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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 1.59 2002/04/23 03:53:59 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. Set thie
// bare_memory_ok flag if the result is allowed to be a
// NetEMemory without an index.
      virtual NetExpr*elaborate_expr(Design*des, NetScope*scope,
bool sys_task_arg =false) 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, NetScope*scope,
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, NetScope*scope) 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 NetScope*sc) 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, NetScope*scope) const;
      virtual NetNet* elaborate_net(Design*des, NetScope*scope,
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*,
bool sys_task_arg =false) 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 NetScope*sc) 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*,
bool sys_task_arg =false) 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 hname_t&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, NetScope*scope) 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, NetScope*scope,
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*,
bool sys_task_arg =false) 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 NetScope*sc) const;
      verireal*eval_rconst(const Design*des, const NetScope*sc) const;

      const hname_t& path() const;

    private:
      hname_t path_;

    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, NetScope*scope,
NetMemory*mem, unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;

      NetNet* elaborate_net_bitmux_(Design*des, NetScope*scope,
NetNet*sig,
unsigned long rise,
unsigned long fall,
unsigned long decay,
Link::strength_t drive0,
Link::strength_t drive1) 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, NetScope*scope,
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*,
bool sys_task_arg =false) const;
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
      virtual NetAssign_* elaborate_lval(Design*des, NetScope*scope) const;

      virtual verinum* eval_const(const Design*des, const NetScope*sc) const;
      virtual verireal*eval_rconst(const Design*, const NetScope*) const;

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

    private:
      verinum*const value_;
};

/*
* This represents a string constant in an expression.
*
* The s parameter to the PEString constructor is a C string that this
* class instance will take for its own. The caller should not delete
* the string, the destructor will do it.
*/
class PEString : public PExpr {

    public:
      explicit PEString(char*s);
      ~PEString();

      string value() const;
      virtual void dump(ostream&) const;
      virtual NetNet* elaborate_net(Design*des, NetScope*scope,
unsigned width,
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*,
bool sys_task_arg =false) const;
      virtual NetEConst*elaborate_pexpr(Design*des, NetScope*sc) const;

      virtual bool is_constant(Module*) const;

    private:
      char*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, NetScope*scope,
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*,
bool sys_task_arg =false) const;
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
      virtual verinum* eval_const(const Design*des, const NetScope*sc) 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);
      ~PEBinary();

      virtual bool is_constant(Module*) const;

      virtual void dump(ostream&out) const;
      virtual NetNet* elaborate_net(Design*des, NetScope*scope,
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*,
bool sys_task_arg =false) const;
      virtual NetExpr*elaborate_pexpr(Design*des, NetScope*sc) const;
      virtual verinum* eval_const(const Design*des, const NetScope*sc) const;
      virtual verireal*eval_rconst(const Design*des, const NetScope*sc) const;

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

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

      NetNet* elaborate_net_add_(Design*des, NetScope*scope,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_bit_(Design*des, NetScope*scope,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_cmp_(Design*des, NetScope*scope,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_div_(Design*des, NetScope*scope,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_mod_(Design*des, NetScope*scope,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_log_(Design*des, NetScope*scope,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_mul_(Design*des, NetScope*scope,
unsigned lwidth,
unsigned long rise,
unsigned long fall,
unsigned long decay) const;
      NetNet* elaborate_net_shift_(Design*des, NetScope*scope,
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, NetScope*scope,
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*,
bool sys_task_arg =false) const;
      virtual NetETernary*elaborate_pexpr(Design*des, NetScope*sc) const;
      virtual verinum* eval_const(const Design*des, const NetScope*sc) const;

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

/*
* This class represents a parsed call to a function, including calls
* to system functions. The parameters in the parms list are the
* expressions that are passed as input to the ports of the function.
*/
class PECallFunction : public PExpr {
    public:
      explicit PECallFunction(const hname_t&n, const svector<PExpr *> &parms);
      explicit PECallFunction(const hname_t&n);
      ~PECallFunction();

      virtual void dump(ostream &) const;
      virtual NetNet* elaborate_net(Design*des, NetScope*scope,
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*scope,
bool sys_task_arg =false) const;

    private:
      hname_t path_;
      svector<PExpr *> parms_;

      bool check_call_matches_definition_(Design*des, NetScope*dscope) const;

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

/*
* $Log: PExpr.h,v $
* Revision 1.59 2002/04/23 03:53:59 steve
* Add support for non-constant bit select.
*
* Revision 1.58 2002/04/14 03:55:25 steve
* Precalculate unary - if possible.
*
* Revision 1.57 2002/04/13 02:33:17 steve
* Detect missing indices to memories (PR#421)
*
* Revision 1.56 2002/03/09 04:02:26 steve
* Constant expressions are not l-values for task ports.
*
* Revision 1.55 2002/03/09 02:10:22 steve
* Add the NetUserFunc netlist node.
*
* Revision 1.54 2001/12/30 21:32:03 steve
* Support elaborate_net for PEString objects.
*
* Revision 1.53 2001/12/03 04:47:14 steve
* Parser and pform use hierarchical names as hname_t
* objects instead of encoded strings.
*
* Revision 1.52 2001/11/08 05:15:50 steve
* Remove string paths from PExpr elaboration.
*
* Revision 1.51 2001/11/07 04:26:46 steve
* elaborate_lnet uses scope instead of string path.
*
* Revision 1.50 2001/11/07 04:01:59 steve
* eval_const uses scope instead of a string path.
*/
#endif
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