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#ifndef __PExpr_H
#define __PExpr_H
/*
* Copyright (c) 1998-2000 Stephen Williams <steve@icarus.com>
*
* This source code is free software; you can redistribute it
* and/or modify it in source code form under the terms of the GNU
* General Public License as published by the Free Software
* Foundation; either version 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#if !defined(WINNT) && !defined(macintosh)
#ident "$Id: PExpr.h,v 1.48 2001/01/14 23:04:55 steve Exp $"
#endif

# include <string>
# include "netlist.h"
# include "verinum.h"
# include "verireal.h"
# include "LineInfo.h"

class Design;
class Module;
class NetNet;
class NetExpr;
class NetScope;

/*
* The PExpr class hierarchy supports the description of
* expressions. The parser can generate expression objects from the
* source, possibly reducing things that it knows how to reduce.
*
* The elaborate_net method is used by structural elaboration to build
* up a netlist interpretation of the expression.
*/

class PExpr : public LineInfo {

    public:
      PExpr();
      virtual ~PExpr();

      virtual void dump(ostream&) const;

// Procedural elaboration of the expression.
      virtual NetExpr*elaborate_expr(Design*des, NetScope*scope) const;

// Elaborate expressions that are the r-value of parameter
// assignments. This elaboration follows the restrictions of
// constant expressions and supports later overriding and
// evaluation of parameters.
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;

// This method elaborate the expression as gates, for use in a
// continuous assign or other wholly structural context.
      virtual NetNet* elaborate_net(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay,
Link::strength_t drive0 =Link::STRONG,
Link::strength_t drive1 =Link::STRONG)
const;

// This method elaborates the expression as NetNet objects. It
// only allows regs suitable for procedural continuous assignments.
      virtual NetNet* elaborate_anet(Design*des, NetScope*scope) const;

// This method elaborates the expression as gates, but
// restricted for use as l-values of continuous assignments.
      virtual NetNet* elaborate_lnet(Design*des, const string&path) const;

// Expressions that can be in the l-value of procedural
// assignments can be elaborated with this method.
      virtual NetAssign_* elaborate_lval(Design*des, NetScope*scope) const;

// This attempts to evaluate a constant expression, and return
// a verinum as a result. If the expression cannot be
// evaluated, return 0.
      virtual verinum* eval_const(const Design*des, const string&path) const;

// This attempts to evaluate a constant expression as a
// decimal floating point. This is used when calculating delay
// constants.
      virtual verireal* eval_rconst(const Design*, const NetScope*) const;

// This method returns true if that expression is the same as
// this expression. This method is used for comparing
// expressions that must be structurally "identical".
      virtual bool is_the_same(const PExpr*that) const;

// Return true if this expression is a valid constant
// expression. the Module pointer is needed to find parameter
// identifiers and any other module specific interpretations
// of expresions.
      virtual bool is_constant(Module*) const;

    private: // not implemented
      PExpr(const PExpr&);
      PExpr& operator= (const PExpr&);
};

ostream& operator << (ostream&, const PExpr&);

class PEConcat : public PExpr {

    public:
      PEConcat(const svector<PExpr*>&p, PExpr*r =0);
      ~PEConcat();

      virtual void dump(ostream&) const;

// Concatenated Regs can be on the left of procedural
// continuous assignments.
      virtual NetNet* elaborate_anet(Design*des, NetScope*scope) const;

      virtual NetNet* elaborate_lnet(Design*des, const string&path) const;
      virtual NetNet* elaborate_net(Design*des, const string&path,
unsigned width,
unsigned long rise,
unsigned long fall,
unsigned long decay,
Link::strength_t drive0,
Link::strength_t drive1) const;
      virtual NetExpr*elaborate_expr(Design*des, NetScope*) const;
      virtual NetEConcat*elaborate_pexpr(Design*des, NetScope*) const;
      virtual NetAssign_* elaborate_lval(Design*des, NetScope*scope) const;
      virtual bool is_constant(Module*) const;

    private:
      svector<PExpr*>parms_;
      PExpr*repeat_;
};

/*
* Event expressions are expressions that can be combined with the
* event "or" operator. These include "posedge foo" and similar, and
* also include named events. "edge" events are associated with an
* expression, whereas named events simply have a name, which
* represents an event variable.
*/
class PEEvent : public PExpr {

    public:
      enum edge_t {ANYEDGE, POSEDGE, NEGEDGE, POSITIVE};

// Use this constructor to create events based on edges or levels.
      PEEvent(edge_t t, PExpr*e);

      ~PEEvent();

      edge_t type() const;
      PExpr* expr() const;
 
      virtual void dump(ostream&) const;

    private:
      edge_t type_;
      PExpr *expr_;
};

/*
* This holds a floating point constant in the source.
*/
class PEFNumber : public PExpr {

    public:
      explicit PEFNumber(verireal*vp);
      ~PEFNumber();

      const verireal& value() const;

/* The eval_const method as applied to a floating point number
gets the *integer* value of the number. This accounts for
any rounding that is needed to get the value. */
      virtual verinum* eval_const(const Design*des, const string&path) const;

/* This method returns the full floating point value. */
      virtual verireal* eval_rconst(const Design*, const NetScope*) const;

/* A PEFNumber is a constant, so this returns true. */
      virtual bool is_constant(Module*) const;

      virtual NetExpr*elaborate_expr(Design*des, NetScope*) const;
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;

      virtual void dump(ostream&) const;

    private:
      verireal*value_;
};

class PEIdent : public PExpr {

    public:
      explicit PEIdent(const string&s);
      ~PEIdent();

      virtual void dump(ostream&) const;

// Regs can be on the left of procedural continuous assignments
      virtual NetNet* elaborate_anet(Design*des, NetScope*scope) const;

// Identifiers are allowed (with restrictions) is assign l-values.
      virtual NetNet* elaborate_lnet(Design*des, const string&path) const;

// Identifiers are also allowed as procedural assignment l-values.
      virtual NetAssign_* elaborate_lval(Design*des, NetScope*scope) const;

// Structural r-values are OK.
      virtual NetNet* elaborate_net(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay,
Link::strength_t drive0,
Link::strength_t drive1) const;

      virtual NetExpr*elaborate_expr(Design*des, NetScope*) const;
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;

// Elaborate the PEIdent as a port to a module. This method
// only applies to Ident expressions.
      NetNet* elaborate_port(Design*des, NetScope*sc) const;

      virtual bool is_constant(Module*) const;
      verinum* eval_const(const Design*des, const string&path) const;

      string name() const;

    private:
      string text_;

    public:
// Use these to support bit- and part-select operators.
      PExpr*msb_;
      PExpr*lsb_;

// If this is a reference to a memory, this is the index
// expression.
      PExpr*idx_;

      NetNet* elaborate_net_ram_(Design*des, const string&path,
NetMemory*mem, unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
};

class PENumber : public PExpr {

    public:
      explicit PENumber(verinum*vp);
      ~PENumber();

      const verinum& value() const;

      virtual void dump(ostream&) const;
      virtual NetNet* elaborate_net(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay,
Link::strength_t drive0,
Link::strength_t drive1) const;
      virtual NetEConst*elaborate_expr(Design*des, NetScope*) const;
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
      virtual verinum* eval_const(const Design*des, const string&path) const;

      virtual bool is_the_same(const PExpr*that) const;
      virtual bool is_constant(Module*) const;

    private:
      verinum*const value_;
};

class PEString : public PExpr {

    public:
      explicit PEString(const string&s);
      ~PEString();

      string value() const;
      virtual void dump(ostream&) const;
      virtual NetEConst*elaborate_expr(Design*des, NetScope*) const;
      virtual NetEConst*elaborate_pexpr(Design*des, NetScope*sc) const;

      virtual bool is_constant(Module*) const;

    private:
      const string text_;
};

class PEUnary : public PExpr {

    public:
      explicit PEUnary(char op, PExpr*ex);
      ~PEUnary();

      virtual void dump(ostream&out) const;
      virtual NetNet* elaborate_net(Design*des, const string&path,
unsigned width,
unsigned long rise,
unsigned long fall,
unsigned long decay,
Link::strength_t drive0,
Link::strength_t drive1) const;
      virtual NetEUnary*elaborate_expr(Design*des, NetScope*) const;
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
      virtual verinum* eval_const(const Design*des, const string&path) const;

      virtual bool is_constant(Module*) const;

    private:
      char op_;
      PExpr*expr_;
};

class PEBinary : public PExpr {

    public:
      explicit PEBinary(char op, PExpr*l, PExpr*r)
      : op_(op), left_(l), right_(r) { }

      virtual bool is_constant(Module*) const;

      virtual void dump(ostream&out) const;
      virtual NetNet* elaborate_net(Design*des, const string&path,
unsigned width,
unsigned long rise,
unsigned long fall,
unsigned long decay,
Link::strength_t drive0,
Link::strength_t drive1) const;
      virtual NetEBinary*elaborate_expr(Design*des, NetScope*) const;
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
      virtual verinum* eval_const(const Design*des, const string&path) const;

    private:
      char op_;
      PExpr*left_;
      PExpr*right_;

      NetEBinary*elaborate_expr_base_(Design*, NetExpr*lp, NetExpr*rp) const;

      NetNet* elaborate_net_add_(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_bit_(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_cmp_(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_div_(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_mod_(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_log_(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_mul_(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_shift_(Design*des, const string&path,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
};

/*
* This class supports the ternary (?:) operator. The operator takes
* three expressions, the test, the true result and the false result.
*/
class PETernary : public PExpr {

    public:
      explicit PETernary(PExpr*e, PExpr*t, PExpr*f);
      ~PETernary();

      virtual bool is_constant(Module*) const;

      virtual void dump(ostream&out) const;
      virtual NetNet* elaborate_net(Design*des, const string&path,
unsigned width,
unsigned long rise,
unsigned long fall,
unsigned long decay,
Link::strength_t drive0,
Link::strength_t drive1) const;
      virtual NetETernary*elaborate_expr(Design*des, NetScope*) const;
      virtual NetETernary*elaborate_pexpr(Design*des, NetScope*sc) const;
      virtual verinum* eval_const(const Design*des, const string&path) const;

    private:
      PExpr*expr_;
      PExpr*tru_;
      PExpr*fal_;
};

/*
* This class represents a parsed call to a function, including calls
* to system functions.
*/
class PECallFunction : public PExpr {
    public:
      explicit PECallFunction(const char*n, const svector<PExpr *> &parms);
      explicit PECallFunction(const char*n);
      ~PECallFunction();

      virtual void dump(ostream &) const;
      virtual NetExpr*elaborate_expr(Design*des, NetScope*scope) const;

    private:
      string name_;
      svector<PExpr *> parms_;

      NetExpr* elaborate_sfunc_(Design*des, NetScope*scope) const;
};

/*
* $Log: PExpr.h,v $
* Revision 1.48 2001/01/14 23:04:55 steve
* Generalize the evaluation of floating point delays, and
* get it working with delay assignment statements.
*
* Allow parameters to be referenced by hierarchical name.
*
* Revision 1.47 2000/12/16 19:03:30 steve
* Evaluate <= and ?: in parameter expressions (PR#81)
*
* Revision 1.46 2000/12/10 22:01:35 steve
* Support decimal constants in behavioral delays.
*
* Revision 1.45 2000/12/06 06:31:09 steve
* Check lvalue of procedural continuous assign (PR#29)
*
* Revision 1.44 2000/09/17 21:26:15 steve
* Add support for modulus (Eric Aardoom)
*
* Revision 1.43 2000/09/09 15:21:26 steve
* move lval elaboration to PExpr virtual methods.
*
* Revision 1.42 2000/09/07 22:38:13 steve
* Support unary + and - in constants.
*
* Revision 1.41 2000/06/30 15:50:20 steve
* Allow unary operators in constant expressions.
*
* Revision 1.40 2000/06/13 05:22:16 steve
* Support concatenation in parameter expressions.
*
* Revision 1.39 2000/06/01 02:31:39 steve
* Parameters can be strings.
*
* Revision 1.38 2000/05/16 04:05:15 steve
* Module ports are really special PEIdent
* expressions, because a name can be used
* many places in the port list.
*
* Revision 1.37 2000/05/07 04:37:56 steve
* Carry strength values from Verilog source to the
* pform and netlist for gates.
*
* Change vvm constants to use the driver_t to drive
* a constant value. This works better if there are
* multiple drivers on a signal.
*
* Revision 1.36 2000/05/04 03:37:58 steve
* Add infrastructure for system functions, move
* $time to that structure and add $random.
*
* Revision 1.35 2000/04/12 04:23:57 steve
* Named events really should be expressed with PEIdent
* objects in the pform,
*
* Handle named events within the mix of net events
* and edges. As a unified lot they get caught together.
* wait statements are broken into more complex statements
* that include a conditional.
*
* Do not generate NetPEvent or NetNEvent objects in
* elaboration. NetEvent, NetEvWait and NetEvProbe
* take over those functions in the netlist.
*
* Revision 1.34 2000/04/01 21:40:22 steve
* Add support for integer division.
*
* Revision 1.33 2000/04/01 19:31:57 steve
* Named events as far as the pform.
*
* Revision 1.32 2000/03/12 18:22:11 steve
* Binary and unary operators in parameter expressions.
*
* Revision 1.31 2000/03/12 04:35:22 steve
* Allow parameter identifiers in parameter expressions.
*
* Revision 1.30 2000/03/08 04:36:53 steve
* Redesign the implementation of scopes and parameters.
* I now generate the scopes and notice the parameters
* in a separate pass over the pform. Once the scopes
* are generated, I can process overrides and evalutate
* paremeters before elaboration begins.
*
* Revision 1.29 2000/02/23 02:56:53 steve
* Macintosh compilers do not support ident.
*
* Revision 1.28 2000/02/16 03:58:27 steve
* Fix up width matching in structural bitwise operators.
*
* Revision 1.27 2000/01/13 03:35:35 steve
* Multiplication all the way to simulation.
*
* Revision 1.26 1999/12/16 03:46:39 steve
* Structural logical or.
*
* Revision 1.25 1999/11/21 00:13:08 steve
* Support memories in continuous assignments.
*
* Revision 1.24 1999/11/14 20:24:28 steve
* Add support for the LPM_CLSHIFT device.
*
* Revision 1.23 1999/11/05 21:45:19 steve
* Fix NetConst being set to zero width, and clean
* up elaborate_set_cmp_ for NetEBinary.
*
* Revision 1.22 1999/10/31 20:08:24 steve
* Include subtraction in LPM_ADD_SUB device.
*
* Revision 1.21 1999/10/31 04:11:27 steve
* Add to netlist links pin name and instance number,
* and arrange in vvm for pin connections by name
* and instance number.
*
* Revision 1.20 1999/09/25 02:57:29 steve
* Parse system function calls.
*
* Revision 1.19 1999/09/15 04:17:52 steve
* separate assign lval elaboration for error checking.
*
* Revision 1.18 1999/08/31 22:38:29 steve
* Elaborate and emit to vvm procedural functions.
*
* Revision 1.17 1999/08/01 21:18:55 steve
* elaborate rise/fall/decay for continuous assign.
*
* Revision 1.16 1999/07/31 19:14:47 steve
* Add functions up to elaboration (Ed Carter)
*
* Revision 1.15 1999/07/22 02:05:20 steve
* is_constant method for PEConcat.
*
* Revision 1.14 1999/07/17 19:50:59 steve
* netlist support for ternary operator.
*
* Revision 1.13 1999/06/16 03:13:29 steve
* More syntax parse with sorry stubs.
*
* Revision 1.12 1999/06/15 02:50:02 steve
* Add lexical support for real numbers.
*
* Revision 1.11 1999/06/10 04:03:52 steve
* Add support for the Ternary operator,
* Add support for repeat concatenation,
* Correct some seg faults cause by elaboration
* errors,
* Parse the casex anc casez statements.
*
* Revision 1.10 1999/06/09 03:00:05 steve
* Add support for procedural concatenation expression.
*
* Revision 1.9 1999/05/16 05:08:42 steve
* Redo constant expression detection to happen
* after parsing.
*
* Parse more operators and expressions.
*
* Revision 1.8 1999/05/10 00:16:57 steve
* Parse and elaborate the concatenate operator
* in structural contexts, Replace vector<PExpr*>
* and list<PExpr*> with svector<PExpr*>, evaluate
* constant expressions with parameters, handle
* memories as lvalues.
*
* Parse task declarations, integer types.
*
* Revision 1.7 1999/05/01 02:57:52 steve
* Handle much more complex event expressions.
*
* Revision 1.6 1999/04/29 02:16:26 steve
* Parse OR of event expressions.
*
* Revision 1.5 1999/04/19 01:59:36 steve
* Add memories to the parse and elaboration phases.
*
* Revision 1.4 1998/11/11 00:01:51 steve
* Check net ranges in declarations.
*
* Revision 1.3 1998/11/09 18:55:33 steve
* Add procedural while loops,
* Parse procedural for loops,
* Add procedural wait statements,
* Add constant nodes,
* Add XNOR logic gate,
* Make vvm output look a bit prettier.
*
* Revision 1.2 1998/11/07 17:05:05 steve
* Handle procedural conditional, and some
* of the conditional expressions.
*
* Elaborate signals and identifiers differently,
* allowing the netlist to hold signal information.
*
* Revision 1.1 1998/11/03 23:28:54 steve
* Introduce verilog to CVS.
*
*/
#endif
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