Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

748 lines (592 sloc) 24.758 kb
#ifndef __PExpr_H
#define __PExpr_H
/*
* Copyright (c) 1998-2011 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
*/
# include <string>
# include <vector>
# include <valarray>
# include "netlist.h"
# include "verinum.h"
# include "LineInfo.h"
# include "pform_types.h"
class Design;
class Module;
class LexicalScope;
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.
*/
class PExpr : public LineInfo {
public:
enum width_mode_t { SIZED, EXPAND, LOSSLESS, UNSIZED };
// Flag values that can be passed to elaborate_expr.
static const unsigned NO_FLAGS = 0x0;
static const unsigned NEED_CONST = 0x1;
static const unsigned SYS_TASK_ARG = 0x2;
PExpr();
virtual ~PExpr();
virtual void dump(ostream&) const;
// This method tests whether the expression contains any identifiers
// that have not been previously declared in the specified scope or
// in any containing scope. Any such identifiers are added to the
// specified scope as scalar nets of the specified type.
//
// This operation must be performed by the parser, to ensure that
// subsequent declarations do not affect the decision to create an
// implicit net.
virtual void declare_implicit_nets(LexicalScope*scope, NetNet::Type type);
// This method tests whether the expression contains any
// references to automatically allocated variables.
virtual bool has_aa_term(Design*des, NetScope*scope) const;
// This method tests the type and width that the expression wants
// to be. It should be called before elaborating an expression to
// figure out the type and width of the expression. It also figures
// out the minimum width that can be used to evaluate the expression
// without changing the result. This allows the expression width to
// be pruned when not all bits of the result are used.
//
// Normally mode should be initialised to SIZED before starting to
// test the width of an expression. In SIZED mode the expression
// width will be calculated strictly according to the IEEE standard
// rules for expression width.
// If the expression contains an unsized literal, mode will be
// changed to LOSSLESS. In LOSSLESS mode the expression width will
// be calculated as the minimum width necessary to avoid arithmetic
// overflow or underflow.
// If the expression both contains an unsized literal and contains
// an operation that coerces a vector operand to a different type
// (signed <-> unsigned), mode is changed to UNSIZED. UNSIZED mode
// is the same as LOSSLESS, except that the final expression width
// will be forced to be at least integer_width. This is necessary
// to ensure compatibility with the IEEE standard, which requires
// unsized literals to be treated as having the same width as an
// integer. The lossless width calculation is inadequate in this
// case because coercing an operand to a different type means that
// the expression no longer obeys the normal rules of arithmetic.
//
// If mode is initialised to EXPAND instead of SIZED, the expression
// width will be calculated as the minimum width necessary to avoid
// arithmetic overflow or underflow, even if it contains no unsized
// literals. mode will be changed LOSSLESS or UNSIZED as described
// above. This supports a non-standard mode of expression width
// calculation.
//
// When the final value of mode is UNSIZED, the width returned by
// this method is the calculated lossless width, but the width
// returned by a subsequent call to the expr_width method will be
// the final expression width.
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
// After the test_width method is complete, these methods
// return valid results.
ivl_variable_type_t expr_type() const { return expr_type_; }
unsigned expr_width() const { return expr_width_; }
unsigned min_width() const { return min_width_; }
bool has_sign() const { return signed_flag_; }
// This method allows the expression type (signed/unsigned)
// to be propagated down to any context-dependant operands.
void cast_signed(bool flag) { signed_flag_ = flag; }
// Procedural elaboration of the expression. The expr_width is
// the required width of the expression.
//
// The sys_task_arg flag is true if expressions are allowed to
// be incomplete.
virtual NetExpr*elaborate_expr(Design*des, NetScope*scope,
unsigned expr_wid,
unsigned flags) 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;
// This is similar to elaborate_lnet, except that the
// expression is evaluated to be bi-directional. This is
// useful for arguments to inout ports of module instances and
// ports of tran primitives.
virtual NetNet* elaborate_bi_net(Design*des, NetScope*scope) const;
// Expressions that can be in the l-value of procedural
// assignments can be elaborated with this method. If the
// is_force flag is true, then the set of valid l-value types
// is slightly modified to accommodate the Verilog force
// statement
virtual NetAssign_* elaborate_lval(Design*des,
NetScope*scope,
bool is_force) 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(Design*des, NetScope*sc) const;
// This method returns true if the expression represents a
// structural net that can have multiple drivers. This is
// used to test whether an input port connection can be
// collapsed to a single wire.
virtual bool is_collapsible_net(Design*des, NetScope*scope) 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;
protected:
unsigned fix_width_(width_mode_t mode);
// The derived class test_width methods should fill these in.
ivl_variable_type_t expr_type_;
unsigned expr_width_;
unsigned min_width_;
bool signed_flag_;
private: // not implemented
PExpr(const PExpr&);
PExpr& operator= (const PExpr&);
};
ostream& operator << (ostream&, const PExpr&);
class PEConcat : public PExpr {
public:
PEConcat(const list<PExpr*>&p, PExpr*r =0);
~PEConcat();
virtual verinum* eval_const(Design*des, NetScope*sc) const;
virtual void dump(ostream&) const;
virtual void declare_implicit_nets(LexicalScope*scope, NetNet::Type type);
virtual bool has_aa_term(Design*des, NetScope*scope) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
virtual NetNet* elaborate_lnet(Design*des, NetScope*scope) const;
virtual NetNet* elaborate_bi_net(Design*des, NetScope*scope) const;
virtual NetExpr*elaborate_expr(Design*des, NetScope*,
unsigned expr_wid,
unsigned flags) const;
virtual NetAssign_* elaborate_lval(Design*des,
NetScope*scope,
bool is_force) const;
virtual bool is_collapsible_net(Design*des, NetScope*scope) const;
private:
NetNet* elaborate_lnet_common_(Design*des, NetScope*scope,
bool bidirectional_flag) const;
private:
vector<PExpr*>parms_;
std::valarray<width_mode_t>width_modes_;
PExpr*repeat_;
NetScope*tested_scope_;
unsigned repeat_count_;
};
/*
* 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;
virtual bool has_aa_term(Design*des, NetScope*scope) 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(Design*des, NetScope*sc) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
virtual NetExpr*elaborate_expr(Design*des, NetScope*,
unsigned expr_wid,
unsigned flags) const;
virtual void dump(ostream&) const;
private:
verireal*value_;
};
class PEIdent : public PExpr {
public:
explicit PEIdent(perm_string, bool no_implicit_sig=false);
explicit PEIdent(const pform_name_t&);
~PEIdent();
// Add another name to the string of hierarchy that is the
// current identifier.
void append_name(perm_string);
virtual void dump(ostream&) const;
virtual void declare_implicit_nets(LexicalScope*scope, NetNet::Type type);
virtual bool has_aa_term(Design*des, NetScope*scope) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
// Identifiers are allowed (with restrictions) is assign l-values.
virtual NetNet* elaborate_lnet(Design*des, NetScope*scope) const;
virtual NetNet* elaborate_bi_net(Design*des, NetScope*scope) const;
// Identifiers are also allowed as procedural assignment l-values.
virtual NetAssign_* elaborate_lval(Design*des,
NetScope*scope,
bool is_force) const;
virtual NetExpr*elaborate_expr(Design*des, NetScope*,
unsigned expr_wid,
unsigned flags) 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;
verinum* eval_const(Design*des, NetScope*sc) const;
virtual bool is_collapsible_net(Design*des, NetScope*scope) const;
const pform_name_t& path() const { return path_; }
private:
pform_name_t path_;
bool no_implicit_sig_;
private:
// Common functions to calculate parts of part/bit
// selects. These methods return true if the expressions
// elaborate/calculate, or false if there is some sort of
// source error.
// The calculate_parts_ method calculates the range
// expressions of a part select for the current object. The
// part select expressions are elaborated and evaluated, and
// the values written to the msb/lsb arguments. If there are
// invalid bits (xz) in either expression, then the defined
// flag is set to *false*.
bool calculate_parts_(Design*, NetScope*, long&msb, long&lsb, bool&defined) const;
NetExpr* calculate_up_do_base_(Design*, NetScope*, bool need_const) const;
bool calculate_param_range_(Design*, NetScope*,
const NetExpr*msb_ex, long&msb,
const NetExpr*lsb_ex, long&lsb,
long length) const;
bool calculate_up_do_width_(Design*, NetScope*, unsigned long&wid) const;
private:
NetAssign_*elaborate_lval_net_word_(Design*, NetScope*, NetNet*) const;
bool elaborate_lval_net_bit_(Design*, NetScope*, NetAssign_*) const;
bool elaborate_lval_net_part_(Design*, NetScope*, NetAssign_*) const;
bool elaborate_lval_net_idx_(Design*, NetScope*, NetAssign_*,
index_component_t::ctype_t) const;
private:
NetExpr*elaborate_expr_param_(Design*des,
NetScope*scope,
const NetExpr*par,
NetScope*found,
const NetExpr*par_msb,
const NetExpr*par_lsb,
unsigned expr_wid,
unsigned flags) const;
NetExpr*elaborate_expr_param_part_(Design*des,
NetScope*scope,
const NetExpr*par,
NetScope*found,
const NetExpr*par_msb,
const NetExpr*par_lsb,
unsigned expr_wid) const;
NetExpr*elaborate_expr_param_idx_up_(Design*des,
NetScope*scope,
const NetExpr*par,
NetScope*found,
const NetExpr*par_msb,
const NetExpr*par_lsb,
bool need_const) const;
NetExpr*elaborate_expr_param_idx_do_(Design*des,
NetScope*scope,
const NetExpr*par,
NetScope*found,
const NetExpr*par_msb,
const NetExpr*par_lsb,
bool need_const) const;
NetExpr*elaborate_expr_net(Design*des,
NetScope*scope,
NetNet*net,
NetScope*found,
unsigned expr_wid,
unsigned flags) const;
NetExpr*elaborate_expr_net_word_(Design*des,
NetScope*scope,
NetNet*net,
NetScope*found,
unsigned expr_wid,
unsigned flags) const;
NetExpr*elaborate_expr_net_part_(Design*des,
NetScope*scope,
NetESignal*net,
NetScope*found,
unsigned expr_wid) const;
NetExpr*elaborate_expr_net_idx_up_(Design*des,
NetScope*scope,
NetESignal*net,
NetScope*found,
bool need_const) const;
NetExpr*elaborate_expr_net_idx_do_(Design*des,
NetScope*scope,
NetESignal*net,
NetScope*found,
bool need_const) const;
NetExpr*elaborate_expr_net_bit_(Design*des,
NetScope*scope,
NetESignal*net,
NetScope*found,
bool need_const) const;
private:
NetNet* elaborate_lnet_common_(Design*des, NetScope*scope,
bool bidirectional_flag) const;
bool eval_part_select_(Design*des, NetScope*scope, NetNet*sig,
long&midx, long&lidx) const;
};
class PENumber : public PExpr {
public:
explicit PENumber(verinum*vp);
~PENumber();
const verinum& value() const;
virtual void dump(ostream&) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
virtual NetEConst*elaborate_expr(Design*des, NetScope*,
unsigned expr_wid, unsigned) const;
virtual NetAssign_* elaborate_lval(Design*des,
NetScope*scope,
bool is_force) const;
virtual verinum* eval_const(Design*des, NetScope*sc) const;
virtual bool is_the_same(const PExpr*that) 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 unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
virtual NetEConst*elaborate_expr(Design*des, NetScope*,
unsigned expr_wid, unsigned) const;
verinum* eval_const(Design*, NetScope*) const;
private:
char*text_;
};
class PEUnary : public PExpr {
public:
explicit PEUnary(char op, PExpr*ex);
~PEUnary();
virtual void dump(ostream&out) const;
virtual void declare_implicit_nets(LexicalScope*scope, NetNet::Type type);
virtual bool has_aa_term(Design*des, NetScope*scope) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
virtual NetExpr*elaborate_expr(Design*des, NetScope*,
unsigned expr_wid,
unsigned flags) const;
virtual verinum* eval_const(Design*des, NetScope*sc) const;
private:
NetExpr* elaborate_expr_bits_(NetExpr*operand, unsigned expr_wid) const;
private:
char op_;
PExpr*expr_;
};
class PEBinary : public PExpr {
public:
explicit PEBinary(char op, PExpr*l, PExpr*r);
~PEBinary();
virtual void dump(ostream&out) const;
virtual void declare_implicit_nets(LexicalScope*scope, NetNet::Type type);
virtual bool has_aa_term(Design*des, NetScope*scope) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
virtual NetExpr*elaborate_expr(Design*des, NetScope*,
unsigned expr_wid,
unsigned flags) const;
virtual verinum* eval_const(Design*des, NetScope*sc) const;
protected:
char op_;
PExpr*left_;
PExpr*right_;
NetExpr*elaborate_expr_base_(Design*, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) const;
NetExpr*elaborate_eval_expr_base_(Design*, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) const;
NetExpr*elaborate_expr_base_bits_(Design*, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) const;
NetExpr*elaborate_expr_base_div_(Design*, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) const;
NetExpr*elaborate_expr_base_mult_(Design*, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) const;
NetExpr*elaborate_expr_base_add_(Design*, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) const;
};
/*
* Here are a few specialized classes for handling specific binary
* operators.
*/
class PEBComp : public PEBinary {
public:
explicit PEBComp(char op, PExpr*l, PExpr*r);
~PEBComp();
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
NetExpr* elaborate_expr(Design*des, NetScope*scope,
unsigned expr_wid, unsigned flags) const;
private:
unsigned l_width_;
unsigned r_width_;
};
/*
* This derived class is for handling logical expressions: && and ||.
*/
class PEBLogic : public PEBinary {
public:
explicit PEBLogic(char op, PExpr*l, PExpr*r);
~PEBLogic();
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
NetExpr* elaborate_expr(Design*des, NetScope*scope,
unsigned expr_wid, unsigned flags) const;
};
/*
* A couple of the binary operands have a special sub-expression rule
* where the expression width is carried entirely by the left
* expression, and the right operand is self-determined.
*/
class PEBLeftWidth : public PEBinary {
public:
explicit PEBLeftWidth(char op, PExpr*l, PExpr*r);
~PEBLeftWidth() =0;
virtual NetExpr*elaborate_expr_leaf(Design*des, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) const =0;
protected:
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
virtual NetExpr*elaborate_expr(Design*des, NetScope*scope,
unsigned expr_wid,
unsigned flags) const;
};
class PEBPower : public PEBLeftWidth {
public:
explicit PEBPower(char op, PExpr*l, PExpr*r);
~PEBPower();
NetExpr*elaborate_expr_leaf(Design*des, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) const;
};
class PEBShift : public PEBLeftWidth {
public:
explicit PEBShift(char op, PExpr*l, PExpr*r);
~PEBShift();
NetExpr*elaborate_expr_leaf(Design*des, NetExpr*lp, NetExpr*rp,
unsigned expr_wid) 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 void dump(ostream&out) const;
virtual void declare_implicit_nets(LexicalScope*scope, NetNet::Type type);
virtual bool has_aa_term(Design*des, NetScope*scope) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
virtual NetExpr*elaborate_expr(Design*des, NetScope*,
unsigned expr_wid,
unsigned flags) const;
virtual verinum* eval_const(Design*des, NetScope*sc) const;
private:
NetExpr* elab_and_eval_alternative_(Design*des, NetScope*scope,
PExpr*expr, unsigned expr_wid,
unsigned flags) 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 pform_name_t&n, const vector<PExpr *> &parms);
// Call of system function (name is not hierarchical)
explicit PECallFunction(perm_string n, const vector<PExpr *> &parms);
explicit PECallFunction(perm_string n);
// svector versions. Should be removed!
explicit PECallFunction(const pform_name_t&n, const list<PExpr *> &parms);
explicit PECallFunction(perm_string n, const list<PExpr *> &parms);
~PECallFunction();
virtual void dump(ostream &) const;
virtual void declare_implicit_nets(LexicalScope*scope, NetNet::Type type);
virtual bool has_aa_term(Design*des, NetScope*scope) const;
virtual NetExpr*elaborate_expr(Design*des, NetScope*scope,
unsigned expr_wid,
unsigned flags) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
private:
pform_name_t path_;
vector<PExpr *> parms_;
bool check_call_matches_definition_(Design*des, NetScope*dscope) const;
NetExpr* cast_to_width_(NetExpr*expr, unsigned wid) const;
NetExpr* elaborate_sfunc_(Design*des, NetScope*scope,
unsigned expr_wid,
unsigned flags) const;
NetExpr* elaborate_access_func_(Design*des, NetScope*scope, ivl_nature_t,
unsigned expr_wid) const;
unsigned test_width_sfunc_(Design*des, NetScope*scope,
width_mode_t&mode);
};
/*
* Support the SystemVerilog cast to size.
*/
class PECastSize : public PExpr {
public:
explicit PECastSize(unsigned expr_wid, PExpr*base);
~PECastSize();
void dump(ostream &out) const;
virtual NetExpr*elaborate_expr(Design*des, NetScope*scope,
unsigned expr_wid,
unsigned flags) const;
virtual unsigned test_width(Design*des, NetScope*scope,
width_mode_t&mode);
private:
unsigned size_;
PExpr* base_;
};
/*
* This class is used for error recovery. All methods do nothing and return
* null or default values.
*/
class PEVoid : public PExpr {
public:
explicit PEVoid();
~PEVoid();
virtual NetExpr*elaborate_expr(Design*des, NetScope*scope,
unsigned expr_wid,
unsigned flags) const;
};
#endif
Jump to Line
Something went wrong with that request. Please try again.