boog - Online in the Cloud

PROGRAM:

NAME

BooG - Binding and Optimizing On Gates.

SYNOPSIS

boog [-hmxold] input_file output_file [lax_file]

DESCRIPTION

boog is a mapper of a behavioural description onto a predefined standard cell library as
SXLIB. It is the second step of the logic synthesis: it builds a gate network using a
standard cell library.

Input file description
The logic level behavioural description (.vbe file) uses the same VHDL subset as the logic
simulator asimut, the FSM synthesizer syf, the functional abstractor yagle and the formal
prover proof (for further information about the subset of VHDL, see the "vbe" manual).
Some constraints due to hardware mapping exist. These attributes are only supported by
technology mapping onto a standard cell library as sxlib.
For the register signal description, only one condition statement must appear. STABLE must
be strictely used as a negativ motion and joined to clock setup value. Setup can be on
high or low value, but it would be worthy to choose it accordingly with hardware register
cell.
# Example
label: BLOCK (NOT ck 'STABLE and ck='1')
BEGIN
reg <= GUARDED expr;
END BLOCK;

You can also put a write enable condition to your register:
label: BLOCK (NOT ck 'STABLE and ck='1' and wen='1')
BEGIN
reg <= GUARDED expr;
END BLOCK;

A special feature has been introduced in the VHDL subset in order to allow the don't care
description for external outputs and internal registers : A bit signal can take the 'd'
value. This value is interpreted as a '0' by the logic simulator asimut. Don't Cares are
automatically generated by syf in the resulting '.vbe' file.

Output file description
A pure standard cell netlist is produced by boog. This file is destinated for /fBloon/fP
alliance utility to improve RC delays. Any equipotential keeps its name from connector to
connector. In trouble case, buffers are inserted to respect this VHDL constraint.

lax Parameter file description
The lax file is common with other logic synthesis tools and is used for driving the
synthesis process. See lax(5) manual for more detail.

lax uses a lot of parameters to guide every step of the synthesis process. Some
parameters are globally used (for example, optimization level whereas others are
specifically used (load capacitance for the netlist optimization only). Here is the
default lax file (see the user's manual for further information about the syntax of the
'.lax' file):

Optimization mode = 2 (50% area - 50% delay)
Input impedance = 0
Output capacitance = 0
Delayed input = none
Auxiliary signal saved = none

Mapping with a standard cell library
Every cell appearing in the directory defined by the environment variable MBK_TARGET_LIB
may be used by boog since they are described as a '.vbe' file. There are some restrictions
about the type of the cell used. Every cell has to have only one output. The cell must be
characterized. The timing and area informations required by boog are specified in the
"generic" clause of the ".vbe" file.

OPTION

-h Help mode. Displays possible uses of boog.

-m optim_mode
Optimization mode. Can be defined in lax file, it's only a shortcut to define it
on command line. This mode number has an array defined between 0 and 4. It
indicates the way of optimization the user wants. If 0 is chosen, the circuit
area will be improved. On the other hand, 4 will improve circuit delays. 2 is a
medium value for optimization.

-x xsch_mode
Generate a '.xsc' file. It is a color map for each signals contained in
output_file network. This file is used by xsch to view the netlist. By choosing
level 0 or 1 for xsch_mode, you can color respectively the critical path or all
signals with delay graduation.

-o output_file
Just another way to show explicitely the VST output file name.

-l lax_file
Just another way to show explicitely the LAX parameter file name.

-d debug_file
Generates a VBEdebug file. It comes from internal result algorithm. Users aren't
concerned.

ENVIRONMENT VARIABLES

The following environment variables have to be set before using boog :

MBK_CATA_LIB gives the auxiliary paths of the directories of input files (behavioural
description).

MBK_TARGET_LIB gives the path (single) of the directory of the selected standard cell
library.

MBK_OUT_LO gives the output format of the structural description.

EXAMPLE

You can call boog as follows :
boog alu alu

Use boog online using onworks.net services