iverilog/vvp/functor.h

171 lines
5.2 KiB
C++

#ifndef __functor_H
#define __functor_H
/*
* Copyright (c) 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
*/
#ifdef HAVE_CVS_IDENT
#ident "$Id: functor.h,v 1.57 2005/04/28 04:59:53 steve Exp $"
#endif
/* NOTE: THIS FILE IS BEOING PHASED OUT. IT'S FUNCTIONALITY IS OBSOLETE. */
# include "pointers.h"
# include "delay.h"
/*
* The vvp_ipoint_t is an integral type that is 32bits. The low 2 bits
* select the port of the referenced functor, and the remaining 30
* index the functor itself. All together, the 32 bits can completely
* identify any input of any functor.
*
* Outputs of functors are the heads of a linked list of all the
* inputs that it is connected to. The vvp_ipoint_t in .out points to
* the first port in the list. The .port[x] in turn points to the next
* port, and so on. The last .port[x] contains the null vvp_ipoint_t
* value zero (0). In this way, an output can fan out as wide as the
* original design requires.
*
* Value Encoding
* 1'b0 : 00
* 1'b1 : 01
* 1'bx : 10
* 1'bz : 11
*
* DRIVE STRENGTHS:
*
* The normal functor is not aware of strengths. It
* generates strength simply by virtue of having strength
* specifications. The drive strength specification includes a drive0
* and drive1 strength, each with 8 possible values (that can be
* represented in 3 bits) as given in this table:
*
* HiZ = 0,
* SMALL = 1,
* MEDIUM = 2,
* WEAK = 3,
* LARGE = 4,
* PULL = 5,
* STRONG = 6,
* SUPPLY = 7
*
* The output value (cval) is combined with the drive specifications
* to make a fully strength aware output, as described below.
*
* OUTPUT STRENGTHS:
*
* The strength-aware outputs are specified as an 8 bit value, that is
* two 4 bit numbers. The value is encoded with two drive strengths (0-7)
* and two drive values (0 or 1). Each nibble contains three bits of
* strength and one bit of value, like so: VSSS. The high nibble has
* the strength-value closest to supply1, and the low nibble has the
* strength-value closest to supply0.
*
* The functor calculates, when it operates, a 4-value output into
* oval and a fully strength aware value into ostr. Functors with
* fixed drive strength use the odrive0 and odrive1 fields to form the
* strength value.
*/
/*
* signal strengths
*/
enum strength_e {
HiZ = 0x00,
Su0 = 0x77, /* Su0-Su0 */
St0 = 0x66, /* St0-St0 */
Pu0 = 0x55, /* Pu0-Pu0 */
We0 = 0x33, /* We0-We0 */
Su1 = 0x77|0x88, /* Su1 - Su1 */
St1 = 0x66|0x88, /* St1 - St1 */
Pu1 = 0x55|0x88, /* Pu1 - Pu1 */
We1 = 0x33|0x88, /* We1 - We1 */
StX = 0x66|0x80, /* St0 - St1 */
};
/*
** The functor object
*/
struct functor_s {
functor_s();
virtual ~functor_s();
/* delay object */
vvp_delay_t delay;
/* This is the output for the device. */
vvp_ipoint_t out;
/* These are the input ports. */
vvp_ipoint_t port[4];
/* Input values without strengths. */
unsigned ival : 8;
private:
/* Output value (low bits) and drive1 and drive0 strength. */
unsigned cval : 2;
protected:
unsigned odrive0 : 3;
unsigned odrive1 : 3;
private:
/* Strength form of the output value. */
unsigned cstr : 8;
protected:
unsigned ostr : 8;
unsigned oval : 2;
private:
unsigned inhibit : 1;
public:
virtual void set(vvp_ipoint_t ipt, bool push,
unsigned val, unsigned str = 0) = 0;
inline unsigned char get() { return cval; }
inline unsigned char get_str() { return cstr; }
inline unsigned char get_oval() { return oval; }
inline unsigned char get_ostr() { return ostr; }
void put(vvp_ipoint_t ipt, unsigned val);
void put_oval(unsigned val,
bool push, bool nba_flag =false);
void put_ostr(unsigned val, unsigned str,
bool push, bool nba_flag=false);
// Schedule the functor to propagate. If the nba_flag is true,
// then schedule this as a non-blocking
// assignment. (sequential primitives use this feature.)
void schedule(vvp_time64_t delay, bool nba_flag =false);
bool disable(vvp_ipoint_t ptr);
bool enable(vvp_ipoint_t ptr);
void propagate(bool push);
void propagate(unsigned val, unsigned str, bool push);
};
/*
* $Log: functor.h,v $
* Revision 1.57 2005/04/28 04:59:53 steve
* Remove dead functor code.
*
* Revision 1.56 2005/04/03 06:16:54 steve
* Remove dead fvectors class.
*/
#endif