
 613       virtual void dump(ostream&out) const;
 614       virtual unsigned test_width(Design*des, NetScope*scope,
 615                                   unsigned min, unsigned lval,
 616                                   bool&unsized_flag) const;
 617
 618       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 619                                     unsigned width,
 620                                     const NetExpr* rise,
 621                                     const NetExpr* fall,
 622                                     const NetExpr* decay,
 623                                     Link::strength_t drive0,
 624                                     Link::strength_t drive1) const;
 625       virtual NetETernary*elaborate_expr(Design*des, NetScope*,
 626                                          int expr_width, bool sys_task_arg) const;
 627       virtual NetETernary*elaborate_pexpr(Design*des, NetScope*sc) const;
 628       virtual verinum* eval_const(Design*des, NetScope*sc) const;
 629
 630     private:
 631       PExpr*expr_;
 632       PExpr*tru_;
 633       PExpr*fal_;
 634 };
 635
 636 /*
 637  * This class represents a parsed call to a function, including calls
 638  * to system functions. The parameters in the parms list are the
 639  * expressions that are passed as input to the ports of the function.
 640  */
 641 class PECallFunction : public PExpr {
 642     public:
 643       explicit PECallFunction(const pform_name_t&n, const svector<PExpr *> &parms);
 644         // Call of system function (name is not heirarchical)
 645       explicit PECallFunction(perm_string n, const svector<PExpr *> &parms);
 646       explicit PECallFunction(perm_string n);
 647       ~PECallFunction();
 648
 649       virtual void dump(ostream &) const;
 650
 651       virtual NetNet* elaborate_net(Design*des, NetScope*scope,
 652                                     unsigned width,
 653                                     const NetExpr* rise,
 654                                     const NetExpr* fall,
 655                                     const NetExpr* decay,
 656                                     Link::strength_t drive0,
 657                                     Link::strength_t drive1) const;
 658       virtual NetExpr*elaborate_expr(Design*des, NetScope*scope,
 659                                      int expr_wid, bool sys_task_arg) const;
 660
 661       virtual unsigned test_width(Design*des, NetScope*scope,
 662                                   unsigned min, unsigned lval,
 663                                   bool&unsized_flag) const;
 664
 665     private:
 666       pform_name_t path_;
 667       svector<PExpr *> parms_;
 668
 669       bool check_call_matches_definition_(Design*des, NetScope*dscope) const;
 670
 671       NetExpr* elaborate_sfunc_(Design*des, NetScope*scope, int expr_wid) const;
 672       NetNet* elaborate_net_sfunc_(Design*des, NetScope*scope,
 673                                    unsigned width,
 674                                    const NetExpr* rise,
 675                                    const NetExpr* fall,
 676                                    const NetExpr* decay,
 677                                    Link::strength_t drive0,
 678                                    Link::strength_t drive1) const;
 679       unsigned test_width_sfunc_(Design*des, NetScope*scope,
 680                                  unsigned min, unsigned lval,
 681                                  bool&unsized_flag) const;
 682 };
 683
 684 #endif