byucc.jhdl.contrib.modgen
Class downcnt

java.lang.Object
  byucc.jhdl.base.Nameable
      byucc.jhdl.base.Node
          byucc.jhdl.base.Cell
              byucc.jhdl.base.Structural
                  byucc.jhdl.Logic.LogicGates
                      byucc.jhdl.Logic.LogicStatic
                          byucc.jhdl.Logic.Logic
                              byucc.jhdl.contrib.modgen.downcnt

All Implemented Interfaces:

BooleanFlags, Clockable, byucc.jhdl.base.Propagateable, TreeListable

public class downcnt

extends Logic

A generic sized down counter

Downcnt is a loadable, holdable down counter. The signal Term_cnt goes low when the counter contents are zero. All state changes occur on the rising edge. See the tables below for a better understanding on how this module works.

Clk_En	Load	Load_Data	Outnext
0	don't care	don't care	Out
1	0	don't care	Out - 1
1	1	data	data

Implementation

All Technologies

Downcnt implements a registered decrementer with a mux that selects between the decremented value, or the data on the load_data signal. The borrow-out of the decrementer serves as the term_cnt.

Xilinx XC4000

CLB count:

If width of output is even, # of CLBs = 1 + (width/2)

If width of output is odd, # of CLBs = 2 + (width/2)

CLB placement:

The CLBs are placed in a single column

Xilinx Virtex

Slice count:

If not using term_cnt, # of Slices = (width of output + 1)/2

If using term_cnt, # of Slices = width of output + 1

Slice placement:

The Slices are placed in a single column if term_cnt is tied to null. Otherwise, there are 2 columns, one of them is used to generate the term_cnt signal.

Version:

2.0

Author:

Tim Wheeler

Out

Outnext

Field Summary

static CellInterface[]	cell_interface
static java.lang.String	cellname The output is a generic width
static CellInterface[]	implicit_interface

Fields inherited from class byucc.jhdl.Logic.Logic

ABOVE, ALIGN_BOTTOM, ALIGN_CENTER, ALIGN_LEFT, ALIGN_LSB, ALIGN_MSB, ALIGN_RIGHT, ALIGN_TOP, BELOW, DOWN, EAST_OF, LEFT_OF, MAX_PACK, NORTH_OF, ON, ONTOP, ONTOP_OF, RIGHT_OF, SOUTH_OF, TOLEFT, TORIGHT, UNCONSTRAINED, UP, WEST_OF

Fields inherited from class byucc.jhdl.Logic.LogicGates

tech_mapper

Fields inherited from class byucc.jhdl.base.Cell

BOOLEAN, CELL_NAME_DECLARATION, CellInterfaceDeterminesUniqueNetlistStructure, DETERMINE_FROM_STRING, GENERICS_DECLARATION, IMPLICIT_INTERFACE_DECLARATION, INTEGER, INTERFACE_DECLARATION, LONG, PORT_IOS_DECLARATION, PORT_NAMES_DECLARATION, PORT_NET_NAMES_DECLARATION, PORT_PROPERTIES, PORT_WIDTHS_DECLARATION, SIGN_EXT, STRING, ZERO_PAD

Fields inherited from interface byucc.jhdl.base.BooleanFlags

ANTECEDANT_IS_BEHAVIORALLY_MODELED, ASYNC_PORT, ASYNCHRONOUS_RESOLVED, ATOMICALLY_PLACEABLE, ATOMICALLY_UNMAPPABLE, BEHAVIORALLY_MODELED_BRANCH, CLK_PORT, CLOCK_METHOD_IMPLEMENTED_BY_USER, CLOCK_METHOD_IS_DISABLED, CLOCKABLE_IS_SCHEDULED, DANGLING_IS_OK, DELETE_MARK, FATAL_BUILD_ERROR_OCCURED, HAS_BEEN_TRACED, HAS_USER_SPECIFIED_NAME, HWUPDATE, IMPLICIT_PORT, IN_CLK_PORT, IN_PORT, INOUT_PORT, IO_TYPE_FLAGS, IS_BEHAVIORALLY_MODELED, IS_ON_BUILD_STACK, IS_ON_PROP_LIST, IS_PLACED, METHODS_IMPLEMENTED_BY_USER, NETLISTABLE, ORIG_WIRE_IS_ATOMIC, OUT_PORT, PLACEMENT_IS_LOCKED, PROPAGATE_METHOD_IMPLEMENTED_BY_USER, PROPAGATE_METHOD_IS_DISABLED, RECURSION_FLAG, RESET_METHOD_IMPLEMENTED_BY_USER, SIMULATEABLE, SOURCELESS_IS_OK, SYNC_PORT, VISIBLE

Constructor Summary

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire out)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire out, long resetState)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire out, long resetState, java.lang.String name)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire out, java.lang.String name)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, BV resetState)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, BV resetState, java.lang.String name)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, long resetState)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, long resetState, java.lang.String name)

downcnt(Node parent, Wire clk, boolean b, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, java.lang.String name)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire out)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire out, long resetState)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire out, long resetState, java.lang.String name)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire out, java.lang.String name)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, BV resetState)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, BV resetState, java.lang.String name)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, long resetState)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, long resetState, java.lang.String name)

downcnt(Node parent, Wire clk_en, Wire load, Wire load_data, Wire term_cnt, Wire out, java.lang.String name)

Method Summary

boolean	cellInterfaceDeterminesUniqueNetlistStructure() When false, the default behavior of this method, each cell will list itself separately in a netlist, guaranteeing that the netlist will not have invalid data at the expense of a larger file-size.
void	clock() Clock is used in the behavioral model and is called once per clock cycle
static byucc.jhdl.contrib.modgen.outputs	compute(int load, long load_data, long out, int width) Used in behavioral model to compute the output.
static byucc.jhdl.contrib.modgen.BVoutputs	computeBV(int load, BV load_data, BV out, int width) Used in behavioral model to compute the output.
void	connectImplicitPorts() Connects the implicit ports.
protected boolean	defaultSimulationModelIsBehavioral() Default simulation model is behavioral
java.lang.String	getCellName() Access the cell name associated with a derived class.
void	propagate() Propagate isn't used in this class
void	reset() Resets the output to the user-provided reset state.

Methods inherited from class byucc.jhdl.Logic.Logic

clockDriver, clockDriver, connect_implicit_ports, constructSubCell, constructSubCellNoImplicitPorts, enableNewPlacement, enableNewPlacement, extend, extend, getDefaultClock, getDefaultTechMapper, getGlobalClock, getSinkCell, getSourceCell, getSourceCell, getSourceLeaf, getSourcePlaceable, getSourcePlaceableLeaf, getSubCellClass, getTechMapHint, getTechMapHint, getTechMapper, growAndShiftl, lockChildPlacement, lsb, lsb, map, map, map, map, map, map, map, map, map, map, map, map, map, map, map, map, map, map, map, msb, msb, msbIndx, netlist, netlist, netlist, netlist, netlist, netlist, netlist, netlist, padClock_o, padClock_o, padClock_o, padClock, padClock, padClock, padIn_o, padIn_o, padIn_o, padIn, padIn, padIn, padInout_o, padInout_o, padInout_o, padInout, padInout, padInout, padOut_o, padOut_o, padOut_o, padOut, padOut, padOut, padOutT_o, padOutT_o, padOutT_o, padOutT, padOutT, padOutT, place, place, place, place, place, place, place, place, place, place, place, place, place, place, place, place, place, printTechMapHints, range, rotate, rotate, scale, scale, setBBox, setDefaultTechMapper, setFloorPlannerIsMaster, setTechMappingEnabled, setWandH, signExtend_o, signExtend, signExtend, sink, source, takeBot_o, takeBot, takeBot, takeBotSigned_o, takeBotSigned, takeTop_o, takeTop, takeTop, techmap, techMappingEnabled, translate, translate, zeroExtend_o, zeroExtend, zeroExtend, zeroExtendRight_o, zeroExtendRight

Methods inherited from class byucc.jhdl.Logic.LogicStatic

add_o, add_o, and_o, and_o, and, and, buf_o, buf_o, buf, buf, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, constant_o, constant_o, constant_o, constant_o, constant_o, constant_o, constant_o, constant_o, constant, constant, constant, constant, constant, constant, constant, constant, constant, constant, gnd_o, gnd_o, gnd, gnd, gnd, gnd, mux_o, mux, nc, nc, nc, nc, nc, nc, not_o, not_o, not, not, or_o, or_o, or, or, reg_o, reg, vcc_o, vcc_o, vcc, vcc, vcc, vcc, wire, wire, wire, wire, xnor_o, xnor_o, xnor, xor_o, xor

Methods inherited from class byucc.jhdl.Logic.LogicGates

add_o, add_o, add_o, add_o, add_o, add_o, add, add, add, add, addsub_o, addsub_o, addsub_o, addsub_o, addsub_o, addsub_o, addsub, addsub, addsub, addsub, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and_o, and, and, and, and, and, and, and, and, and, and, and, and, and, and, and, and, and, and, ashiftr_o, ashiftr, ashiftr, buf_o, buf_o, buf, buf, checkValueRepresentableInWidth, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat_o, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, concat, constant_o, constant_o, constant_o, constant_o, constant_o, constant_o, constant_o, constant_o, constant, constant, constant, constant, constant, constant, constant, constant, constant, constant, gnd_o, gnd_o, gnd, gnd, gnd, gnd, mux_o, mux_o, mux_o, mux_o, mux_o, mux_o, mux, mux, mux, mux, mux, mux, name, nand_o, nand_o, nand_o, nand_o, nand_o, nand_o, nand_o, nand_o, nand_o, nand_o, nand_o,